Locke’s Essay: Book III

John Locke Essay Concerning Human Understanding, Final Edition, 1699 (Original 1690).


Locke critiques the common practice of reasoning about reality as if words somehow reliably corresponded to reality when they dont. He advocates bearing in mind the lack of exactness, anticipating George Boole’s Laws of Thought.

He also has some advice on rhetoric.


1. Words are sensible Signs, necessary for Communication of Ideas.

2. Words, in their immediate Signification, are the sensible Signs of his Ideas who uses them.

5. Secondly, to the Reality of Things.

Because men would not be thought to talk barely of their own imagination, but of things as really they are; therefore they often suppose the WORDS TO STAND ALSO FOR THE REALITY OF THINGS.

6. Words by Use readily excite Ideas of their objects.

Concerning words, also, it is further to be considered:

First, that they being immediately the signs of men’s ideas, and by that means the instruments whereby men communicate their conceptions, and express to one another those thoughts and imaginations they have within their own breasts; there comes, by constant use, to be such a connexion between certain sounds and the ideas they stand for, that the names heard, almost as readily excite certain ideas as if the objects themselves, which are apt to produce them, did actually affect the senses. Which is manifestly so in all obvious sensible qualities, and in all substances that frequently and familiarly occur to us.

8. Their Signification perfectly arbitrary, not the consequence of a natural connexion.

Words, by long and familiar use, as has been said, come to excite in men certain ideas so constantly and readily, that they are apt to suppose a natural connexion between them. But that they signify only men’s peculiar ideas, and that BY A PERFECT ARBITRARY IMPOSITION, is evident, in that they often fail to excite in others (even that use the same language) the same ideas we take them to be signs of: and every man has so inviolable a liberty to make words stand for what ideas he pleases, that no one hath the power to make others have the same ideas in their minds that he has,


Berkeley critiques this aspect.

1. The greatest Part of Words are general terms.

All things that exist being particulars, it may perhaps be thought reasonable that words, which ought to be conformed to things, should be so too,—I mean in their signification: but yet we find quite the contrary. The far greatest part of words that make all languages are general terms: which has not been the effect of neglect or chance, but of reason and necessity.

2. That every particular Thing should have a Name for itself is impossible.

6. How general Words are made.

The next thing to be considered is,—How general words come to be made. For, since all things that exist are only particulars, how come we by general terms; or where find we those general natures they are supposed to stand for? Words become general by being made the signs of general ideas: and ideas become general, by separating from them the circumstances of time and place, and any other ideas that may determine them to this or that particular existence. By this way of abstraction they are made capable of representing more individuals than one; each of which having in it a conformity to that abstract idea, is (as we call it) of that sort.

While this differs from Berkeley, it is not clear to me that it is necessarily a difference that makes a difference.

7. Shown by the way we enlarge our complex ideas from infancy.

But, to deduce this a little more distinctly, it will not perhaps be amiss to trace our notions and names from their beginning, and observe by what degrees we proceed, and by what steps we enlarge our ideas from our first infancy. There is nothing more evident, than that the ideas of the persons children converse with (to instance in them alone) are, like the persons themselves, only particular. The ideas of the nurse and the mother are well framed in their minds; and, like pictures of them there, represent only those individuals. The names they first gave to them are confined to these individuals; and the names of NURSE and MAMMA, the child uses, determine themselves to those persons. Afterwards, when time and a larger acquaintance have made them observe that there are a great many other things in the world, that in some common agreements of shape, and several other qualities, resemble their father and mother, and those persons they have been used to, they frame an idea, which they find those many particulars do partake in; and to that they give, with others, the name MAN, for example. And thus they come to have a general name, and a general idea. Wherein they make nothing new; but only leave out of the complex idea they had of Peter and James, Mary and Jane, that which is peculiar to each, and retain only what is common to them all.

8. And further enlarge our complex ideas, by still leaving out properties contained in them.

By the same way that they come by the general name and idea of MAN, they easily advance to more general names and notions. For, observing that several things that differ from their idea of man, and cannot therefore be comprehended out under that name, have yet certain qualities wherein they agree with man, by retaining only those qualities, and uniting them into one idea, they have again another and more general idea; to which having given a name they make a term of a more comprehensive extension: which new idea is made, not by any new addition, but only as before, by leaving out the shape, and some other properties signified by the name man, and retaining only a body, with life, sense, and spontaneous motion, comprehended under the name animal.

9. General natures are nothing but abstract and partial ideas of more complex ones.

17. Supposition, that Species are distinguished by their real Essences useless.

19. Essences ingenerable and incorruptible.

That such abstract ideas, with names to them, as we have been speaking of are essences, may further appear by what we are told concerning essences, viz. that they are all ingenerable and incorruptible. Which cannot be true of the real constitutions of things, which begin and perish with them.

20. Recapitulation.

To conclude. This is that which in short I would say, viz. that all the great business of GENERA and SPECIES, and their ESSENCES, amounts to no more but this:—That men making abstract ideas, and settling them in their minds with names annexed to them, do thereby enable themselves to consider things, and discourse of them, as it were in bundles, for the easier and readier improvement and communication of their knowledge, which would advance but slowly were their words and thoughts confined only to particulars.

For example, scholastic biology includes a concept of species that real creatures do not always conform to. (It is just a convenient over-simplification or ‘myth’.)


This is largely about rhetoric, and covers both intentional and unintentional abuse.

1. Woeful abuse of Words.

Besides the imperfection that is naturally in language, and the obscurity and confusion that is so hard to be avoided in the use of words, there are several WILFUL faults and neglects which men are guilty of in this way of communication, whereby they render these signs less clear and distinct in their signification than naturally they need to be.

2. First, Words are often employed without any, or without clear Ideas.

FIRST, In this kind the first and most palpable abuse is, the using of words without clear and distinct ideas; or, which is worse, signs without anything signified. Of these there are two sorts:—

  1. Some words introduced without clear ideas annexed to them, even in their first original.
  2. Other Words, to which ideas were annexed at first, used afterwards without distinct meanings.
  3. This occasioned by men learning Names before they have the Ideas the names belong to.

Secondly Unsteady Application of them.

SECONDLY, Another great abuse of words is INCONSTANCY in the use of them.

As when we fail to distinguish between the mathematical idea of a line (a simple idea) and the physical idea (an abstraction).

Thirdly, Affected Obscurity, as in the Peripatetic and other sects of Philosophy

  1. Logic and Dispute have much contributed to this.

This is unavoidably to be so, where men’s parts and learning are estimated by their skill in disputing. And if reputation and reward shall attend these conquests, which depend mostly on the fineness and niceties of words, it is no wonder if the wit of man so employed, should perplex, involve, and subtilize the signification of sounds, so as never to want something to say in opposing or defending any question; the victory being adjudged not to him who had truth on his side, but the last word in the dispute.

Fourthly, by taking Words for Things.

Fifthly, by setting them in the place of what they cannot signify.

The Cause of this Abuse, a supposition of Nature’s working always regularly, in setting boundaries to Species.

That which I think very much disposes men to substitute their names for the real essences of species, is the supposition before mentioned, that nature works regularly in the production of things, and sets the boundaries to each of those species, by giving exactly the same real internal constitution to each individual which we rank under one general name. Whereas any one who observes their different qualities can hardly doubt, that many of the individuals, called by the same name, are, in their internal constitution, as different one from another as several of those which are ranked under different specific names.

For example, it is convenient for biologists to define a term ‘species’, as long as they don’t think that nature has to confirm to their definitions.

This Abuse contains two false Suppositions.

But however preposterous and absurd it be to make our names stand for ideas we have not, or (which is all one) essences that we know not, it being in effect to make our words the signs of nothing; yet it is evident to any one who ever so little reflects on the use men make of their words, that there is nothing more familiar. When a man asks whether this or that thing he sees, let it be a drill, or a monstrous foetus, be a MAN or no; it is evident the question is not, Whether that particular thing agree to his complex idea expressed by the name man: but whether it has in it the real essence of a species of things which he supposes his name man to stand for. In which way of using the names of substances, there are these false suppositions contained:—

First, that there are certain precise essences according to which nature makes all particular things, and by which they are distinguished into species. That everything has a real constitution, whereby it is what it is, and on which its sensible qualities depend, is past doubt: but I think it has been proved that this makes not the distinction of species as WE rank them, nor the boundaries of their names.

Secondly, this tacitly also insinuates, as if we had IDEAS of these proposed essences. For to what purpose else is it, to inquire whether this or that thing have the real essence of the species man, if we did not suppose that there were such a specifick essence known? Which yet is utterly false. And therefore such application of names as would make them stand for ideas which we have not, must needs cause great disorder in discourses and reasonings about them, and be a great inconvenience in our communication by words.

Sixthly, by proceeding upon the supposition that the words we use have a certain and evident Signification which other men cannot but understand.


He that hath names without ideas, wants meaning in his words, and speaks only empty sounds. He that hath complex ideas without names for them, wants liberty and dispatch in his expressions, and is necessitated to use periphrases. He that uses his words loosely and unsteadily will either be not minded or not understood. He that applies his names to ideas different from their common use, wants propriety in his language, and speaks gibberish. And he that hath the ideas of substances disagreeing with the real existence of things, so far wants the materials of true knowledge in his understanding, and hath instead thereof chimeras.


First Remedy: To use no Word without an Idea annexed to it.

Second Remedy: To have distinct, determinate Ideas annexed to Words, especially in mixed Modes

Third Remedy: To apply Words to such ideas as common use has annexed them to.

Fourth Remedy: To declare the meaning in which we use them.

Fifth Remedy: To use the same word constantly in the same sense.

Dave Marsay

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