A Guide to Locke's Essay

Author: Garth Kemerling

Table of Contents

Introduction 4

Aims and Methods 4

The Great Concernments 5

A Simple Preview 6

Other Philosophers 7

Simple Ideas 9

Origin in Experience 9

Ideas of Sensation 10

Primary and Secondary Qualities 12

Ideas of Reflection 13

Animal Thinking 15

Complex Ideas 17

Modes 17

Relations 18

Substances 19

Representational Reliability 21

Words 22

Language 23

General Terms 24

Real and Nominal Essence 25

Simple Ideas and Modes 27

Human Knowledge 28

No Knowledge is Innate 28

Achieving Certainty 29

Degrees and Types of Knowledge 31

The Limits of Knowledge 32

Severe Restrictions 32

Probable Knowledge 35

God 36

Thinking Substances 36

The Existence of God 36

Faith and Reason 37

Morality 38

Grounds for Moral Reasoning 40

Demonstrable Rules 41

Varieties of Moral Law 42

Human Action 43

Freedom and Responsibility 43

Hedonistic Motivations 46

Pursuit of Happiness 47

Moral Agents 48

Sortal Identity 48

Personal Identity 50

The Natural World 52

Bodies 53

Causality 54

Introduction

John Locke's An Essay Concerning Human Understanding is a classic statement of empiricist epistemology. Written in a straightforward, uncomplicated style, the Essay attempts nothing less than a fundamental account of human knowledge-its origin in our ideas and application to our lives, its methodical progress and inescapable limitations.

Even three centuries later, Locke's patient, insightful, and honest reflections on these issues continue to merit the careful study that this guide is intended to encourage.

Aims and Methods

Locke prefaced his masterwork with a rhetorically understated "Epistle to the Reader." His awareness of the need for a systematic investigation of the human understanding first arose in the context of a friendly but unproductive discussion of other issues. (According to another of the participants in that meeting, they included "the Principles of morality, and reveald Religion.") Although he drafted a preliminary account that dealt with many of the central themes of the Essay as early as 1671,

Locke expanded his comments repeatedly before publishing the book nearly twenty years later and continued to supplement them with additional material he prepared for four further editions. Claiming only to be an "Under-Labourer" whose task is to prepare the way for the "Master-Builders" of science, he encouraged ordinary readers to rely upon their own capacity for judgment rather than to accept the dictates of intellectual fashion. [Essay Epistle]

In the daily course of ordinary activity, everyone is inclined to rely upon a set of simple guidelines for living, and laziness or pride may encourage us to accept dearly held convictions without ever embarking on a careful examination of their truth. But this is a dangerous course.

Locke pointed out that blind acceptance of "borrowed Principles"-the confident pronouncements of putative cultural authorities regarding crucial elements of human life-often leaves us vulnerable to their imposition of absurd doctrines under the guise of an innate divine inscription. [Essay I iii 24-26] Our best defense against this fate is to engage in independent thinking, which properly begins with a careful examinination of the function and limits of our discursive capacities.

Attention to specific issues at hand often leads us to overlook the function of the most noble of our faculties, but Locke believed that the operations of the human understanding are familiar to us all. We employ ourselves in thinking, deciding, doing, and knowing all the time. What we require is not a detailed scientific explanation of the nature of the human mind, but rather a functional account of its operations in practice.

For that purpose, Locke supposed, we must pursue the "Historical, plain Method" of observing ourselves in the process of thinking and acting. With respect to each significant area of human knowledge, we must ask ourselves: where does it come from, how reliable is it, and how broadly does it extend? [Essay I i 1-2]

The last of these questions is arguably most to the point. Locke realized early on in his epistemological reflections that skeptical doubts often arise from unreasonable expectations about the degree of certainty it is possible for us to attain. [King, p. 107] Academic philosophers have contributed to the problem by demanding demonstrative certainty of the speculative truth even in instances where we are unlikely to be able to achieve it.

But their demands for excessive precision in philosophical language lead only to pointless wrangling over the meanings of their terms, on Locke's view. The simple truth is that we can't be certain about everything, and it would be counter-productive to try to expand our knowledge beyond its natural limits.

Since we are not capable of knowing everything, contentment with our condition requires a willingness not to reach beyond the limitations of our cognitive capacities. Our intellectual energy would be most efficiently employed were we to avoid intractable disputes over matters beyond our ken and rely instead upon our "Satisfaction in a quiet and secure Possession of Truths, that most concern'd us." [Essay I i 7] In ordinary life, we know what we need to know, and expecting more than that would only lead us to despair.

The Great Concernments

After all, Locke argued, we do have what we need most. The practical conduct of human life doesn't depend upon achieving speculative certainty about the inner workings of the natural world or acquiring detailed information about our own natures.

It will be enough if we can secure "the Conveniences of Life" and recognize what we ought to do. How short soever their Knowledge may come of an universal, or perfect Comprehension of whatsoever is, it yet secures their great Concernments, that they have Light enough to lead them to the Knowledge of their Maker, and the sight of their own Duties.

Men may find Matter sufficient to busy their Heads, and employ their Hands with Variety, Delight, and Satisfaction; if they will not boldly quarrel with their own Constitution, and throw away the Blessings their Hands are fill'd with, because they are not big enough to grasp every thing. [Essay I i 5] The pursuit of happiness-the genuine business of human life, on Locke's view-demands only that religion, morality, and science be established to a degree that permits practical progress.

Even with respect to such vital matters, Locke supposed, our knowledge is often limited. The testimony of our senses, together with a natural inclination to seek pleasure and avoid pain, guides much of our daily conduct even though sensitive knowledge cannot offer demonstrative certainty about the existence of an external world. [Essay IV xi 8-10]

It would be foolish indeed to refuse to eat simply because God has not granted us speculative certainty regarding the nutritional efficacy of food. Divine provision for the practical needs of human life is expressed more economically: So in the greatest part of our Concernment, he has afforded us only the twilight, as I may so say, of Probability, suitable, I presume, to that State of Mediocrity and Probationership,

he has been pleased to place us in here. [Essay IV xiv 2] The pace of ordinary life commonly requires all of us to act quickly, on the basis of little more than our fallible memory of the merely probable evidence in favor of this course of action, Locke supposed, but awareness of this common reliance on "our mutual Ignorance" appropriately motivates broad toleration of the diversity of opinions and practices to which others may adhere. [Essay IV xvi 3-4]

The great theme of the Essay, then, is that we ought not to expect to achieve knowledge beyond the relatively narrow confines of what is necessary or, at least, useful for the practical conduct of human life. Although speculative knowledge of the essences of God, human beings, and material things exceeds the capacity of our cognitive faculties, according to Locke, we have no grounds for complaint. Observation of the causal regularities in nature enables us to secure our survival and comfort, "ease, safety, and delight," during this life.

What is more, evaluation of our moral conduct in the light of our accountability to God for the actions we perform provides amply for our hope of a better existence beyond this life. Limited though it may be, Locke supposed, the human capacity for knowledge is sufficient for our happiness here and hereafter, and since that is that is our primary concern, it would be pointless to demand that our faculties reach any further. [King, pp. 86-92]

A Simple Preview

A year before the first edition was published, Locke wrote an "Abstract of the Essay." Translated into French by his friend Jean le Clerc, this document was published in the Bibliothèque Universelle in 1688, giving the European intellectual community a full preview of the work to come. This presentation of the central themes indicates what Locke himself regarded as his most significant contributions to the subject.

After a mere mention of the polemic against innate ideas, Locke explained his own belief that all human thought originates in the simple ideas of sensation and reflection. He devoted particular attention to the primary/secondary quality distinction and to the acquisition of simple ideas of space, time, number, pleasure, and pain. Then he outlined the account of our formation of crucial complex ideas, including those of substances, mixed modes, and relations. [King, pp. 365-378]

Noting his own belated discovery of the vital importance of language, Locke offered a basic statement of his own theory of language, with special attention to the relation between general terms and abstract ideas. Drawing the distinction between civil and philosophical uses of language, he pointed out that difficulties in communication result both from the natural imperfections of language and from its deliberate misuse. [King, pp. 378-388]

Finally, Locke defined knowledge and distinguished its several types, each of which is subject to strict limitations. Arguing in some detail against the common inclination to rely upon supposedly self-evident principles, Locke proposed that genuine advances in human knowledge depend instead upon the proper exercise of good judgment in assenting to opinions suitable to the ideas with which they are concerned. [King, pp. 388-398]

Other Philosophers

Locke rarely commented explicitly on the relation of his own work with that of other thinkers. Sharing the wide-spread seventeenth-century scorn for sectarian proponents of scholastic philosophy, he warned that reliance upon supposed authorities-ancient or modern-more commonly hinders than helps the pursuit of truth. [Conduct 24] Nevertheless, Locke wrote with an extensive and thorough knowledge of the philosophical tradition.

Though he decried the evils of the slavish "Aristoteleans," Locke himself often relied upon the writings of Aristotle, especially in matters of logic and ethics. The influence of classical Stoicism, especially as represented by Cicero, is also evident at many points in the Essay. Medieval philosophers and theologians seem to have made rather less of an impression on him, though it is likely he would have known the work of Augustine, Aquinas,

and Ockham. Locke expressed great respect for Francis Bacon, on whose discussions of language and logic he relied, but often criticized Thomas Hobbes, whose analyses of volition and political organization clearly influenced his own thinking.

Locke's relationship to the French Cartesians is more complex. Although he obviously respected the fresh initiatives René Descartes had brought to seventeenth-century philosophy, Locke had serious reservations about the success of the Cartesian approach. He explicitly criticized its identification of body with space under the attribute of extension and its emphasis on the ontological argument for God's existence.

Although he sometimes presupposed a dualistic account of human nature, Locke disputed many of its Cartesian corrolaries, including the continual thinking of the soul and the absence of thought in animals, and he notoriously suggested the possibility that matter might have the power to think. In general, Locke disavowed the over-reliance on mathematical reasoning at the expense of sensory observation in the pursuit of human knowledge. His letters include several critical examinations of Gassendi and Malebranche as well.

Among his contemporaries, Locke more clearly admired scientists than philosophers. Although he knew many of the Cambridge Platonists, Locke shared few of their convictions, and his attack on innatism may well have been addressed against them. From his friend Robert Boyle he gleaned the distinction between primary and secondary qualities, along with a profound appreciation for the corpuscularian theory of matter.

Of course he reserved high praise for the achievements of Isaac Newton, though Locke's grasp of Newtonian mathematics often seems rather shaky, and the letters the two exchanged were most frequently concerned with biblical interpretation. Locke's own training in the medical sciences did occasionally provide ready examples for points under discussion in the Essay.

Despite the modesty with which he offered his epistemological reflections, Locke showed great interest in the public reception they received. Publication of the "Abstract" drew ample attention even before the book itself had appeared, and from that time on, Locke's correspondence was full of suggestions and complaints from other thinkers.

Even when he later modified his views, however, Locke rarely acknowledged this reflected the influence of such criticism, which he tended to regard as unjustified attacks borne of malicious mis-reading. He persistently declined to engage in a direct correspondence with Leibniz; only the hapless Bishop Stillingfleet succeeded in drawing him into a public debate. On the whole, there is little evidence of the openness to critical reflection Locke frequently expressed in his letters to friends like Molyneux, le Clerc, Tyrrell, and Burnett.

Simple Ideas

Locke used the word "idea" for the most basic unit of human thought, subsuming under this term every kind of mental content from concrete sensory impressions to abstract intellectual concepts. Explicitly disavowing the technical terms employed by other philosophical traditions, he preferred simply to define the idea as "whatsover is the Object of the Understanding when a Man thinks." [Essay I i 8]

Locke worried little about the ontological status of ideas. He did commonly refer to them as being "in the Mind," both when we are conscious of them and when they are stored in memory, he regarded this as no more than a spatial metaphor. Locke was interested in these immediate objects of perception only because they point beyond themselves.

Thus, the crucial feature of ideas for Locke was not what they are but rather what they do, and the epistemic function of an idea is to represent something else. For since the Things, the Mind contemplates, are none of them, besides it self, present to the Understanding, 'tis necessary that something else, as a Sign or Representation of the thing it considers, should be present to it: And these are Ideas. [Essay IV xxi 4]

Because we do think and must always be thinking about something or other, then, it follows that we actually do possess ideas. [Essay II i 1] If we want to comprehend the foundations for human knowledge, Locke supposed, it is natural to begin by investigating the origins of its content.

Origin in Experience

Since knowledge-indeed, human thought of any sort-is mediated by ideas, it is well worth asking how we acquire them. Thus, in Book II of the Essay, Locke embarked on an extended effort to show where we get all of the ideas that we do so obviously possess. An adequate genetic account will explain, at least in principle, how human beings acquire the ability to think about anything and everything.

Let us then suppose the Mind to be, as we say, white Paper, void of all Characters, without any Ideas; How comes it to be furnished? Whence comes it by that vast store, which the busy and boundless Fancy of Man has painted on it, with an almost endless variety? Whence has it all the materials of Reason and Knowledge?

To this I answer, in one word, From Experience: In that, all our Knowledge is founded; and from that it ultimately derives it self. [Essay II i 2] The human mind is like a camera obscura for Locke, a darkened room into which bright pictures of what lies outside must be conveyed. [Essay II xi 17]

Locke had already argued at length that ideas are not innately imprinted on the human mind. Observing children reveals that their capacity to think develops only gradually, as its necessary components are acquired one by one. No individual idea is invariably present in every human being, as one would expect of an innate feature of human nature,

and even if there were such cases, they could result from a universally-shared experience. Everything that occurs to us either arrives directly through experience, or is remembered from some previous experience, or has been manufactured from the raw materials provided solely by experience. [Essay I iv]

From the outset of the project, then, Locke took the empiricist stance that the content of all human knowledge is ultimately derived from experience. We can only think about things we're acquainted with in one or the other of two distinct ways: Our Observation employ'd either about external, sensible Objects; or about the internal Operations of our Minds, perceived and reflected on by our selves,

is that, which supplies our Understandings with all the materials of thinking. These two are the Fountains of Knowledge, from whence all the Ideas we have, or can naturally have, do spring. [Essay II i 2]

Notice that Locke distinguished sensation and reflection by reference to their objects. We acquire ideas of sensation through the causal operation of external objects on our sensory organs, and ideas of reflection through the "internal Sense" that is awareness of our own intellectual operations. As the rest of Book II is designed to show, these two sources provide us with all of the ideas we can ever have. [Essay II i 3-5]

The acquisition of ideas is a gradual process, of course. Newborn infants, Locke supposed, are first aware of the vivid experiences of their own hunger or pain. Then, by further experience, they acquire a supply of sensory ideas from which they can abstract, learning to distinguish among familiar things.

Only later do they attend to their reflective experience of mental operations in order to acquire ideas of reflection. [Essay II i 21-24] Since we come to have ideas only by means of our own experience, Locke supposed, any interruption of this normal process could prevent us from having them.

Having defective organs of sense, artificially restricting experience, or inattentively observing what we have can all limit our possession of mental contents. [Essay II i 5-8] Individual human beings therefore exhibit great differences in their possession of simple ideas, and Locke speculated that other sentient beings-having, for all we know, experiences very different from our own-are likely to form ideas of which we can have no notion at all. Since simple ideas are acquired only by experience, anything we do not experience is literally inconceivable to us. [Essay II ii 1-3]

Ideas of Sensation

Everything begins, then, with simple ideas of sensation. Most of these are uniquely produced in the mind through the normal operation of just one of the organs of sense. Our ideas of colors, sounds, smells, tastes, and heat, Locke supposed, are acquired respectively through our eyes, ears, noses, tongues, and skin. Lacking the appropriate organ in any of these cases would wholly prevent our having any of the characteristic ideas of that sense. With normal sensory organs, we come to have so many simple ideas of sensation that we don't bother to invent words naming all of them. [Essay II iii 1-2]

Notice that these ideas tend to be either the unnamed determinate instances of some determinable predicate (particular shades of blue and varieties of sourness) or sensations easily identifiable by association with other ideas (the taste of pineapple and the fragrance of a rose). According to Locke, certain special simple ideas are acquired by two different senses.

Space, extension, figure, motion, and rest are all presented to us both in sight and in touch; they are therefore among the most commonly received of all our ideas of sensation. [Essay II v] Because of their prominence, specific ideas of these kinds constitute the basis for the most fundamental organization of our sensory experience. All of them represent primary qualities of sensible objects and serve significant roles in science and ordinary life. Things that can be both seen and touched seem most obviously real to us.

But is it correct to suppose that one and the same idea can be acquired from either of two distinct senses? Since simple ideas of sensation cannot be acquired through defective sensory organs, on Locke's view, it should be impossible to acquire the visual idea of motion from tactile sources alone. Locke's Irish friend William Molyneux posed this problem with precision in letters to the Bibliothèque Universelle and to Locke himself.

[Correspondence 1064, 1609, 1620.] Supposing that someone blind from birth became familiar with solid figures by touch alone and then later gained the power to see, would this person be able to distinguish a cube and a sphere by sight alone without first touching them? In a passage added to the Essay's second edition, Locke agreed with Molyneux (on a view confirmed by twentieth-century empirical research) that the answer must be no.

[Essay II ix 8] The visual and tactile ideas of the globe are distinct. Although we use the same words to designate ideas of shape and motion whether they have come from sight or from touch, only "an habitual custom" associates ideas from distinct senses with each other.

In a few, even more special instances, simple ideas are produced in us by reflection as well as sensation. These are ideas that are invariably present in the mind in association with every other object of thought, no matter what its source. According to Locke, such ideas of both sensation and reflection include pleasure, pain, power, existence, and unity. [Essay II vii] Among these existence and unity secure yet another aspect of the organization of our experiences, by providing clear conceptions of reality. Pleasure and pain, as we'll see later, play a special role in motivating us to exercise the volitional power behind all human actions, of mind and body.

Primary and Secondary Qualities

Although Locke assumed that simple ideas of sensation are invariably produced in our minds by the influence of external objects on our organs of sense, he did not suppose this causal process to be straightforwardly representational: there need not always be something in the object that corresponds directly with the idea it produces in us.

In some cases, for instance, it is the absence, rather than the presence, of some determinate feature in the thing that produces "a real positive Idea in the Understanding." [Essay II viii 1-2] Even on a causal theory of perception, privation is a change in the sensory organ, and therefore fully perceptible. Thus, our ideas of cold, darkness, and (perhaps) rest are produced by the absence of heat, light, and motion in things.

Despite the systematic ambiguity of our usual vocabulary, Locke maintained, we should always distinguish between ideas themselves, the immediate objects of thought as entertained by the mind, and qualities, the causal powers by means of which external objects produce those ideas in us. [Essay II viii 7-8] An examination of the causal processes involved in formation of our sensory ideas thusly led Locke to propose an important distinction among the qualities of bodies:

The primary qualities of any body are features Locke took to be inseparable from it, both in the sense that they are the kinds of features we experience to be aspects of every body and in the sense that we suppose that they would remain present even if the body were divided into imperceptible parts. [Essay II viii 9]

Our ideas of the primary qualities include those of solidity, extension, figure, motion, rest, and number. Notice that all of these ideas are perceived by touch and that all except solidity are perceivable by sight as well.

Since bodies operate only on mechanistic principles, our perception of such ideas can only result from a direct contact between our organs of sense and the object itself-or, in the case of vision at a distance, an imperceptible particle from the object itself. [Essay II viii 12] Such qualities therefore exist as features of the body itself, independently of their perception.

Secondary qualities, on the other hand, Locke held to be nothing in the object itself except a causal power to produce ideas of a certain sort-a color, a taste, or a sound, for example-in us. Like the mere powers of producing change in other objects, these supposed qualities are nothing other than effects produced by the genuine (primary) qualities of bodies themselves. [Essay II viii 10]

Notice that all of our ideas of secondary qualities are produced in us only by a single sense; their perception clearly depends upon the normal operation of our sensory apparatus in response to the merely dispositional properties of things. Thus, our customary supposition that such qualities really exist in nature is nothing more than a reification of the ideas that are actually produced in our minds by the primary qualities of things. [Essay II viii 14-17]

Locke's arguments in defence of this thesis may be familiar from their prior statement in Galileo, Descartes, and Boyle or from their later appropriation by Berkeley and Hume.

The color and taste of manna (a natural laxative) are less like its powdery texture than like its effect on the digestive tract; although things themselves remain the same in darkness as in light, their color appears only through the mediation of rays of light; contrapositively, the mechanical process of grinding an almond can change only its primary qualities,

yet the secondary qualities are thereby modified; and a single body of tepid water can seem both warm and cool at the same time, if our fingers have been differentially chilled and heated beforehand. [Essay II viii 18-21] In every case, the proper conclusion is that the ideas of secondary qualities are produced in us only by the mechanical operation of the primary qualities of bodies.

From this distinction, Locke concluded that there is a significant difference in the representational reliability of primary and secondary qualities. Our ideas of primary qualities resemble the qualties themselves; the mind-independent features of material objects are (at least at the microscopic level) exactly as we perceive them to be. But our ideas of secondary qualities and powers resemble nothing in the material world; they are the causal consequences, in our minds, of the mechanical action upon our sensory organs of corpuscular primary qualities. [Essay II viii 23-24]

As his Royal Society companion Robert Boyle had shown, the rapid motion of insensible particles of matter is a genuine feature of objects, a primary quality that can be transmitted mechanistically from one body to another: as a result, fire has the power to melt other bodies and-in the same way-to produce in us the ideas of warmth, heat, or even pain. [Essay II viii 15-16]

Ideas of Reflection

Although he insisted that human awareness begins with simple ideas of sensation, Locke did not believe that they comprise all of our mental contents. We also acquire simple ideas of reflection through an objective observation of our own mental operations. In any these operations, the human mind must be either passive or active, Locke supposed, and the most fundamental ideas of reflection are therefore just two in number:

perception, in which the mind passively receives ideas, and volition, in which it actively initiates something. [Essay II vi 1-2] Every other idea of reflection, on Locke's view, is a simple mode of one or the other of these two basic types. All human mental activities derive from the faculties of understanding and will.

We are naturally familiar with such activities, since they constitute the whole of our conscious thought, but this does not entail our having clear conceptions of them. Familiarity without careful attention provides only confused ideas of our own mental operations. As Locke had already noted, the components of experience we first acquire are vivid sensory impressions of the external world. It is only with increasing maturity and a capacity for detachment that we grow able to make the careful inward observations from which clear ideas of reflection may arise. [Essay II i 7-9]

Even when we have acquired clear ideas from reflection, Locke supposed, we often designate them with a vocabulary drawn from the concrete context of sensory experience, representing our "inner" mental operations by an implicit reference to observable "outer" processes. [Essay III i 5]

The first and simplest of our ideas of reflection is that of perception, the passive reception of ideas through the bodily impressions made by external objects upon the organs of sense. Although perception in this sense is distinguished from thinking generally by the relatively meager degree to which it falls under our voluntary control, Locke believed it always to require some degree of conscious attention.

Physical stimulation of the sensory organs does not produce ideas unless the mind is attentive. [Essay II ix 1-4] Here Locke tilts to a significant feature of our sensory experience. Although we are almost constantly bombarded by physical stimuli-any one of which will, in the ordinary course of things, produce in our minds a particular sensory idea-we never perceive all of them and sometimes exercise deliberate control over which ones we do perceive.

Attention, choice, and judgment can all influence the operation of the officially passive faculty of perception. [Essay II ix 7-8] Another of our cognitive capacities is the ability to retain ideas in the mind over time, either in continuous contemplation or in recollection of ideas after a period of inattention. Although he naturally relied upon the spatial metaphor of memory as a "Store-house" or "Repository" of ideas, Locke emphasized that the ideas we can recall are not actually in the mind-that is, we are not conscious of them at all-during the inattentive interval. Memory is just the power to bring to mind ideas that we are aware of having perceived before without simply perceiving them anew. [Essay II x 1-2]

Like Descartes, Locke assumed that the proper function of human memory relies upon some physical process within the human body, as shown by the gradual effacement of infrequently experienced ideas and the loss of memory as a result of bodily disease. [Essay II x 4-5] On the other hand, some ideas are more firmly and easily retained than are others.

Greater degrees of attention and frequent repetition of experience have some influence on this, but Locke supposed that the most important factor is the association of certain of our ideas with pleasure and pain. The retention of ideas thusly correlated with the achievement or loss of happiness is one of the benevolent provisions for the needs of human life, since it motivates us to avoid or prefer experiences of appropriate sorts. [Essay II x 3]

Being able to remember our past experiences of hunger or headache without actually feeling their pain, he argued, encourages us to act in such ways as are likely to forestall their recurrence. [Essay IV xi 5-6]

Our reflective ideas of other mental operations receive much shorter treatment. Discerning is the mental operation of distinguishing among our ideas--either quickly by wit or carefully in sober judgment. This is a vital tool in providing the supply of distinct ideas whose interrelations we intuitively grasp in assenting to self-evident truths. [Essay II xi 1-3]

In the same fashion, the activity of comparing gives rise to our knowledge of relations by noticing non-exact similarities among our ideas. [Essay II xi 4-5] Compounding is the mental capacity to manufacture new complex ideas out of relatively simple components, while abstracting is the ability to make general use of particular ideas in more general reference by stripping away their indexical features.

These processes are especially vital because they ground our linguistic competence in employing general terms and secure the possibility of universal knowledge. [Essay II xi 6-9] Distinguished by their phenomenal quality, other cognitive powers are comprehended by the reflective ideas of sensation, remembrance, recollection, contemplation, reverie, attention, study, dreaming, and ecstasy. [Essay II xix 1-2]

Animal Thinking

Although each human being must acquire the ideas of reflection by observation of her own mental operations, on Locke's view, the activities thusly conceived may then be attributed to other sentient beings, qualified with the suspicion that they may vary greatly in degree from case to case. [Essay III vi 11]

There is ample evidence of individual variations even among similarly-constituted fellow humans, and it is reasonable to suppose that non-human thinkers could differ in ways that we cannot literally imagine. Although our own faculty of perception is perfectly suited to the conduct of human life, for example, Locke noted explicitly that other spirits, whose embodiment involves sensory organs different from our own, might well perceive aspects of the world of which we are unaware. [Essay II xxiii 12-13]

Dependent as we are on a sense of sight with a particular acuity, we can only speculate how the natural world might appear to beings whose visual abilities were different, much less those for whom the senses of smell or hearing are more fundamental.

Although Descartes and his followers had dogmatically argued that non-human animals, lacking possession of a separable thinking substance or soul, must therefore be incapable of thinking in any form, Locke preferred to examine the empirical evidence in an effort to discover to what degree animals may be capable of engaging in mental activity of each sort. [Essay II i 19] The intellecual capacity for perception, Locke held, marks the distinction between animal and plant life, and the sensory faculties of each species are well-suited to the practical needs of life for animals of that sort.

Since individual human beings differ widely in their intellectual abilities, Locke even speculated that those of some animals may exceed those of the least gifted of human thinkers. [Essay II ix 11-15] In the case of the retention of ideas, he suggested that the behavior of songbirds clearly exhibits their deliberate effort to learn a new tune. [Essay II x 10]

Nevertheless, Locke believed that the higher intellectual abilities of animals are strictly limited. They do not compare or discern ideas that lie beyond their immediate "sensible Circumstances," nor are they capable of compounding the new complex ideas required for engaging in mathematical thought. [Essay II xi 5-7] Most notably, he maintained that non-human animals are utterly incapable of abstraction.

Even if their sensory capacities permit them to engage in some degrees of intuitive thinking, then, their inability to form abstract ideas and employ general terms make it impossible for them to rise above particularity in order to engage in moral reasoning.

[Essay II xi 10-11] Thus, Locke preserved a significant moral distinction between human beings and other animals without grounding it on an ontological distinction in the possession of an immaterial soul. ©1999-2002 Garth Kemerling.Last modified 27 October 2001.Questions, comments, and suggestions may be sent to: the Contact Page.

Complex Ideas

Although he granted that some groups of simple ideas naturally occur together in our experience, Locke supposed that most of our complex ideas are manufactured in the human mind by the application of its higher powers. Combining joins several simple ideas together in the formation of a new whole; comparing brings two distinct ideas together without uniting them, giving rise to the idea of a relation between them; and abstracting separates some aspect of an idea from its specific circumstances in order to form a new general idea.

Repeated applications of these powers, Locke supposed, give rise to the whole variety of ideas human beings are capable of having. [Essay II xii 1-2] If we're going to analyze the epistemic origins our complex ideas, it will be helpful to consider the ways in which we gradually build up our supply of them.

On Locke's view, complex ideas are of three varieties: Modes are invariably conceived as the features of something else, which are never capable of existing independently. Substances, on the other hand, are understood to be the existing things in which modes inhere. Relations are nothing more than mental comparisons in some respect among other ideas. [Essay II xii 3-7] Complex ideas of all three sorts are manufactured by the mind from simpler components.

Modes

A simple mode is a complex idea all of whose component parts are variations or combinations of a single simple idea. [Essay II xii 4-5] Consider, for example, the simple idea of space: acquired initially from our senses of sight and touch, this idea provides the sole content for a host of related ideas of our own manufacture.

The notion of one-dimensional length can be "folded" upon itself to yield those of area in two dimensions and capacity in three; these notions, in turn, can be modified more subtly to provide our ideas of shapes and figures. Even the notion of place in relation to other bodies within a framework Locke believed to be abstracted from the simple idea of space. [Essay II xiii 2-6]

In similar fashion, Locke supposed that the simple idea of unity, repeatedly recombined with itself, provides the entire content for the simple modes of number, including even that of infinity. [Essay II xvi - xvii] In every such case, the complexity of the simple mode arises only from an iteration of a single simple idea, upon whose content the complex idea therefore relies.

Mixed modes, on the other hand, are complex ideas whose components include several distinct simple ideas, often including those derived from different experiential sources. Although such ideas can be acquired through observation of their instances in our experience, Locke supposed that they are much more commonly manufactured by the mind as complex ideas before we first apply them to the world. [Essay II xxii 1-2] This is an important feature of our complex ideas of mixed modes. Among them are included the conceptions we form of human activities, which typically involve not only ideas of sensation describing the overt action but also ideas of reflection regarding the intention with which it is undertaken.

For Action being the great business of Mankind, and the whole matter about which all Laws are conversant, it is no wonder, that the several Modes of Thinking and Motion, should be taken notice of, the Ideas of them observed, and laid up in the memory, and have Names assigned to them; without which, Laws could be but ill made, or Vice and Disorder repressed.

Nor could any Communication be well had amongst Men, without such complex Ideas, with Names to them: and therefore Men have setled Names, and supposed setled Ideas in their Minds, of modes of Actions distinguished by their Causes, Means, Objects, Ends, Instruments, Time, Place, and other circumstances; and also of their Powers fitted for those Actions. [Essay II xxii 10]

The idea of stabbing, for example, typically involves a deliberate act of penetrating flesh without any presumption about the instrument employed to do so. In such cases, it may be worthwhile for legislative bodies to conceive of such actions and condemn them as criminal without having to have experiential evidence of their first occurrence. [Essay III v 2-6] The only thing that matters for the formation of a mixed mode, on Locke's view, is the convenience of its use for us.

This clearly varies among distinct cultures, since the frequency with which we have occasion to notice, denominate, and evaluate actions of particular sorts often depends upon their social context. Invented wholly for our own use in matters of moral and legal import, the ideas of mixed modes have only that specific content we choose to give them. [Essay II xxii 5-12] As we'll see next time, the freedom with which such ideas are manufactured renders problematic our ability to use a common vocabulary in reference to them.

Relations

Complex ideas of relations derive from the mental operation of comparing distinct ideas without thereby combining them together into an entirely new whole. [Essay II xii 1, 7] Since this comparison considers each of the ideas in light of its extrinsic conformity with the other, it is commonly expressed by means of one of a pair of reciprocal relative terms-"parent"/"child" or "cause"/"effect," for example.

This is not invariably the case, however, so we must be alert to the possibility that apparently positive terms implicitly signify comparison with something else: "old" or "imperfect," for example. The tip-off to such cases, on Locke's view, is that (as in the case of relations of the other sort) removal of the correlative destroys the relation completely, rendering the term inapplicable. [Essay II xxv]

Many of our ideas of relations are acquired through sensory experience of the modes of time, place, and number. The correlative ideas of cause and effect are a special instance, on Locke's view: observing the changes produced in one thing by the operation of another, we form a sensitive notion of the causal relation even though we have no conception of the underlying mechanism at all. [Essay II xxvi 1-6]

Because language is devised for our convenience in satisfying the needs of ordinary life, things that are commonly connected in observation give rise to our complex ideas of natural relations. But we also conceive of instituted or voluntary relations between things that are corrleated with each other only by virtue of our own personal or social agreements.

Among these, on Locke's view, the most important and vital are the moral relations drawn between the complex ideas of specific human actions, together with their circumstances and goals, and the moral rules by reference to which we evaluate them. [Essay II xxviii 1-4] We'll look at these much more closely later on.

Substances

According to Locke, the complex idea of a substance is a collection of simple ideas that is believed capable of existing independently. Observing in experience that several features recur together frequently, we suppose that there must be some common subject that has all of them. Thus, for Locke, the "Notion of pure Substance in general" is nothing but the assumption of an unknown support for a group of qualities that produce simple ideas in us; our only notion of this putative "substratum" in itself is the confused notion of "that which" has these features, or "something, I know not what." [Essay II xxiii 1-3]

Locke consistently ridiculed the use of such scholastic terms as "Inhaerentia" and "Substantia" as pointlessly circular efforts to provide a positive idea of something for which, in fact, "we have no Idea of what it is, but only a confused obscure one of what it does." From this, he supposed, we can infer little of the metaphysical nature of reality. [Essay II xxiii 17-20]

Nevertheless, just as we combine simple ideas of qualities and powers to form the complex ideas of individual substances, we also gather many distinct things under the even more complex ideas of collective substances-army, world, and universe. [Essay II xxiv 1-3]

To the confused idea of substance in general, Locke held, we add either the ideas of regularly observed sets of sensory qualities, in order to form the notion of a bodily substance, or the reflective ideas of various kinds of mental operation, in order to form the notion of a spirit or thinking thing. Since the underlying nature of the substrate is equally obscure in both cases, the "secret and abstract Nature of Substance in general" is equally unknown to us for substances of either sort. [Essay II xxiii 4-6]

We do have clear and distinct ideas of the primary qualities of both bodies (solidity and impulse) and mind (thinking and motivity) even though our sensation and reflection offer no insight into "the internal Constitution, and true Nature of things," so that the relation and/or independence of bodies and minds remains an open question. [Essay II xxiii 29-32]

Thus Locke argued that even though we are often more familiar with material objects than with spirits, our ideas of them may be no clearer, and the customary prejudice in favor of bodily substance is philosophically indefensible. [Essay II xxiii 15-16]

With respect to bodily substances, the most accurate complex idea we could form, on Locke's view, would be one that includes the ideas of those active powers and passive capacities that it exhibits in its interaction with other things-the magnetism of the lodestone and the flammability of wood-along with its characteristic weight, color, or heat.

Since he believed the primary qualities of bodies to reside in the unobservable texture of their sub-microscopic parts, Locke found it natural to suppose that we classify distinct kinds of body by reference to the secondary and tertiary qualities these unknown features produce in us or other things. [Essay II xxiii 7-10] To express one of Locke's favorite examples in our own idiom, we were able to identify genuine pieces of gold for centuries before we had any clue to its atomic structure.

Representational Reliability

Several late chapters of Book II are devoted to a detailed discussion of the success with which ideas of various kinds perform their representative functions. The point here is that since we use ideas as signs, it is vital to be aware of the likelihood that they do actually point beyond themselves to their intended referential objects. The extent to which they serve these functions will determine the reliability of any knowledge we try to acquire about those objects.

Locke explained the clarity of ideas by analogy to visual perception: just as an object is seen clearly when viewed in suitable light, a clear idea is one of which we have a "full and evident perception," whose content is present before the mind. An idea is distinct, on the other hand, when it is perceived to differ from all others. [Essay II xxix 2-5]

Locke had no stake in differentiating sharply between the clarity and distinctness of ideas. In the Essay's fourth edition, he made a half-hearted effort to substitute the single adjective "determined" in place of the customary pair "clear and distinct." His central concern was with the failure of this representational function, in ideas that are confused. This occurs most frequently with respect to complex ideas, whose simple components may be too few or too poorly organized to determine their content precisely.

The problem, Locke argued, is that we often use words as if we knew their significance when, in fact, the ideas associated with them are not fully conceived. [Essay II xxix 7-11] We'll consider this issue more fully next time, but it's worth noting that Locke believed that many apparently intractable philosophical disputes arise from a failure to employ words to signify clear and distinct ideas.

His examples here all arise from the wide-spread failure to hold in mind a correctly-formed, determined idea in association with the word, "infinity." [Essay II xxix 13-16]

In Locke's taxonomy, and idea is said to be real (as opposed to fantastical) so long as there is something that it represents. Notice that the accuracy of representation is not at issue here at all. Even if the idea fails to correspond to its object, it is real provided only that the object does exist. Since simple ideas are passively received in the mind, for example, they must be caused by something real, even though-as we've already seen-in the case of secondary qualities they fail to resemble their causes. [Essay II xxx 1-2]

Because our complex ideas of modes and relations are not supposed to refer to anything else beyond their own archetypal content, they are all real as well. Ideas of substances, however, are intended to refer to existing things and are therefore fantastical if things with the appropriate combinations of features do not in fact exist. [Essay II xxx 4-5]

An idea is further said to be adequate only if it represents its intended object fully and perfectly; inadequate ideas convey the nature of their objects only partially. [Essay II xxxi 1] Locke insisted that all simple ideas are adequate, though doing so required some fancy footwork with respect to our ideas of secondary qualities. Properly understood, he argued, simple ideas represent whatever power it is that produces them in us, whether or not the idea resembles that power-which, in the case of secondary qualities, it does not.

As with the reality of ideas, so with their adequacy the vital point for Locke was the causal process by means of which we acquire them; our lack of voluntary control over that process forestalls any possibility of mistake or erroneous judgment. [Essay II xxxi 2, 12] Because complex ideas of modes and relations are assembled by the mind without reference to any external archetype, they are their own archetypes, which they cannot fail to capture adequately.

Although our communication with each other about such ideas (especially in the case of mixed modes) may falter because we do not agree about the signification of words we both employ, the ideas themselves are invariably adequate. [Essay II xxxi 3-5, 14] Once again, it is complex ideas of substances that are unreliable; such ideas, according to Locke, have a double intended reference but are inadequate in both respects.

If they are supposed to represent the substantial forms of existing things, our ideas of substances are inadequate because (on the corpuscularian theory) these real essences are unknowable. Even when considered more modestly, as collections of properties that co-exist in a common substrate, our complex ideas of substances are merely partial approximations, since it is clear that they include only those features we have most commonly observed; it always remains possible for us to be surprised by the discovery of another property that belongs just as surely in the same being.

[Essay II xxxi 6-11] As always, ideas derived from experience can be no more adequate than the experience itself, and with respect to natural things our experience is limited.

Although he maintained that truth and falsity are most properly regarded as characteristic of propositions, Locke granted that ideas are sometimes said to be true or false (better: right or wrong) by virtue of the role they play in the formation or assertion of such propositions. [Essay II xxxii 1-5]

It is the relation between ideas and the words used to signify them that matters for this representational criterion. Because of their familiarity in our experience and the frequency of our discourse about them, our ideas of natural substances and their qualities are often truly signified by the common terms we employ to designate them. [Essay II xxxii 6-10]

It is the ideas of mixed modes, manufactured independently in the minds of individual thinkers and lacking any external referent, that are most commonly false in this linguistic sense, because we do not agree on the signification of their names. [Essay II xxxii 11-13]

On the whole, then, Locke believed that ideas provide a vital but imperfect foundation for human discourse and knowledge. As we continue our study with an examination of his philosophy of language and of knowledge, we'll be reminded of the limitations imposed by the reliability of ideas of each type.

Words

Since the significatory function of words is especially vital for the achievement and expression of human knowledge, Locke devoted an entire Book of the Essay to his careful examination of "the Nature, Use, and Signification of Language." [Essay II xxxiii 19] On Locke's view, language is the instrument of all human social interaction, for the employment of which we are provided with three crucial requirements: First, we have appropriate physical organs with which to form a great variety of articulate sounds.

Second, we have the capacity for using these sounds as "Signs of internal Conceptions," with which we communicate our thoughts to each other. Third, in order to avoid the inconvenience of trying to have unique names for everything, we have the ability to employ words as general terms applied commonly to many particular things. [Essay III i 1-3]

Lesser creatures lack the third requisite and superior beings somehow communicate (in ways we cannot imagine) without the first, Locke supposed, but human beings rely upon spoken language as a primary vehicle for communication. Like thought itself, language is designed to serve the practical needs of human life.

Language

The question, then, is how we achieve our communicative goals, and Locke proposed a deceptively simple theory: words signify ideas. Since my own ideas are inaccessible to others, I employ the articulate sounds of human speech as extrinsic sensible objects by means of which to convey my thoughts to others. The absence of any universal human language, Locke argued, shows that the connection between each word and the idea it signifies is not natural but purely conventional, an association established by "voluntary Imposition." [Essay III ii 1-2]

Frequent repetition renders this association so intimate that some ideas may be induced more easily by words than by their referential objects, yet the freedom with which individuals form the requisite association often makes it difficult for a speaker to be sure that the appropriate idea has actually been induced in a hearer. [Essay III ii 6-8]

Both the equivocal use of terms and the invention of needless jargon by the learned, Locke supposed, amount to violations of the conventional agreements upon which language is properly founded. [Essay III x 5, 11]

There is a fundamental problem here: since ideas differ from person to person, and even in a single individual at different times, and since the association of word to idea is purely voluntary, even when secured by conventional agreement, it follows that the correct signification of a particular use of any word depends wholly upon the particular idea in the mind of its speaker, to which the hearer has no access except through the mediation of the word. [Essay III ii 2-4] On this view of language,

it is always possible that two people interact with each other verbally even though they do not achieve genuine communication because they do not associate similar ideas with the words they employ. In principle, I can never be sure that the sensory idea you experience in association with the word "red" is at all like the one I have when I use that word.

Locke officially granted only two kinds of exception to the general principle that every meaningful word signifies some idea. The first kind of exceptional case includes negative terms-"nothing" or "ignorant," for example. We don't need a distinct idea in mind for each of these words, Locke held, since we already have the positive idea whose absence each negative term signifies. [Essay III i 4] The other, more significant, exception comprises syncategorematic terms, what Locke called "particles"-such words as "is," "of," and "but."

Such words are not associated with particular ideas, Locke supposed, but "are all marks of some Action, or Intimation of the Mind." Thus, on theoretical grounds, these terms are techinically insignificant, but serve the important role of providing helpful guidance for interpreting the mental dispositions upon which human reasoning so often depends. [Essay III vii]

General Terms

The use of general terms is one of the most vital features of linguistic competence. Even though existing things-including words themselves- are invariably particular, Locke held that three considerations demand that some words be employed in a general signification: having a distinct word for each and every particular thing would exceed our linguistic and intellectual capacities;

unique names for particular ideas would make it impossible to communicate with others who do not share exactly the same ideas; and the most significant varieties of knowledge are precisely those that comprehend many particulars under some general rule. Thus, we have a natural prejudice in favor of general terms. Only under special circumstances will the practical needs of life override it in favor of having distinct names for particular things. [Essay III iii 1-5]

Since the signification of any word is an idea, Locke supposed that the signification of every general term must be an abstract idea, employed by the mind in reference to many particular things. General and Universal, belong not to the real existence of Things; but are the Inventions and Creatures of the Understanding; made by it for its own use, and concern only Signs, whether Words, or Ideas. Words are general, as has been said, when used,

for Signs of general Ideas; and so are applicable indifferently to many particular Things. [Essay III iii 11] Thus, on Locke's view, the classification of particular things into sorts or kinds, denominated by general terms, has no direct foundation in nature; it is, instead, the end result of our own complex process of abstraction. [Essay III iii 12-14]

Essences are nothing more than abstract ideas formed by the mind to provide significance for general terms, and their presumed immutability derives from our own power to retain the precise content of an abstract idea even in the absence of conforming instances. [Essay III iii 19-20] Formed by the mind, abstract ideas may differ from person to person, resulting in disputes over the applicability of the general terms that signify them. For "ordinary Conversation," however Locke held that minor variations of this kind may be tolerable, even for instances when one person's conception happens to be far more comprehensive and accurate than the other's. [Essay III vi 20, 31]

Even though our urge to classify things into sorts arises from the observation of genuine similarities among them, then, it is satisfied only by the provision for practical communication with general terms that designate abstract ideas. Every distinct abstract idea creates a distinct species of things by governing the applicability of a distinct general term. [Essay III vi 38]

As Locke pointed out, this makes it easier for us to classify artifacts than to discover the presumed genera of natural things. Having devised the artificial things themselves, we already have a conception of their structure and operations, and this provides a rich basis for the abstract ideas by means of which we sort them. [Essay III vi 40-43] It's easier to be clear about what "clocks" are than it is to decide whether or not "cardinals" belong to the "finch" family.

In general, Locke denied that human classificatory activity is ever governed by reference to natural kinds. The species of mixed modes by means of which we differentiate among human actions, for example, are devised entirely for our convenience in communication; the abstract ideas that represent such actions are held together precisely by their association with the general terms that signify them in ordinary speech. [Essay III v 9-11]

Even in the case of substances (to which we will return shortly) Locke argued that a mistaken belief that our classification must be drawn by reference to natural kinds or substantial forms amounts to an abuse of language, since it is founded upon a pair of false suppositions: that there are such natural kinds and that we have knowledge of them. [Essay III x 20-21] The false expectation that classification is natural can only lead to profound skepticism about the possiblity of general knowledge.

Real and Nominal Essence

Locke drew a careful distinction between two senses of the word "essence." Understood etymologically, as the very being of a thing, the real essence can only be that particular internal constitution from which all of the perceived qualities of a thing causally flow. Understood scholastically, as the ground for human classification of things into species and genera, on the other hand, the nominal essence is nothing more than the abstract idea, conformity with which justifies application of the associated general term. [Essay III iii 15]

For both simple ideas and modes, he supposed, these two "essences" invariably coincide, but for substances they are always different. Sortal terms for kinds of substances signify abstract ideas whose content rarely even appears to coincide with an internal stucture or compositions from which their features might be presumed to flow.

The nominal essence signified by the general term "human being," for example, would just be the idea by comparison with which we recognize individual instantiations of our own species, not the unknown (and perhaps unknowable) genetic structure that generates the development of a human life. [Essay III vi 1-3]

Locke held out for the possibility that there is some real essence (perhaps a set of primary qualities) that do in fact generate all of the observable features (many of them secondary qualities and powers) that make individual things what they are. But since our knowledge includes neither a direct awareness of that inner essence nor an understanding of the causal processes by which it produces ideas of its features in us,

it would be pointless and counter-productive to suppose that such knowledge is required for the practical task of classifying them. [Essay III x 17-18] When we try to use general terms to speak about the true nature of either material or thinking substances in themselves, then, we are pursuing a fool's errand and must of necessity fail to accomplish what we set out to do.

The practical use of general terms to sort out varieties of familiar substances is a different process altogether. Here, Locke supposed, a speaker observes the natural regularity with which certain features are observed to occur together, combines and abstracts the ideas of these features to form the abstract idea of a kind of substance, associates a general term with this abstract idea, and then applies the term to new instances of the same experience, without claiming thereby to fathom the true nature or real essence of such things. [Essay III vi 46-48]

In order to serve our practical communicative needs, Locke supposed, the process must employ nominal rather than real essences.

We find it convenient to associate a single general term to each abstract idea, rather than repeatedly generating a tedious list of specific features. But it follows that the distinction of species is entirely a product of the human understanding rather than a fixed aspect of nature itself. [Essay III vi 34-35]

On the one hand, this makes the (nominal) essence genuinely ingenerable and incorruptible: each general term designates an abstract idea whose pristine purity is unaffected by the existence or non-existence of any things that conform to it. [Essay III vi 19-20] On the other hand, it also makes the distinction of species perfectly arbitrary, framed for the convenience of human discourse rather than out of any respect for the real essences of natural things. [Essay III vi 38-41]

For each sort of substances, we choose a few "leading Qualities" as characteristic marks of such things, to which we commonly add a few other features-including especially the active and passive powers- that we have found often to coexist with these marks, forming the nominal essence by virtue of which we determine the applicability of a general term. [Essay III xi 19-21] When it comes to the classification of substances into sorts, it's all about us.

Simple Ideas and Modes

Although simple ideas carry with them a presupposition of real existence, Locke held, the names of simple ideas signify both the real and the nominal essences of the qualities they represent. [Essay III iv 2-3] Like the simple ideas themselves, which are involuntarily received in perception, the names of simple ideas have non-arbitrary content.

We find it difficult (and, usually, unnecessary) to classify them into sorts, and when we do so-as, for example, with colors or sounds-it is typically by reference to their perceptual origins rather than any supposed ideational similarity. [Essay III iv 16-17] Similarly, because each simple idea is a uniform perception, easily retained and intended to conform only to itself as an archetype, our names for simple ideas are rarely vulnerable to imperfection; the more simple the idea, the less likely we are to misuse the word that expresses it. [Essay III ix 18-19]

One consequence of all this is that the names of simple ideas are indefinable. At peril of an infinite regress, the provision of verbal definitions must ground out on some indefinable terms, and since simple ideas have no component parts that could be assembled under the direction of an appropriate definition, their names are perfectly suited to that role.

Scholastic efforts to offer definition of such simple ideas as motion or light, Locke argued, are ludicrous precisely because they so patently fail to produce any new idea in the minds of those who hear them. Imagine the comparable folly of trying to provide auditory definitions of visual ideas, or vice versa. [Essay III iv 4-11]

The names of mixed modes, on the other hand, are general terms that signify abstract ideas governing species of human actions. These names clearly are definable, since it is always possible in principle to offer a comprehensive list of those simple ideas which, assembled together by the mind, would constitute the appropriate complex idea.

That's why we don't need to witness an act of sacrilege or experience the resurrection of the dead in order to understand what kind of events those terms would signify. [Essay III v 1-5] Thus, Locke supposed that the initial formation of the abstract idea (and the stipulation of the name associated with this mixed mode) can be freely performed without any possibility of error.

It is only the subsequent use of the same word by other members of the same language-community that become vulnerable to mistake because they may fail to associate the word with the already-intended idea. [Essay III vi 43-45]

Here, even more obviously than in the case of substances, our acts of naming and classification are purely arbitrary, lacking any natural foundation. We do not discover the categories of human action (or their moral significance) as existing patterns of the natural world, but rather invent them in accordance with our own decisions about how to pursue practical life amongst one another. [Essay III v 6-9]

The vocabularies of morality, religion, and law are entirely of our own devising. This renders the use of such terms less problematic, Locke noted, and makes their misuse and confusion even less excusable.

Human Knowledge

Having explained the origin of our ideas and the use of words to signify them, Locke was prepared to consider the nature of human knowledge. He began with a simple definition: Knowledge then seems to me to be nothing but the perception of the connexion and agreement, or disagreement and repugnancy of any of our Ideas. In this alone it consists. [Essay IV i 2]

This definition gives rise to an obvious objection: if all human knowledge were wholly concerned with ideas, then it would lack an adequate foundation in reality and there would be no difference between the wise contemplation of philosophers and the fanciful but coherent imagination of the insane. Locke's response was two-fold: with respect to general knowledge, he boldly defended its detachment from anything other than our ideas, but with respect to knowledge of particulars he tried to show that there is a legitimate cognitive state that "goes a little farther than bare Imagination." [Essay IV iv 1-2]

Actual knowledge occurs only when we are actually perceiving the agreement in question, Locke supposed; our inclination to assent to what we've known in the past but are not presently attending to he called habitual knowledge. This capacity is clearly important for the development of learning generally; we can't focus on everything at once,

and it makes sense to rely upon our memories for general truths we have mastered on some occasion in the past. [Essay IV i 8-9] Thus, it makes sense to say that I know (habitually) the multiplication tables even at moments when I'm thinking about other things, provided that I can, upon challenge, call to mind the product of 8 and 7. The more crucial issue about human knowledge is to explain how it occurs in the first place.

No Knowledge is Innate

One account Locke unambiguously rejected from the outset is the supposition that human knowledge is innately inscribed. Noting the remarkably wide-spread agreement of individual human beings in their acceptance of both speculative and practical principles, the innatist argues that universal consent implies an innate origin.

Locke's response was two-fold: He denied the supposed fact of universal consent, supposing this to demonstrate the falsity of the innatist view. What is more, Locke argued that if there were any genuine instances of universal consent, they would more naturally be explained by universal possession of an intellectual faculty or by acquisition through some universal experience. [Essay I ii 1-2]

Granting that if general truths about logic were innately know by all human beings, then they must also be universally accepted, Locke emphatically denied the consequent. If the innatists were correct, then children (and mental defectives) would be the most pure and reliable guides to logical truth; but they are not. [Essay I ii 24-27] Of course the innatist reply to such counter-examples is to suppose that assent to innately inscribed principles is delayed until each individual is able to employ the faculty of reasoning.

But why should this be? Either reason is necessary for the discovery of such principles, in which case they are not innately known, Locke argued, or else reason and logic are merely coincidental features of human development, in which case both seem frivolous. [Essay I ii 6-13] Surely, in fact, the use of reason is properly concerned with our assent to general truths.

Locke agreed with the innatists that there is a significant distinction between truths to which we assent immediately upon first framing them on the one hand and, on the other hand, truths that require our careful consideration. But this distinction between self-evident and acquired knowledge, he supposed, doesn't correspond to the innatist identification of the most fundamental truths.

We assent to specific instances at an earlier stage of development than to speculative maxims themselves, and this is most easily explained by the fact that we acquire the particular ideas involved in the former long before we have manufactured the abstract ideas required for the latter. [Essay I ii 14-19] Careful attention to the development of knowledge in individual cases clearly shows it to involve the gradual acquisition of the requisite ideas, perception of whose agreement or disagreement constitutes knowing in each instance.

Achieving Certainty

Locke's definition of knowledge as perception of the agreement (or disagreement) of ideas clearly indicates two fundamental criteria for acquiring knowledge: first, we have to have the requisite ideas, then we also have to perceive the connection between them. Failure on either of these counts will leave us short of the certainty characteristic of genuine knowlege. [Essay IV iii 1-2]

The extended genetic account of our ideas in Book II of the Essay was designed to assist in satisfaction of the first criterion, by helping us to acquire a suitable stock of clear and distinct ideas about many things. But even where our ideas are amply clear, we may fail to achieve certain knowledge if we are unable to recognize the ways in which they are related to each other. [Essay IV ii 15]

Consider, for example, how the two criteria apply to specific areas of possible human awareness: Our passive reception of simple ideas from external objects provides only practical assurance of the existence of the objects themselves, so our knowledge of material qualities and substances is always limited in certainty.

But non-substantial complex ideas refer to nothing outside themselves, so any connections we perceive among them are "infallibly certain." For this reason, as we'll see later, Locke held that all mathematical and moral reasoning is characterized by perfect certainty. [Essay IV iv 4-8]

What Locke's definition clearly demands is that all knowledge is relational in structure, or propositional in form; it invariably involves "the joining or separating of Signs, as the Things signified by them, do agree or disagree with one another." [Essay IV v 2] But since both ideas and words are properly understood as signs, Locke believed it vital in principle, though often difficult in practice, to distinguish between truth in thought and truth in language.

Ultimately he distinguished between mental propositions in which ideas are perceived to agree and verbal propositions that affirm the agreement of words. In both cases, the criterion of truth is that the relation of the signs conforms to a more fundamental agreement that holds among the things they signify. [Essay IV v 3-5] Naturally the two kinds of proposition are connected with each other.

Certainty about the truth of a verbal proposition requires that it accurately express the agreement of the ideas signified by its terms; certainty about the knowledge itself further requires that we actually perceive that agreement among ideas. [Essay IV vi 3]

Degrees and Types of Knowledge

Locke distinguished four types of agreement or disagreement that may be perceived in human knowledge: Knowledge of identity and diversity rests solely upon our recognition of the distinctness of each idea from every other; knowledge of relation employs positive, non-identical connections among ideas; knowledge of co-existence perceives the coincident appearance of a collection of qualities; and knowledge of real existence presumes some connection between an idea and the real thing it represents. [Essay IV i 1] He further supposed that these types of knowledge can occur in any of three degrees:

Intuitive knowledge is the irresistable and indubitable perception of the agreement of any two ideas without the mediation of any other. This is the clearest and most perfectly certain of all degrees of human knowledge. It accounts for our assent to self-evident truths and serves as the foundation up-on which all other genuine knowledge must be established. [Essay IV ii 1] Intuition is most common in our knowledge of identity and relation among clear ideas, but (following Descartes) Locke also supposed that each thinking being has an intuitive knowledge of its own existence. [Essay IV ix 3]

Even when the agreement of ideas is not intuitively obvious, it may be possible to discover a series of intermediate ideas by means reason establishes a connection between them. The resulting demonstrative knowledge of the agreement of the original ideas shares in the certainty of the intuitive steps by means of which it has been proven, yet there is some loss of assurance resulting from the length of the chain itself. [Essay IV ii 2-7]

The success of the entire process depends upon our having clear ideas at each step of the process of demonstration and upon our ability to perceive the agreements between them, and both of these conditions are specific to the nature of human intellectual abilities. [Essay IV iii 4, 26-28]

The most common area of demonstrative human knowledge is mathematics, where our possession of distinct ideas of particular quantities yields the requisite clarity, disciplined reasoning helps to uncover the intermediate links that establish knowledge of identity and relation, and a perspicuous system of symbolic representation helps us to preserve the results we have obtained. [Essay IV ii 9-10]

But Locke supposed that we may be capable of demonstrative knowledge of moral relations as well, provided that we take care in the formation of abstract ideas of the mixed modes of human action. Our only demonstrative knowledge of real existence, he supposed, is that we can have with respect to God. [Essay IV x]

Although only intuition and demonstration offer certain knowledge of general truths, Locke supposed that sensitive knowledge provides some evidence of the existence of particular objects outside ourselves. Although it is not always true that there must exist an external object corresponding to each of our ideas of sensation, Locke argued that veracious cases are different enough from illusory cases to warrant an inference to the real existence of their objects, especially when the accompanying perception of pleasure or pain serves as a reliable guide to the practical conduct of human life. [Essay IV ii 14]

Locke had serious reservations about the reliability of our sensitive knowledge of the natural world, and we'll return later to the chapter of the Essay he devoted entirely to an analysis of its difficulties. [Essay IV xi] ©1999-2002 Garth Kemerling.Last modified 27 October 2001.Questions, comments, and suggestions may be sent to:

the Contact Page.

The Limits of Knowledge

One of the most basic themes of Locke's epistemology is that since we cannot know everything, we would be well-advised to observe and respect the extent and limitations of human knowledge. Given the basic definition of knowledge as perception of the agreement of our ideas, it follows that we fall short of knowing whenever we lack ideas or fail to perceive their agreement.

Thus, intuition extendes only to the identiy and diversity of ideas we already have; demonstration extends only to ideas between which we are able to discover intermediaries; and sensitive knowledge informs us only of the present existence of causes for our sensory ideas. [Essay IV iii 3-5] Awareness of our limitations, Locke proposed, should forestall haste, laziness, and despair in our natural search for the truth about the most vital issues into which human knowers can fruitfully inquire. [Conduct 39-43]

Severe Restrictions

Applying the human faculty of reason to the pursuit of knowledge, properly defined, reveals the limitiations within which we must work: We cannot achieve knowledge of things-such as infinity or substantial real essences-for which we lack clear, positive ideas. Indeed, having ideas will not be enough to secure knowledge if-as in the case of human actions-they are obscure, confused, or imperfect. Given faulty memories, we may also fail to achieve knowledge because we are incapable of tracing long chains of reasoning through which two ideas might be demonstrably linked.

In a more practical vein, rational knowledge cannot be established upon false principles-such as those borrowed from conventional wisdom. Finally-in the effort to achieve philosophical or scientific certainty-our efforts to employ reason are commonly undermined by the misuse or abuse of language. [Essay IV xvii 9-13]

Most particularly, on Locke's view, it is difficult to secure the reality of human knowledge in any evidence of its conformity with the nature of things themselves. We readily assume that passively-received simple ideas must be providentially connected with their objects, and since complex abstract ideas are of our own manufacture,

it is our own responsibility to ensure their reality by a consistent use of the names by which we signify their archetypes. But complex ideas of natural substances are intended to represent the way existing things are independently of our perception of them, and of this the content of our ideas never provides adequate evidence. [Essay IV iv] These difficulties trouble all four types of knowledge.

Since knowledge of identity and diversity involves only a recognition that particular ideas are distinct, it is immediately evident whenever we have clear and distinct ideas; such knowledge must be among the earliest that any of us ever achieve. [Essay IV vii 9-11] Even otherwise ignorant beings might well be capable of perceiving the disagreement of ideas at this level, Locke pointed out, so knowledge of "identical Propositions" of this sort is generally uninformative (or "trifling")

rather than any genuinely instructive contribution to morality or science. [Essay IV viii 2-3] The general principle of identity merits no special status among our cognitive states, Locke held, since its particular instances are all either equally obvious or (because of the obscurity of our ideas) irredemable without it. [Essay IV xvii 14-19]

Knowledge of relation requires only that we are aware of non-identical connections among ideas, so (as we'll see in greater detail later) Locke supposed it possible wherever we have clear ideas, especially among the simple modes of number in mathematics and the mixed modes of human action in morality. [Essay IV vii 6] But since general knowledge of relations can never be derived from experimental observation-upon which we depend entirely for our knowledge of material things-it follows that we can never have certain knowledge of relations among substances. [Essay IV vi 10, 16]

What careful observation does provide is knowledge of the co-existence of a collection of qualities in a common subject. But because we are ignorant of the real essences from which observable qualities presumably flow, our knowledge of co-existence is never demonstrable, except in the trifling cases where we have already included the ideas of the qualities in our nominal essence for substances of this sort.

On Locke's view, then, natural science founded firmly upon solid understanding of the inner constitution and operation of material things remains impossible. [Essay IV vi 6-10] Even knowledge of real existence requires some awareness of the connection between the thing and the idea that represents it, and Locke supposed that we lack this in every case except that of self and God. [Essay IV vii 7] The extent of our perfect knowledge of the world and its operations is meager indeed.

Assent and Judgment But perhaps we don't need perfect knowledge very often. Although Locke emphasized the strict limits within which we can attain certain knowledge, he also believed that we invariably possess the cognitive capacities that will provide for the conduct of our everyday lives.

The Understanding Faculties being given to Man, not barely for Speculation, but also for the Conduct of his Life, Man would be at a great loss, if he had nothing to direct him, but what has the Certainty of true Knowledge. For that being very short and scanty, as we have seen, he would be often utterly in the dark, and in most of the Actions of his Life, perfectly at a stand, had he nothing to guide him in the absence of clear and certain Knowledge. [Essay IV xiv 1] Although we'd soon starve if we waited for demonstrative certainty about the nutritional value of food,

none of us forget to eat, since human life in what Locke called the "twilight … of Probability" is providentially supplied with alternative methods and motives for practical action. Rational proof is impossible for experimental natural science and uncommon in other matters regarding which we are too lazy to work through the demonstrations on our own,

Locke supposed, but in these cases we don't really have to have genuine knowledge. It is often enough to exercise the faculty of judgment, which accepts a presumptive agreement between ideas without demanding the certainty of a clear perception. [Essay IV xiv 3-4]

Functioning properly, this faculty persuades us to assent to propositions about whose truth we remain ultimately uncertain, whether our ignorance is the product of incomplete thinking or the secret nature of the thing itself. [Essay IV xvii 22] Although mathematicians can demonstrate that the interior angles of every plane triangle sum up to 180 degrees, for example, most of us rely upon their professional testimony rather than following the train of reasoning for ourselves.

Similar degrees of reliance upon less-than-demonstrative certainty Locke believed to support most of the propositions to which we commonly grant our assent. [Essay IV xv 1-2] When we lack demonstrative certainty, the role of judgment is to guide our actions in all of those cases regarding which the best we can do (or the best we are willing to do) is to observe that a pair of ideas often do seem to be related to each other in some way. [Essay IV xvii 16]

The probable knowledge gained by judgment differs from the demonstrative knowledge derived by reason in the nature of its evidence: while demonstration achieves perfect certainty by grounding itself on the clear, immutable connection of two ideas, probable knowledge merely guides our judgment with some degree of likelihood or the appearance of some connection.

Thus, while demonstration yields true knowledge, judgment can provide only some degree of confidence in our opinion, assent, or belief. [Essay IV xv 1-3] The great sources of evidence for our confident assurance of the likelihood of propositions to which we assent by judgment are our own experience and the testimony of others about what they have experienced.

Noting that we commonly evaluate the reliability of testimony by reference to our own experiences anyway, Locke proposed that we can and should depend more often upon things we have personally observed with some regularity than upon what could turn out to be nothing more than the prejudices or false opinions of other people. [Essay IV xv 4-6]

Probable Knowledge

Although the degree to which we assent to a probable proposition ought to depend upon the strength of the evidence in its favor, Locke granted that we often regulate our judgment merely be reference to our faulty memories of past experience.

It is both natural and (in a practical snese) necessary to rely upon the retention of past experience rather that developing our beliefs anew in every moment, it is a dangerous practice, because the propositions we acquire through exercise of the faculty of judgment are bound to remain genuinely uncertain.

Since the supposed relation between the ideas is founded only upon our present estimation of the available evidence, it is always possible in principle that the discovery of additional information in the future may lead us to overthrow or abandon a past judgment, as can never happen with truly demonstrative knowledge.

The difficulty of applying judgment successfully, Locke suggested, should encourage us to be patient and tolerant of those who disagree with us on matters about which neither side can claim anything more sure than probable opinion. [Essay IV xvi 1-4]

The highest possible degree of probable knowledge will occur in cases where the general consent of all human beings happens to coincide with my own invariable experience of some particular matter of fact. This, Locke supposed, will produce a level of assurance virtually indistinguishible from that of demonstrative certainty, and this explains our willingness to act without hesitation upon our conviction that such beliefs truly capture the nature of reality, even though we remain ignorant of the inner constitution of things themselves.

In cases that exhibit a less striking regularity in my own experience and that of others, the degree of my confidence in the probable proposition will be suitable reduced, Locke held, and even in the absence of any direct observation regularity, I am likely to accept the unanimous testimony of impartial witnesses with respect to any specific matter of fact. [Essay IV xvi 6-8]

When experience and testimony do not so clearly agree, Locke supposed, other methods may serve to guide the dictates of judgment. In legal and quasi-legal contexts, we develop a great deal of skill in evaluating the relative merits of conflicting testimony from distinct sources. In the natural sciences, we commonly employ analogical models in an effort to comprehend the real essences of which we are constitutionally ignorant. [Essay IV xvi 10-12]

In addition to all of these legitimate grounds for guidance, the faculty of judgment commonly falls victim to unworthy and unsupported claims to its assent. Someone may demand that I assent to the truth of a proposition only because it is defended by some putative authority, in the absence of any proof of its falsity, or solely because it agrees with other opinions I already hold.

But since all of these matters are formally irrelevant to the truth of the proposition in question, Locke supposed, they should have no bearing on my assent. The only legitimate grounds for agreeing with someone are demonstrative knowledge and probable judgment, both of which ultimately rest only upon "the nature of Things themselves." [Essay IV xvii 19-22]

God

Like many of his English contemporaries, Locke was deeply interested in matters of faith and religion. Keenly aware of the theological controversies of the day, he developed and defended views of his own that proved influential on the Deists of the next generation. Although knowledge of God is vital for human life and practical conduct, on Locke's view, it cannot be grounded legitimately on the supposedly universal possession of an innate idea. [Essay I iv 8-9]

Although he claimed to demonstrate the existence of God as the only reasonable explanation for the emergence of thought in an otherwise material world, Locke warned against an excessive reliance upon non-rational considerations in the defense of particular religious doctrines.

Thinking Substances

We form our complex ideas of spirits, Locke held, by adding the notions of a variety of cognitive powers (themselves acquired, as ideas of reflection, from careful observation of our own mental operations) to the abstract idea of substance in general. Since this is perfectly analogous to the way we form complex ideas of bodies from our ideas of sensation, the results are perfectly comparable: although we are familiar with both bodies and spirits in our ordinary experience, the real essences of thinking and moving substances alike remain forever unknowable. [Essay II xxiii 22-25]

It is easy enough to employ an empiricist version of Descarte's cogito ergo sum as a demonstration of my own existence, of course. Thinking of any sort, feeling pleasure and pain, even the act of doubting itself, are all experiences that carry with them a full assurance of my own existence as a thinking thing. [Essay IV ix 3] Notice, however, that Locke declined the further implications of the Cartesian inference to sum res cogitans.

Thinking, he argued, is merely an activity of the soul, not its essence; so the continued existence of an individual thinking thing does not necessarily entail its continuous consciousness. [Essay II i 10-16] Locke frequently expressed significant reservations about the demonstrability-if not the very truth-of Cartesian dualism.

Given our widespread ignorance of the inner constitution and operation of substances generally, Locke notoriously suggested that, for all we know, the power of thinking could be providentially superadded to an organic human body as easily as separate thinking and material substances could be combined. [Essay IV iii 6] But the ultimate origin of thinking itself is another matter.

The Existence of God

According to Locke, the existence of God is an instance of demonstrable knowledge in any reasoning being. Since I know intuitively that I exist as a thinking thing, and since nothing can be made to exist except by something else which both exists and has powers at least equal to those of each of its creations, it follows that from all eternity there must have existed an all-powerful cogitative being. [Essay IV x 3-6]

This amounts to a variation on the Aristotelean / Thomistic cosmological argument for God's existence: there is an instance of thinking; every thinking thing proceeds from some other thinking thing; but there cannot be an infinite regress; so there must have been a first thinking thing, or God.

What most interested Locke in this argument was its emphasis on thinking. Willing though he was to contemplate the possibility that individual human beings are animal bodies that have the power to think, Locke insisted that mere matter-with its primary qualities of solidity, mass, and motion-could never on its own give rise to cogitative activity of any kind. Although it may not strictly be inert, matter is most definitely unthinking. [Essay IV x 9-10]

Materialism can never account for the emergence of thought in a universe containing only senseless matter. Thus, from the fact that there is now thinking in the universe, it follows that there always has been thinking in the universe; the first eternal being from which all else flows must itself be a thinking thing.

What is more, Locke argued, it is likely (though not, technically, demonstrably certain) that this first eternal being is actually immaterial. Whether the original being were a single atom, or an eternal system of many parts, or whether every material thing thinks, Locke thought the possibility of a material thinking being at the start difficult to defend.

On his view, we don't even have respectable grounds for supposing that a separate material reality is co-eternal with the necessarily cogitative first being. [Essay IV x 13-18] Locke's insistence on this point fits nicely with his frequent assertions that atheism amounts to nothing more than the supposition that matter is itself eternal, an objection to the views defended by Hobbes.

So God exists, but what is God? Here, as always, Locke depended upon the formation of ideas on empirical foundations. Although we have no direct experience of God, we do have ideas of reflection from experience of our own mental activity, and we have an idea of infinity as a simple mode derived from the idea of number, indefinitely expanded: put these together,

and each of us develops an abstract complex idea of God as a being that possesses all cognitive abilities to an infinite degree. [Essay II xxiii 33-35] In principle, this idea differs from any of our other ideas of thinking things only in the infinity of the divine attributes. God is abolutely perfect in every conceivable respect, and this is ample provision for a deduction of the moral law.

Faith and Reason

Locke was also interested in traditional issues about the relation between faith (assent to revealed truth) and reason (discovery of demonstrative truth) as alternative sources of human conviction. For propositions about which the certainty of demonstrative knowledge is unavailable, our assent may be grounded upon faith in revelation; but Locke argued that the degree of our confidence in the truth of such a proposition can never exceed our assurance that the revelation is of genuinely divine origin, and this itself is subject to careful rational evaluation. [Essay IV xvi 14]

Since God has provided both avenues of belief for the benefit of human achievement, Locke supposed, they can never conflict with each other if properly used. Faith is appropriate, but only with respect to vital issues that lie beyond the reach of reason; to allow any further extent to non-rational religious convictions would leave us at the mercy of foolish and harmful speculations.

In any case where revelation (understood as an extraordinary communication from God) and ordinary human reason coincide in support of the same truth, Locke argued, it is reason that provides the superior ground, since our assurance of the reliability of the revelation itself can never exceed the perfection of demonstrative certainty. [Essay IV xviii 4-11]

Divorcing the (properly complementary) resources of revelation and reason, Locke supposed, is dangerous because it tends to encourage the promulgation of reckless claims of the revealed origin of otherwise incredible propositions. "Enthusiasm," as Locke and many of his contemporaries feared, rests solely upon the emotional strength of persuasion as grounds for assent, and this is formally independent of the objective likelihood of its purportedly divine origin. [Essay IV xix 4-9]

In a sense, then, reason emerges from Locke's discussion as the ultimate arbiter of all legitimate human assent: either it discovers the demonstrative connections through which the truth of an individual proposition can be established with certainty, or it plays the most crucial role in certifying the legitimacy of a revealed proposition as divine rather than merely delusive. [Essay IV xix 12-16] Even though faith can play a role in human life, reason remains the most important basis for genuine human knowledge.

Morality

From the early essays on the obligatory force of natural law to the careful revisions of later editions of the Essay, Locke continually displayed an intense interest in problems of moral philosophy. The proper aim of human knowledge, he supposed, lies not in the satisfaction of attaining abstract speculative truth, but rather in its application to practical conduct, upon which our happiness in this world and the next ultimately depends.

[King, p. 86-88] Ethical knowledge is a variety of what he called Praktikh, The Skill of Right applying our own Powers and Actions, for the Attainment of Things good and useful. The most considerable under this Head, is Ethicks, which is the seeking out those Rules, and Measures of humane Actions, which lead to Happiness, and the Means to practise them.

The end of this is not bare Speculation, and the Knowledge of Truth; but Right, and a Conduct suitable to it. [Essay IV xxi 3] Since our cognitive faculties are best suited for pursuing that knowledge of ourselves and God that is most likely to lead us toward the dutiful conduct by means of which we may secure eternal happiness, Locke argued, morality is the most vital aspect of study for all human agents. [Essay II xii 11] In what ways do human faculties establish the foundations of moral knowledge?

Grounds for Moral Reasoning

Given their great importance for human life, practical principles would be among the best candidates for special status as innately provided by a benevolent creator; but, of course, Locke held that there is no innate human knowledge. Lists of purportedly innate practical principles-like the ones noted by Lord Herbert-are in fact neither universally accepted nor reliably productive of correct conduct.

The open, remorseless disavowal of moral principles in various cultures, along with the open question for their justification, is ample evidence that they are not truly innate. [Essay I iii 11-19] Only the desires to achieve happiness and to avoid misery are both genuinely universal among human agents and practically effective in guiding their conduct, Locke argued, so it is only the natural tendency to seek pleasure and avoid pain that might reasonably be held to be innate.

To the extent that appropriate patterns of human conduct are found to be in widespread conformity with morality, he supposed, it is only in virtue of a providential association of moral rectitude with more short-sighted perception of personal and public welfare. [Essay I iii 3-6] Apart from these general inclinations, he believed, nothing about human morality is universally acknowledged.

Nevertheless, Locke was no moral relativist. Human moral discourse is subject to the kind of perfect precision that should yield the possibility of demonstrable truth. In principle, moral terms-which describe the varieties of human action and delimit the degrees of their rectitude in relation to moral law-are all perfectly definable, since each signifies a mixed mode whose determinate content is secured by its manufacture in the mind. [Essay III xi 15-17]

Although intellectual laziness, malicious arrogance, and culpable self-interest often render moral discourse problematic, Locke believed that careful, dispassionate attention to the complex ideas involved should produce demonstrable moral reasoning.

The mixed modes of human action are complex ideas derived from recombination of the simple ideas of thinking, moving, and power, so all the vocabulary of "Divinity, Ethicks, Law, and Politics" can be derived ultimately from our simple ideas of sensation and reflection. [Essay II xxii 10, 12] But notice that these ideas, and the words that signify them, can be fully formed in the mind independently of their actual instantiation.

We can know what sacrilege and resurrection would be without experiencing their occurrence; we choose to define single words for "murder" and "stabbing" but not for other ideas equally familiar in experience; but we form abstract ideas of those human actions to which we most commonly refer, whether or not they frequently occur. [Essay III v 5-7]

Thus, on Locke's view, such moral ideas as those of obligation, drunkenness, or lying, are formed by combining simple ideas from the mental and physical aspects of human nature without ever supposing that anything conforming to the new composite has ever existed. [Essay II xxii 1] This detachment from questions of real existence, Locke believed, is crucial for establishing the demonstrable status of human morality.

Demonstrable Rules

The moral rectitude of actions of a particular sort, Locke held, is wholly constituted by the demonstrable relation between our clear ideas of such actions and the equally clear conception of the moral law. Indeed, this relation is often so obvious-as, for example, in the cases of "murder" and "theft"-that the moral condemnation comes easily to be included as a part of our complex idea of the action itself. [Essay II xxviii 14-16]

Because both my contemplated action and the moral rule can be abstractly conceived as mixed modes, the applicability of this rule to that action can be determined with perfect certainty. It is a further question whether or not the moral rule itself is demonstrably true.

Locke believed that it often is. To be sure, reliance upon an axiomatic deduction of morality from a fixed set of putatively indubitable first principles would be neither effective nor intellectually sound. [Essay IV xii 4-5] Nevertheless, demonstration is possible in principle wherever we have clear ideas, and Locke was careful to emphasize that indubitable knowledge of relations does not presuppose perfect clarity with respect to the relata.

We might know that one automobile is faster than another, for example, even if we had little information about the mechanical differences that produce this result. Our awareness of relations commonly rises to a level of certainty greater than our knowledge of the things among which they hold. [Essay II xxv 4-8]

What counts toward demonstrability, on Locke's view, is the possibility of perceiving intermediate links between our ideas. Since the mixed modes of human action and the concepts of moral rules are both abstract ideas that serve as their own archetypes, it follows that the relations between them are fully demonstrable. [Essay IV iv 7-9] In this respect, at least, morality is on an equal footing with mathematics.

Where there is no Property, there is no Injustice, is a Proposition as certain as any Demonstration in Euclid: For the Idea of Property, being a right to any thing; and the Idea to which the name Injusticeis given, being the Invasion or Violation of that right; it is evident, that these Ideas being thus established, and these Names annexed to them, I can as certainly know this Proposition to be true, as that a Triangle has three Angles equal to two right ones.

Again, No Government allows absolute Liberty: The Idea of Government being the establishment of Society upon certain Rules or Laws, which require Conformity to them; and the Idea of absolute Liberty being for any one to do whatever he pleases; I am as capable of being certain of the Truth of this Proposition, as of any in Mathematicks. [Essay IV iii 18]

The apparent advantage of mathematical over moral reasoning, Locke speculated, rests only on the relative ease with which we can represent mathematical relationships in perspicuous diagrams and the relative absence of partisan concerns. Were we to approach moral reasoning with the same degree of objectivity we commonly bring to mathematical thinking, he argued, we would achieve the same quality of demonstrable certainty about substantive moral truths. [Essay IV iii 19-20]

Varieties of Moral Law

In general, Locke held that the mental comparisons comprising our ideas of relations are significant for the practical conduct of life. Natural relations among human beings, like the various degrees of blood-kinship, for example, commonly carry the presumption of some special obligation toward other members of our families. Instituted relations based on social agreement ground the governance of human societies, as we'll see in detail in a few weeks.

But moral relations are most vital of all, so that the very descriptions of human action under our ideas of mixed modes commonly carry with them an implicit reference to the moral law under which they are commanded or proscribed. [Essay II xxviii 2-4] Moral valuation, on Locke's view, derives from the demonstrable connections that hold among the ideas of duty,

law, legislator, and sanction. [Essay I iii 12-13] Since no moral law could determine human volition and thereby influence human actions practically without careful provision for punishment and reward as artificial consequences of disobedience and obedience, it follows that moral legislation must derive from legislation by intelligent beings with the power to enforce their dictates by appropriate moral sanctions. On this basis, Locke distinguished three basic types of moral law by reference to the legislative source of each: divine law, civil law, and the law of opinion or reputation. [Essay II xxviii 6-7]

The divine law arises from God's right as creator to dictate morality to all creatures of his own making, his wisdom and benevolence guiding them toward what is best, and his power to enforce this law by distributing in the hereafter punishments and rewards that are both infinite in extent and eternal in duration. Thus, Locke held that the resulting distinction between duty and sin is "the only true Touchstone of moral Rectitude," founded upon the ultimate happiness or misery attached by God to actions of particular sorts. [Essay II xxviii 8]

Thus, Locke held that denial of God's existence, moral legislation, or control over eternal life can only be attributed to an irrational hope of escaping moral law and the divinely ordained consequences of sin, since no one who professes such outrageous opinions is observed to live a life in accord with the Golden Rule. [King, p. 90]

In the second edition of the Essay, Locke carefully noted that the divine law may be known either through revelation or by the manifest light of natural law. In either case, he supposed, the divine law guides human conduct so obviously toward genuine happiness and away from profound misery that even public opinion and private interest commonly defer to its force: even those who behave badly themselves often praise or blame others by reference to the genuine criterion. [Essay II xxviii 8, 11]

The civil law derives its force from the legislation of a government to which its citizens have already consented. Since the commonwealth has been formed for the purpose of protecting "the Lives, Liberties, and Possessions" of its citizens, it has the power to take away any or all of these goods in punishment for the crimes of disobeying its rules of conduct. [Essay II xxviii 9] Although its penalties are more limited than the infinite sanctions of divine law, Locke supposed, their certainty and immediacy provide a secure basis for enforcement of the civil law.

Finally, the distinction between virtue and vice belongs only to the law of opinion or reputation and is sanctioned only by the praise or blame of others. Although public opinion always praises the virtuous, Locke noted, the standards of virtue and vice vary widely among different cultures, though some degree of conformity to the rational dicates of natural law is always to be expected. Although this level of moral law derives from a source no more significant than what other people happen to think, the threat of "Condemnation or Disgrace" from one's fellows is a powerful motivation for many human agents; few of us willingly invoke the disapprobation of others. [Essay II xxviii 10-12]

The emphasis on punishment and reward in these accounts of moral law draws attention to an important distinction between the grounds of moral obligation and the motivation for obeying it, both of which derive from the legislator. We are morally bound to obey because the creator has a right to command, but we are practically moved to obey because God has the power to punish us if we don't.

The practical force of morality-its capacity to determine volition and influence action-derives from the punishments and rewards that secure our compliance. Thus, Locke argued, good and evil are nothing other than pleasure and pain; moral good and evil are just the pleasure and pain artificially annexed to obedience and disobediance by the decree of the powerful legislator. [Essay II xxviii 5-6]

Moral motivation requires only that a rational agent consider the possibility of future pleasure or pain that will result from present actions, and Locke believed that the prospect of eternal happiness or misery ought therefore to weigh upon us at least as firmly as more short-term expectations. [Essay II xxi 70]

Human Action

The first edition of the Essay included a brief chapter, "Of Power," dealing with the nature of human volition. Despite the admiration of his friends, Locke expressed both surprise at the direction his thoughts had taken and confusion about the apparent incompatibility of divine omnipotence with human freedom. [Corr. 1592] Revisions made for the second edition made II xxi the longest chapter in the Essay.

Locke boasted about his willingness, as a sincere "Lover of Truth," to change his views publicly, yet confessed his remaining puzzlement about the more perplexing aspects of our abilities to think and to move, to produce changes in other things either by performing direct action or by forbearing so to do. [Essay II xxi 71-72] Since human action is "the great business of Mankind" on Locke's view, and since moral responsibility is commonly taken to presuppose some degree of freedom, it is vital for his task to seek some clarity on the nature of human action.

Freedom and Responsibility

Development of a basic vocabulary for the issue seems clear enough at first. The quasi-relational simple idea of power is present as an element of our observation of any case of change, both as the active force that produces the alteration and as the passive capacity of that which is changed. Since bodies most clearly exhibit the passive power to receive and communicate motion by impulse, our idea of the active power to initiate action derives primarily from reflection upon our own mental operations as we think or move ourselves. [Essay II xxi 1-5]

This, Locke held, is the power of volition, or the human will.

The liberty of a moral agent is just its further power either to perform or to forbear any action of thinking or moving according to its own mental preference. Clearly thought, volition, and will are all necessary conditions for having this kind of liberty, but on Locke's view they are not even jointly sufficient, since genuine liberty always presupposes the additional possibility of doing otherwise.

Even on those occasions when I do exactly what I want to do, I am not acting freely if there is something that would make me do this whether or not I willed it. It makes no difference whether the determinative force comes from outside me or from the internal operations of my own body, according to Locke, nor whether in compels me to perform an action that might be contrary to my volition or restrains me from performing an action that might be in conformity with my volition. Freedom is the power to do otherwise if my volition were to change. [Essay II xxi 7-13]

Although he never addressed the issue directly in the Essay itself, Locke confessed to Molyneux in correspondence that he found it difficult to reconcile the moral freedom of human agents with the presumed omnipotence and omniscience of God. [Corr. 1592]

Notice that on this account of liberty, the cause or explanation of the volition itself is irrelevant, since it is the agent (not the will) that is free. Human beings act freely just insofar as they are capable of translating their mental preferences to do or not to do into their actual performance or forbearance of the action in question. The ability to do as one wills is all that any moral agent could reasonably expect. [Essay II xxi 19-21]

Clarity of language, Locke proposed, would forestall the vaunted philosophical dispute about "free will." Since the will is just a power to contemplate possible actions in light of our mental preferences regarding them while liberty is the further power to perform actions in accordance with these preferences, it would be a category mistake to attribute one power to the other.

It is only the agent that has the power to will and the power to act, so it is only the agent that is free, not the will. [Essay II xxi 14-16] A demand for freedom of the will is therefore not only absurd but ultimately fatalistic. In particular situations, we must either perform an action or not, and our freedom in doing so is secured in the power to do as we will.

If this prior volition were itself another free "action," then it would have to be preceded by yet another, and so on: freedom would be acting in accordance with a volition that was itself freely performed in accordance with a wish that was freely undertaken, etc., etc ad infinitum. The vicious infinite regress would render freedom impossible. [Essay II xxi 22-25]

What is more, free will would be irrelevant to moral responsibility. Since human liberty is the capacity to act as one wills, agents act freely even when their wills have been determined, so they remain morally responsible and may be justly punished for those actions. [Essay II xxi 56]

In a lengthy correspondence with his Dutch friend Philippus van Limborch, Locke repeatedly insisted that emphasis upon the supposed "indifferency" of the will is theologically unsound and morally mistaken. [Corr. 2925, 2979, 3043, 3192] Only the insignificant actions of the insane are truly indifferent, on Locke's view, and the determination of volition is a necessary condition for undertaking any meaningful human action.

The more surely volition is determined toward pursuit of the good, the happier the agent will be. (God, for example, is supposed to be perfectly determined to the good, yet is surely also supposed to be free.) In the same way, a proper understanding of the causes of human volition will enhance, not undermine, confidence in our moral accountability. [Essay II xxi 48-50]

Hedonistic Motivations

In Locke's second-edition treatment of the issue, these causes are clear: human volition is a mental preference that is invariably determined by the greatest present uneasiness attendant upon desire. The presence of pain and the absence of pleasure now, along with the anticipation of either in the future, induce in us a feeling of uneasiness that can be satisfied only by removing the pain or achieving the pleasure.

Although we commonly experience many such desires at the same time, each proportional to the degree of pleasure or pain and the likelihood of its production, one among them always overcomes all of the others, and this most pressing uneasiness is the one that determines the will to act in such a way as to resolve it. [Essay II xxi 29-32]

If human agents were ever perfectly content in every respect, Locke supposed, they would have no volition and take no action; lacking nothing, they would experience none of the uneasiness that expresses itself in a desire that determines the will to produce a change of circumstances.

Thus, the recurrent uneasinesses of hunger and thirst are providential provisions for our survival because they determine our wills toward eating and drinking. Since each uneasiness is experienced as an obstacle to the achievement of happiness, desire for its removal determines the will unless there is another source of uneasiness that overcomes it. [Essay II xxi 34-36]

According to Locke, the simple ideas of pleasure and pain invariably accompany all of our other perceptions, as the delight or uneasiness we experience along with contemplation of every sensory and reflective object of thought. This is a significant provision for the conduct of life, since our native desire for happiness and aversion to misery are thereby guided in determining our wills toward certain thoughts and actions and away from others. This is why we eat good-tasting food and don't burn ourselves on hot stoves.

What is more, Locke supposed that our experience of varying degrees of pleasure and pain not only serves us well in this life but also engenders our hope of a better life hereafter. [Essay II vii 1-6] It even provides us with some confidence about the real existence of the external world, since the immediate perception of pleasure and pain is the kind of experience whose involuntary insistence communicates most surely its origin in a source outside ourselves. [Essay IV xi 6-8]

It is from successive compounding of these simple ideas, Locke supposed, that we frame the complex ideas of human passions of every sort-love, hate, desire, joy, sorrow, hope, fear, despair, anger, and envy are all modes of pleasure and pain, considered together with notions about the specific circumstances of their origin. [Essay II xx]

On this account of human motivation, the practical efficacy of our morality of good and evil depends upon their perception as pleasure or pain. If it is to have any genuine motive force, moral value, like natural benefit, must ultimately be defined in terms of pleasure and pain. ["Of Ethics in General" 7-8]

Good and evil generally are to be considered nothing more than tendencies to produce pleasure and pain, Locke held, and moral good and evil are nothing other than special instances of this association, the reward and punishment artificially annexed by a powerful legislator as the consequences that follow from human actions by virtue of their conformity with or difference from the dictates of moral law. [Essay II xviii 5]

The central problem for Locke's hedonism is the human tendency toward a myopic appreciation of our own welfare. Since only present uneasiness can determine the will, the future moral consequences of our actions motivate us only through our present contemplation of the pleasure or pain that they will produce. All too often, our delight in an immediate pleasure or our satisfaction with the removal of an immediate pain override the motive force of remote future consequences. [Essay II xxi 59-64]

Pursuit of Happiness

The effort to deal with this problem was central to the second-edition account of human volition. Locke withdrew his earlier claim that "the greater Good is that alone which determines the will" in favor of the view that the uneasiness of desire is the proximate cause of every volition, and this requires some careful explanation. [Essay II xxi 42]

For readers who might well have preferred the high ground of the earlier doctrine, Locke emphasized that contemplation of an absent future good can still have motive force, but insisted that it can do so only through the mediation of the present uneasiness it induces in us.

The difficulty, then, lies in the failure of a perfect proporionality between the felt uneasiness and the greatness of the contemplated good: if it were not so, then mere contemplation of "the infinite eternal joys of Heaven" would invariably motivate us to act only in the achievement of that long-term goal, whereas in fact it is commonly overcome by some trifling yet immediate desire. [Essay II xxi 31-38]

Locke certainly agreed that pursuit of lasting happiness is more important to human life than merely momentary pleasure, but he noted how easily it can get lost among the welter of daily human motives. Pain being felt in the moment always contributes to our present misery, while contemplation of the deferred gratification we hope to achieve from future rewards is not always experienced as present happiness. The onslaught of desires for the more immediate needs of life, as a matter of practical necessity and acquired habit, commonly leaves little room for concern about remotely future goods. [Essay II xxi 43-45]

The natural tendency toward determination of the will by the most pressing immediate uneasiness is not inevitable, Locke proposed, since human agents possess the further capacity "to suspend the execution and satisfaction" of their desires. By providing ample opportunity for reflection upon the relative importance of each desire, this suspencsion of the will in deliberation is vital for the proper conduct of human life. [Essay II xxi 46-47]

Like someone who stands still, consults a guide, and then proceeds, we suspend volition, examine our desires, and permit our wills to be determined by the result. The free agent's ability to distinguish real from imagined happiness by due examination therefore rests squarely upon the capacity to suspend the satisfaction of immeditate desires.

Once we have undertaken the appropriate deliberation during this period of suspension, Locke held, we have done our duty, and it is right to act upon the volition to which our wills are determined as a result. [Essay II xxi 51-53]

Here Locke distinguished two ways in which a motivating uneasiness may arise in us: either through the immediate effect of an external cause, or through the more lasting consequences to be gained through deliberate contemplation of our future rewards. Moral failure, then, results less often from individual perversity than from excessive haste, which may prevent us from appreciating the present conditions for our future happiness or misery.

(Thus, for example, the abstemious Locke supposed that no one would drink too much if the unpleasant future effects of over-indulgence were experienced in the present as vividly as the immediate pleasure of imbibing.) So long as the extent, degree, and certainty of future consequences are not duly evaluated in the suspended state of careful deliberation, we will commonly act in ways that confound rather than produce the happiness we all naturally seek.

Securing our genuine, long-term welfare requires cultivation of the habit of deliberative judgment, during which we focus upon the likelihood of suffering the punishments or gaining the rewards attached to contemplated actions by the moral law. [Essay II xxi 57-70] ©1999-2002 Garth Kemerling.Last modified 27 October 2001.Questions, comments, and suggestions may be sent to:

Moral Agents

Three years after the Essay was published, Locke's friend William Molyneux wrote from Ireland with several suggestions. Although he greatly admired Locke's achievment, Molyneux proposed recasting it as a scholastic textbook on logic and metaphysics, with a supplementary volume dealing more fully with human action and morality. Specifically, Molyneux invited his friend to "Insist more particularly and at Large on ?terna Veritates and the Principium Individuationis." [Corr. 1609] Locke and Molyneux clearly shared a conviction that the attribution of moral responsibility and the justice of moral sanctions depends upon the persistent identity of the moral agent.

But in the Essay's first edition, Locke had pointed out two significant difficulties: First, of course, he denied that the personal identity of moral agents can be known innately. [Essay I iii 3-5] Secondly, he had argued that Cartesian dualism cannot adequately ground personal identity on the substantial identity of the soul, the body, or their composite. [Essay II i 11-12] Now Molyneux demanded that Locke provide an account of his own, and a few months later, he had prepared a draft of a new chapter (what would become II xxvii) for the second edition of the Essay. [Corr. 1655]

Sortal Identity

The basic notion of identity (and diversity) arises from the simple fact that no two things of the same kind can co-exist in the same place; extended through time, this entails that every individual must have a spatio-temporal history that is unique among others of its kind. [Essay II xxvii 1] Thus, Locke held, From what has been said, 'tis easy to discover, what is so much enquired after, the principium Individuationis, and that 'tis plain is Existence it self, which determines a Being of any sort to a particular time and place incommunicable to two Beings of the same kind.

[Essay II xxvii 3] Of course, we can make intuitive judgments of identity and diversity only if our ideas of the thing or things involved are clear, but the crucial insight of Locke's theory of identity is that it must be applied sortally, with respect to things belonging to a common kind. No matter what in particular happens to constitute the very existence of a thing as it is conceived under a sortal term and the complex idea it signifies, Locke supposed, the identity of that thing through time just is its continued existence as a thing of this sort.

[Essay II xxvii 28-29] On Locke's view, then: God continuously exists unchanged in all places and at all times; each finite spirit begins to exist and continues to exist distinctly from every other thinking thing; particular bodies must each have their own unique spatio-temporal histories; non-substantial modes and relations typically persist as features of one or more substances; and even composite objects derive their identity from the collection of things that constitute them. Although any of these varieties of "thing" may coexist with any of the others, each uniquely occupies its own "space" within the sort of which it is a member. [Essay II xxvii 2-3]

Although living things similarly comprise a collection of material particles, Locke carefully noted, their persistence through time depends less upon the preservation of the same collection than upon the pattern of organization it exhibits at different times. The full-grown horse is the same animal as the colt of a few years hence, and the mighty oak is the same tree as the sapling of a century ago, even though the particular bits of matter each includes are distinct.

What matters in such cases, according to Locke, is the continuous (vegetable or animal) "Life" of the thing, the organization of material parts in a way that creates and preserves its most characteristic functions in the world. [Essay II xxvii 3-5]

The identity of an individual human being ("Man") rests upon exactly the same foundation in Locke's theory. Human beings should be defined not by their rationality (else we be forced to call the rational Brazilian parrot a man) nor by their presumed annexation to an immaterial soul (else the same man may exist in different centuries) but rather as living animals of a particular species, with its characteristic structure and function.

But then human identity is just animal identity: at any one time, there is a collection of material parts organized in a fashion suitable for the support of human life, and that life persists through the continuation of this pattern of organization even when its particular material constituents are successively annexed and removed. I am the same human being as my mother's first-born child, despite the obvious alterations of a half-century, because my "life"-understood as an ongoing principle of organization-has been continuous. [Essay II xxvii 6-8]

Personal Identity

The person is something else entirely. Locke's account of the demonstrability of morality relied upon an abstract conception of the moral agent, or "the Moral Man," understood simply in terms of its functions in contemplating and performing actions-"a corporeal rational Being." [Essay III xi 16] But that is precisely the definition Locke now provides for the notion of the "Self" or "Person:" It is a Forensick Term appropriating Actions and their Merit; and so belongs only to intelligent Agents capable of a Law, and Happiness and Misery.

[Essay II xxvii 26] But since the person is a different kind of thing, the criteria for the identity of a particular person through time will also be different from those that apply for substances, composites, and even living human beings.

Having defined the person in terms of its function rather than by reference to its underlying nature, Locke explicitly maintained that the identity of a conscious person is independent of the identity of whatever substance (or substances) happen to compose it at any time.

[Essay II xxvii 9-10] This view has some clear advantages in the effort to provide a secure foundation for moral reasoning: a non-substantial account personal identity renders morally irrelevant all metaphysical disputes about human nature, since the continued existence of the same substance-material or immaterial-is neither necessary nor sufficient for that of the moral agent.

[Essay II xxvii 24-25] In particular, Locke took great pains in showing that the Cartesian account of human nature, as an immaterial thinking substance existing in uneasy alliance with a differentiated portion of the material universe, is inadequate for the allocation of just punishment to the same moral agent who commits an immoral act. Several of Locke's notorious "puzzle cases" are intended precisely to undermine any attempt at a Cartesian explanation of moral accountability.

[Essay II xxvii 10-14] The other "puzzle cases" illustrate the independence of personal identity from the animal identity of any human organism. Although "same person" and "same human being" are sometimes used interchangeably in ordinary discourse, Locke noted, they are philosophically distinct. One and the same human being-while awake and while asleep-could participate in conscious lives that were as completely distinct from each other in the moral sense as are the distinct lives of identical twins. Even the legal tradition preserves this point by declining to punish a human being for actions performed while insane, since these crimes were, for all moral purposes, committed by a different person.

[Essay II xxvii 15-20] A morally adequate position must somehow account for personal identity without reference to either an immaterial soul or a living body. Consciousness and Accountability According to Locke, an appropriate account of personal identity must arise from careful analysis of the concept of the person. Since self-conscious awareness invariably accompanies all human thought, it alone can both distinguish the self from every other thinking thing in the present and preserve its identity through time.

This being premised to find wherein personal Identity consists, we must consider what Person stands for; which, I think, is a thinking intelligent Being, that has reason and reflection, and can consider it self as it self, the same thinking thing in different times and places; which it does only by that consciousness, which is inseparable from thinking, and as it seems to me essential to it.

[Essay II xxvii 9] Since only consciousness of pleasure and pain can support both desire for one's own welfare and accountability for one's own actions, it is by consciousness alone that the self appropriates those present or past actions for which it now or in the future justly deserves to be punished or rewarded.

[Essay II xxvii 23, 26] Consciousness is both a necessary and a sufficient condition for a morally vital sense of personal identity. It is necessary because no past thought or action was truly mine unless I now self-consciously appropriate it to myself; and from this it follows that I cannot now be justly punished as the agent who committed some past action unless I am conscious of having performed that action myself.

[Essay II xxvii 18-20] It is sufficient because consciousness unites temporally distinct thoughts and actions from past, present, and future into a single person; since I can now harbor concern for the happiness or misery of the future self that would justly suffer punishment for my present transgressions, deliberation about those consequences are a relevent force in motivating my present conduct.

[Essay II xxvii 15-18] It all comes down to this: For as far as any intelligent Being can repeat the Idea of any past Action with the same consciousness it had of it at first, and with the same consciousness it has of any present Action; so far it is the same personal self. For it is by the consciousness it has of its present Thoughts and Actions, that it is self to it self now, and so will be the same self as far as the same consciousness can extend to Actions past or to come.

[Essay II xxvii 10] One difficulty with Locke's explanation is that the self-conscious awareness he holds to be constituitive of personal identity is, by its very nature, accessible only to the individual self. It follows that third-person judgments of personal identity are systematically liable to error. For the allocation of punishment and reward, human judicatures must rely upon the presumed association of conscious personal identity with that of a living human body. Although it regards this presumption as defeasible in cases of madness or somnambulism, the civil law rightly focusses upon what it can prove rather than upon what it can only suppose to the contrary.

[Essay II xxvii 19-22] If the security videos convince a jury that this living human body is the one who pointed a gun at the teller, then my protestation that I have no conscious awareness of having the bank is unlikely to prevent my conviction in court, unless I can provide some over-riding evidence of my loss of consciousness.

Locke seems to have been little concerned with the difficulty of proposing an explanation of moral accountability that rests upon a criterion of personal identity that cannot be reliably applied by other observers. The eternal sanctions for obedience to divine law, he firmly believed, will be distributed ultimately by a deity to whom "the secrets of all Hearts" are perfectly accessible: although human courts may err, God will not. Besides, the most vital role of Locke's account is to link obligation and motivation in the deliberative process that takes place entirely in the first-person mode: it is my own present belief that I will be punished later that disinclines me to misbehave now. [Essay II xxvii 25-26]

The Natural World

In addition to the vital awareness of God and morality that guides proper action, practical human knowledge requires some familiarity with the physical world whose features so clearly limit our capacity for happiness. Thus, Locke devoted careful attention to our use of the faculty of sensory perception, the passive ability to receive ideas from the external world by means of our sensory organs.

The simple ideas acquired by attending to these mechanical operations are the first components of all human thought. [Essay II ix 1-6] Although sensitive knowledge is strictly limited in its scope and reliability, Locke held that the testimony of sensory experience, lying as it does entirely outside our voluntary control, provides all the evidence we can have-and all the evidence we need-of the existence, nature, and operation of physical objects.

[Essay IV xi 2-6] Space and Time Since the simple idea of space is derived from both visual and tactile perception, it is conceived as the three-dimensional separation of distinct bodies. Its simple modes include both units of spatial measurement and the geometrical figures. [Essay II xiii 2-6] Because space is conceived as continuous extension with inseparable and immoveable parts, Locke emphatically denied the Cartesian identification of space with body. [Essay II xiii 13-17]

This has significant consequences, including the possibility of space without any body in it-the vacuum so decried by Cartesian natural philosophy. On Locke's view, the argument is clear: since the ideas of space and body are distinct, the possibility of one existing without the other is evident, unless our opinions are driven by theoretical prejudice. [Essay II xiii 21-26] The further idea of place is a simple mode of space as specified by reference to fixed points or objects within some frame of reference, chosen for its convenience in serving human purposes.

[Essay II xiii 7-10] Time yields to a similar pattern of analysis. Reflection on the succession of ideas in the mind, especially during our experience of the motion of external objects, gives rise to the simple idea of duration, from which in turn we derive all of the simple modes of time and temporal measurments. [Essay II xiv 1-8] The idea of time itself is just that of a determinate length of this duration, measured across non-contemporaneous intervals by reference to the presumed regularity of periodic natural movements, such as the rotation and orbit of the earth in relation to the sun.

[Essay II xiv 17-23] Once established upon the basis of our experiences, these measurments of time can be applied beyond the limits of that experience, or even beyond the finite boundaries of the original motions themselves. Once we know how much time "a year" is, by observation of the seasonal changes produced during a single orbit of the earth, we can without difficulty consider the extent of time that occurred before the sun or earth existed.

[Essay II xiv 24-30] There is, then, a systematic analogy between spatial and temporal ideas for Locke: Both are conceived in limited experiences, yet can be applied to infinite expansion or duration. Space and duration are continuous and undifferentiated, yet both permit the designation of place and time in relation to fixed points of reference. Finally, both space and time are infinitely divisible, even though their parts are inseparable. Together, they provide a framework for organizing our experience, within three-dimensional space and linear time.

[Essay II xv 1-12] Both space and time are subject to quantification. Beginning with the simple idea of unity, each of us repeats and compounds it mentally in order to conceive the simple modes of number, each of which is so clear and distinct as to ground demonstrable knowledge of mathematics. [Essay II xvi 1-8] What is more, Locke held that this process of compounding is, in principle, unlimited, and our awareness that the process could be repeated indefinitely provides us with a clear idea of infinity.

[Essay II xvii 1-5] Although we naturally and correctly apply this idea to our conceptions of space and time, Locke noted that we have no positive notion from experience of either infinite duration or infinite extension. Knowing that there is no end of the counting process is not the same as having an independent, positive idea of infinity.

[Essay II xvii 9-15]

Bodies

Within the spatio-temporal framework, what we experience are physical objects, or bodies. Unlike the Cartesians, Locke distinguished sharply between the ideas of space and body: both involve extension, but bodies have the additional feature of solidity. Derived from our tactile experience of the physical world, the simple idea of solidity is that of mutual impenetrability-where space is filled by one body, another cannot enter.

This idea is different both from the simple idea of extension and from that of hardness, but solidity alone is an inseparable essential feature of all bodies. [Essay II iv 1-6] The experience of changes in the relative place of distinct bodies with respect to each other through time gives rise to the idea of motion, and this is another of our primary ideas of bodies.

In practice, we commonly distinguish different bodies by moving them apart from each other spatially. [Essay II xiii 7-11] But Locke emphasized that motion is only an activity of bodies, not truly a part of their essence. [Essay II i 10]

Thus, the most basic features of body are extension, solidity, and mobility. When determinate qualities of these determinables (along with the ideas of the powers of causal interaction) are added to the idea of substance in general, we form the complex idea of a physical object. [Essay II xxiii 3-10] Although Locke believed our knowledge of material substances to be strictly limited by the bounds of our sensory capacities, he also supposed that the experiential awareness of bodies that we are capable of is adequate for our practical needs for living successfully in a material world. [Essay II xxiii 11-16]

Although we are incapable of demonstrative knowledge of the substantial natures and causal powers that operate in the natural world, on Locke's view, we can achieve probable knowledge based upon our sensory observations. The corpuscularian hypothesis offers our most coherent account of the occurrence of observable sensible qualities.

[Essay IV iii 16] The insensible, minute particles of material substance are the real essences whose causal interactions, in ways unknown to us, produce all of the observable qualities and powers that come to be included in our abstract ideas of them, their nominal essences.

[Essay III iii 17-18] Analogical reasoning from familiar macroscopic events enables us at least to imagine how unobservably small corpuscles might interact in ways that produce the sensible qualities and powers of bodies that are visible to us. [Essay IV xvi 12]

Thus, our knowledge of the natural world and its operations is reliable, adequate, and sufficient for our practical needs, yet it is strictly limited. Efforts to achieve a more systematic degree of certainty in this realm are not only bound to fail but also tend to require a blind assent to abstract principles, which can only confirm us in error rather than lead us to truth. [Essay IV xii 4-5] Here, as elsewhere in the development of the human understanding, Locke believed it vital to recognize and to respect our limitations.

Causality

Our ignorance of nature extends to the operations as well as to the natures of bodies. The constancy of our observations of simple interactions among physical objects, for example, leads us to suppose that there must be some genuine degree of causal regularity in nature itself, this awareness can never reach to more than the level of probable assurance, since the causes themselves remain unknown to us. [Essay IV xvi 6] The ideas of cause and effect derive from our observation that changes appear to occur as the result of other changes. What we identify as capable of producing such a change, we call the cause, and the change it produces, the effect.

Within this general conceptual frame, Locke distinguished between the creation of something entirely new, the generation of a natural being from its own internal development, the making of an artificial being, and the alteration of things by substituting one quality from another.

[Essay II xxvi 1-2] In none of these instances, however, are we fully aware of the nature of the causal process itself.

Such assurance of causal regularity as we can achieve derives solely from the observed recurrence of patterns in our sensory experience, and when the experiences are confirmed with universality, our confidence inevitably grows. Thusly encouraged, we use analogical reasoning to generate causal hypothesis about connections among things and events whose operations lie wholly beyond our experience. [Essay IV xvi 6-7]

But such suppositions can never be certain. Our ignorance of the primary qualities of bodies and of the means by which they produce observable secondary qualities make it impossible for us to demonstrate the coexistence of qualities in a common subject, even when we have observed it frequently enough to incorporate putative causal powers within our nominal essences of substances of a particular sort. [Essay IV vi 6-9]

So long as our knowledge of bodies is dervied from the observable qualities of bodies, in ignorance of their internal features and operations, we can have no certain universal knowledge of the material world. Without doubting the genuine causal efficacy of particular substances, Locke believed it impossible for us to know of it. Observational regularity is the best we can do, and it must be adequate for our needs, even though we remain forever incapable of comprehending the true structure of reality. [Essay IV vi 10-11]

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Category	Western Philosophy
Writer	Garth Kemerling
The language of the book	English
print year	1404