Locke published An Essay Concerning Human Understanding in 1689. In Book II of the treatise, Locke argues that all knowledge is derived from sensation and reflection. This type of epistemology is known as empiricism.
Empiricism contradicts Descartes’ rationalism. Descartes believed that the senses could not serve as a foundation for the superstructure of knowledge. All perceptions, according to Descartes, might be illusions, like those in dreams. Instead, one must form knowledge based upon principles derived purely from reason – the first such principle being “Cogito ergo sum.”
Locke counters Descartes by asserting that all knowledge is derived from sensation and reflection. Sensation is the sum of all observations made of external things, and reflection is the sum of all observations made of the operations within one’s own mind. To support his claim, Locke adduces the relative lack of reasoning manifested by infants. Their reasoning capabilities increase inasmuch as they are exposed to new experiences and begin to contemplate the mind’s handling and manipulation of those experiences.
As another proof, Locke asserts that no man can imagine a simple idea that he has not already experienced. For example, one could not imagine the experience of seeing colors if one was blind from birth.
In the consideration of physical objects, Locke asserts that all objects possess primary qualities – such as extension, form, motion, and number. These primary qualities have the power to produce secondary qualities within us – such as color, taste, sound, and odor. Thus, these secondary qualities do not exist within the objects, but rather exist in our minds.
This chain of reasoning reminded me of Protagoras’ relativism that was outlined in Plato’s Theaetetus and Aristotle’s Metaphysics. To briefly review Protagoras’ position, he states that “man is the measure of all things.” In other words, if one man perceives water as cold, then the water is cold. If another man perceives the same water as hot, then the water is hot. Both Plato and Aristotle refute Protagoras’ relativism by demonstrating that it violates the principle of non-contradiction – the same water cannot be cold and not-cold at the same time. However, I believe that Locke’s distinction of primary and secondary qualities affords a defense for Protagoras. Referring back to the water example, coldness and hotness do not exist in the water. The water has the power to produce the sensation of coldness and hotness, but it is neither cold nor hot in itself.
Perhaps it will be easier to understand if we consider another example. Consider the nature of fire. Clearly pain does not exist in the fire itself, but we perceive pain when we touch a flame. Pain therefore is a secondary quality of fire, not a primary quality. Fire has the power to create the sensation of pain within us, just as water has the power to create the sensation of coldness within us.
In chapter 27, Locke presents his theory regarding personal identity. He asserts that personal identity rests solely in the continuity of consciousness. Locke does not believe, as Descartes believes, that the soul is the essence of personal identity. Locke poses several absurd conclusions that result from Descartes’ position. For example, if the soul is the essence of personal identity, then one soul may inhabit the bodies of several different people. When one man is asleep, and unconscious, the soul may travel to another body; and therefore Descartes would incorrectly conclude that two different people are two identical people.
Furthermore, if the continuity of the body is the essence of personal identity, then personal identity would change every moment; for particles of our bodies are separating from us, and new particles are attaching themselves to us every instant. This is just a brief summary of Locke’s thoughts concerning personal identity. I highly recommend anyone who is interested in examining Locke’s ideas about personal identity to read chapter 27 in Book II of this treatise.
“These two, I say, viz. external material things, as the objects of SENSATION, and the operations of our own minds within, as the objects of REFLECTION, are to me the only originals from whence all our ideas take their beginnings.”
“I confess myself to have one of those dull souls, that doth not perceive itself always to contemplate ideas; nor can conceive it any more necessary for the soul always to think, than for the body always to move: the perception of ideas being (as I conceive) to the soul, what motion is to the body; not its essence, but one of its operations. And therefore, though thinking be supposed never so much the proper action of the soul, yet it is not necessary to suppose that it should be always thinking, always in action. That, perhaps, is the privilege of the infinite Author and Preserver of all things, who “never slumbers nor sleeps;” but is not competent to any finite being, at least not to the soul of man. We know certainly, by experience, that we sometimes think; and thence draw this infallible consequence,- that there is something in us that has a power to think. But whether that substance perpetually thinks or no, we can be no further assured than experience informs us. For, to say that actual thinking is essential to the soul, and inseparable from it, is to beg what is in question, and not to prove it by reason;- which is necessary to be done, if it be not a self-evident proposition. But whether this, “That the soul always thinks,” be a self-evident proposition, that everybody assents to at first hearing, I appeal to mankind. It is doubted whether I thought at all last night or no. The question being about a matter of fact, it is begging it to bring, as a proof for it, an hypothesis, which is the very thing in dispute: by which way one may prove anything, and it is but supposing that all watches, whilst the balance beats, think, and it is sufficiently proved, and past doubt, that my watch thought all last night. But he that would not deceive himself, ought to build his hypothesis on matter of fact, and make it out by sensible experience, and not presume on matter of fact, because of his hypothesis, that is, because he supposes it to be so; which way of proving amounts to this, that I must necessarily think all last night, because another supposes I always think, though I myself cannot perceive that I always do so.
But men in love with their opinions may not only suppose what is in question, but allege wrong matter of fact. How else could any one make it an inference of mine, that a thing is not, because we are not sensible of it in our sleep? I do not say there is no soul in a man, because he is not sensible of it in his sleep; but I do say, he cannot think at any time, waking or sleeping: without being sensible of it. Our being sensible of it is not necessary to anything but to our thoughts; and to them it is; and to them it always will be necessary, till we can think without being conscious of it.”
“I grant that the soul, in a waking man, is never without thought, because it is the condition of being awake. But whether sleeping without dreaming be not an affection of the whole man, mind as well as body, may be worth a waking man’s consideration; it being hard to conceive that anything should think and not be conscious of it. If the soul doth think in a sleeping man without being conscious of it, I ask whether, during such thinking, it has any pleasure or pain, or be capable of happiness or misery? I am sure the man is not; no more than the bed or earth he lies on. For to be happy or miserable without being conscious of it, seems to me utterly inconsistent and impossible. Or if it be possible that the soul can, whilst the body is sleeping, have its thinking, enjoyments, and concerns, its pleasures or pain, apart, which the man is not conscious of nor partakes in,- it is certain that Socrates asleep and Socrates awake is not the same person; but his soul when he sleeps, and Socrates the man, consisting of body and soul, when he is waking, are two persons: since waking Socrates has no knowledge of, or concernment for that happiness or misery of his soul, which it enjoys alone by itself whilst he sleeps, without perceiving anything of it; no more than he has for the happiness or misery of a man in the Indies, whom he knows not. For, if we take wholly away all consciousness of our actions and sensations, especially of pleasure and pain, and the concernment that accompanies it, it will be hard to know wherein to place personal identity.”
“They make the soul and the man two persons, who make the soul think apart what the man is not conscious of. For, I suppose nobody will make identity of persons to consist in the soul’s being united to the very same numercial particles of matter. For if that be necessary to identity, it will be impossible, in that constant flux of the particles of our bodies, that any man should be the same person two days, or two moments, together.”
“It is the affectation of knowing beyond what we perceive, that makes so much useless dispute and noise in the world.”
“I think it is not possible for any man to imagine any other qualities in bodies, howsoever constituted, whereby they can be taken notice of, besides sounds, tastes, smells, visible and tangible qualities. And had mankind been made but with four senses, the qualities then which are the objects of the fifth sense had been as far from our notice, imagination, and conception, as now any belonging to a sixth, seventh, or eighth sense can possibly be;- which, whether yet some other creatures, in some other parts of this vast and stupendous universe, may not have, will be a great presumption to deny. He that will not set himself proudly at the top of all things, but will consider the immensity of this fabric, and the great variety that is to be found in this little and inconsiderable part of it which he has to do with, may be apt to think that, in other mansions of it, there may be other and different intelligent beings, of whose faculties he has as little knowledge or apprehension as a worm shut up in one drawer of a cabinet hath of the senses or understanding of a man.”
“If any one ask me, What this solidity is, I send him to his senses to inform him. Let him put a flint or a football between his hands, and then endeavour to join them, and he will know. If he thinks this not a sufficient explication of solidity, what it is, and wherein it consists; I promise to tell him what it is, and wherein it consists, when he tells me what thinking is, or wherein it consists; or explains to me what extension or motion is, which perhaps seems much easier. The simple ideas we have, are such as experience teaches them us; but if, beyond that, we endeavour by words to make them clearer in the mind, we shall succeed no better than if we went about to clear up the darkness of a blind man’s mind by talking; and to discourse into him the ideas of light and colours.”
“Besides those before-mentioned primary qualities in bodies, viz. bulk, figure, extension, number, and motion of their solid parts; all the rest, whereby we take notice of bodies, and distinguish them one from another, are nothing else but several powers in them, depending on those primary qualities; whereby they are fitted, either by immediately operating on our bodies to produce several different ideas in us; or else, by operating on other bodies, so to change their primary qualities as to render them capable of producing ideas in us different from what before they did. The former of these, I think, may be called secondary qualities immediately perceivable: the latter, secondary qualities, mediately perceivable.”
“Take one in whom decrepit old age has blotted out the memory of his past knowledge, and clearly wiped out the ideas his mind was formerly stored with, and has, by destroying his sight, hearing, and smell quite, and his taste to a great degree, stopped up almost all the passages for new ones to enter; or if there be some of the inlets yet half open, the impressions made are scarcely perceived, or not at all retained. How far such an one (notwithstanding all that is boasted of innate principles) is in his knowledge and intellectual faculties above the condition of a cockle or an oyster, I leave to be considered. And if a man had passed sixty years in such a state, as it is possible he might, as well as three days, I wonder what difference there would be, in any intellectual perfections, between him and the lowest degree of animals.”
“Since the mind can sensibly put on, at several times, several degrees of thinking, and be sometimes, even in a waking man, so remiss, as to have thoughts dim and obscure to that degree that they are very little removed from none at all; and at last, in the dark retirements of sound sleep, loses the sight perfectly of all ideas whatsoever: since, I say, this is evidently so in matter of fact and constant experience, I ask whether it be not probable, that thinking is the action and not the essence of the soul? Since the operations of agents will easily admit of intention and remission: but the essences of things are not conceived capable of any such variation.”
“Things then are good or evil, only in reference to pleasure or pain. That we call good, which is apt to cause or increase pleasure, or diminish pain in us; or else to procure or preserve us the possession of any other good or absence of any evil. And, on the contrary, we name that evil which is apt to produce or increase any pain, or diminish any pleasure in us: or else to procure us any evil, or deprive us of any good. By pleasure and pain, I must be understood to mean of body or mind, as they are commonly distinguished; though in truth they be only different constitutions of the mind, sometimes occasioned by disorder in the body, sometimes by thoughts of the mind.”
“Pleasure operates not so strongly on us as pain.”
“Some ideas to the mind, like some motions to the body, are such as in certain circumstances it cannot avoid, nor obtain their absence by the utmost effort it can use. A man on the rack is not at liberty to lay by the idea of pain, and divert himself with other contemplations: and sometimes a boisterous passion hurries our thoughts, as a hurricane does our bodies, without leaving us the liberty of thinking on other things, which we would rather choose. But as soon as the mind regains the power to stop or continue, begin or forbear, any of these motions of the body without, or thoughts within, according as it thinks fit to prefer either to the other, we then consider the man as a free agent again.”
“Whether a man be at liberty to will which of the two he pleases, motion or rest? This question carries the absurdity of it so manifestly in itself, that one might thereby sufficiently be convinced that liberty concerns not the will. For, to ask whether a man be at liberty to will either motion or rest, speaking or silence, which he pleases, is to ask whether a man can will what he wills, or be pleased with what he is pleased with.”
“The uneasiness of desire determines the will. A little burning felt pushes us more powerfully than greater pleasures in prospect draw or allure.”
“It seems so established and settled a maxim, by the general consent of all mankind, that good, the greater good, determines the will, that I do not at all wonder that, when I first published my thoughts on this subject I took it for granted; and I imagine that, by a great many, I shall be thought more excusable for having then done so, than that now I have ventured to recede from so received an opinion. But yet, upon a stricter inquiry, I am forced to conclude that good, the greater good, though apprehended and acknowledged to be so, does not determine the will, until our desire, raised proportionably to it, makes us uneasy in the want of it. Convince a man never so much, that plenty has its advantages over poverty; make him see and own, that the handsome conveniences of life are better than nasty penury: yet, as long as he is content with the latter, and finds no uneasiness in it, he moves not; his will never is determined to any action that shall bring him out of it. Let a man be ever so well persuaded of the advantages of virtue, that it is as necessary to a man who has any great aims in this world, or hopes in the next, as food to life: yet, till he hungers or thirsts after righteousness, till he feels an uneasiness in the want of it, his will will not be determined to any action in pursuit of this confessed greater good; but any other uneasiness he feels in himself shall take place, and carry his will to other actions. On the other side, let a drunkard see that his health decays, his estate wastes; discredit and diseases, and the want of all things, even of his beloved drink, attends him in the course he follows: yet the returns of uneasiness to miss his companions, the habitual thirst after his cups at the usual time, drives him to the tavern, though he has in his view the loss of health and plenty, and perhaps of the joys of another life: the least of which is no inconsiderable good, but such as he confesses is far greater than the tickling of his palate with a glass of wine, or the idle chat of a soaking club. It is not want of viewing the greater good; for he sees and acknowledges it, and, in the intervals of his drinking hours, will take resolutions to pursue the greater good; but when the uneasiness to miss his accustomed delight returns, the great acknowledged good loses its hold, and the present uneasiness determines the will to the accustomed action; which thereby gets stronger footing to prevail against the next occasion, though he at the same time makes secret promises to himself that he will do so no more; this is the last time he will act against the attainment of those greater goods.”
“When we compare present pleasure or pain with future, (which is usually the case in most important determinations of the will,) we often make wrong judgments of them; taking our measures of them in different positions of distance. Objects near our view are apt to be thought greater than those of a larger size that are more remote. And so it is with pleasures and pains: the present is apt to carry it; and those at a distance have the disadvantage in the comparison. Thus most men, like spendthrift heirs, are apt to judge a little in hand better than a great deal to come; and so, for small matters in possession, part with greater ones in reversion.”
“Any action is rendered more or less pleasing, only by the contemplation of the end, and the being more or less persuaded of its tendency to it, or necessary connexion with it: but the pleasure of the action itself is best acquired or increased by use and practice. Trials often reconcile us to that, which at a distance we looked on with aversion; and by repetitions wear us into a liking of what possibly, in the first essay, displeased us. Habits have powerful charms, and put so strong attractions of easiness and pleasure into what we accustom ourselves to, that we cannot forbear to do, or at least be easy in the omission of, actions, which habitual practice has suited, and thereby recommends to us.”