Part I, Chapter 12: On the Remedy of the Confusion which arises in our Thoughts and in our Language, from the Confusion of Words
THE best way of avoiding the confusion of words which is found in common language, is to make a new language and new words, which may be attached only to those ideas which we wish them to represent. But for this purpose it is not necessary to make new sounds, since we may employ those which are already in use by regarding them as if they had no signification, in order that we may give them that which we may wish them to have, by designating, through other simple words,—about whose meaning there is no ambiguity,—the idea to which we wish to apply them; as, for instance, I wish to show that the soul is immortal, the word soul being equivocal, as we have shown it, may easily produce confusion from what I am about to say; so, in order to avoid this, I would regard the word soul as if it were a sound which had no meaning, and I would apply it solely to that within us which is the principle of thought, saying,—I call soul that which is the principle of thought within us.
This is what is called the definition of a name—definitio nominis—which geometers have turned to such good account, and which it is necessary to distinguish from the definition of a thing—definitio rei:—for in the definition of a thing, as, for instance, these—Man is a rational animal; Time is the measure of motion,—we leave to the terms which we define, as man, or time, their ordinary idea in which we maintain that other ideas are contained, as rational animal, or measure of motion; whereas, in the definition of a name, as we have already said, we regard only the sound, and afterwards, we determine that sound a sign of an idea, which we designate by other words.
It is necessary, also, to take care not to confound the definition of the name of which we here speak, with that of which some philosophers speak, who understand by it the explanation of that which a word signifies, according to the common custom of a language, or according to its etymology.
Of this we shall speak in another place. But here we regard, on the other hand, only the particular sense in which he who defines a word wishes it to be taken, in order that his thought may be clearly conceived, without considering at all whether others take it in the same sense. And from this it follows:—1st, That the definitions of names are arbitrary, and those of things are not so; for every sound being indifferent in itself, and, by nature, fitted equally well to express all sorts of ideas, I may be allowed, for my own use, and provided I forewarn others of it, to determine a sound to signify precisely a certain thing, without any mixture of anything else; but it is quite otherwise with the definitions of things, for it does not depend on the will of men that ideas should comprehend all that they would wish them to comprise; so that, if, in wishing to define, we attribute to these ideas something which they do not contain, we fall necessarily into error.
Thus, to give an example of the one and of the other, if, stripping the word parallelogram of all signification, I apply it to signify a triangle, this is allowable, and I do not commit any error, provided I take it exclusively in this sense, and I shall then say that a parallelogram has three angles, equal to two right angles. But if, leaving to this word its ordinary signification and idea, which is that of signifying a figure whose sides are parallel, I were to say that a parallelogram is a figure with three lines—as this would then be a definition of a thing—it would be very false, it being impossible for a figure of three lines to have its sides parallel.
It follows, in the second place, that the definitions of names cannot be contested, because they are arbitrary; for we cannot deny that a man has given to a sound the signification which he says he has given to it, neither that it has that signification only in the use which he makes of it, after we have been forewarned of it; but, as to the definitions of things, it is often necessary to contest them, since they may be false, as we have before shown.
It follows, in the third place, that every definition of a name, since it cannot be contested, may be taken as a principle, whereas the definitions of things cannot at all be taken as principles, and are truly propositions which may be denied by those who find any obscurity in them, and which, consequently, must be proved, as other propositions, and not taken for granted, at least when they are not evident of themselves as axioms.
Nevertheless, what we have just said—that the definition of a name may be taken for a principle—needs some explanation. For this is only true, because we ought not to dispute that the idea which has been designated may not be called by that name which has been given to it. But we ought not to infer anything further than this idea, or believe, because we have given it a name, that it signifies anything real. For example, I may define a chimera, by saying,—I call a chimera that which implies a contradiction; and yet it will not follow from this that a chimera is anything,—in the same way as if a philosopher says to me, -I call heaviness the inward principle which makes a stone fall without being impelled by anything. I will not contest this definition; on the contrary, I will receive it cheerfully, because it enables me to understand what he wishes to say; but I will deny that what he means by the word heaviness is anything real, since there is no such principle in stones.
I wished to explain this, since there are two great abuses which are current on this subject in philosophy. The first is, of confounding the definition of the thing with the definition of the name, and of attributing to the former that which belongs only to the latter; for, having made a hundred definitions, not of names, but of things, to suit their fancy, which are very false, and which do not explain at all the true nature of things, nor the ideas which we naturally have of them, they wish us then to consider these definitions as principles which none may contradict, and which if any one denies, as he may very easily, they pretend that he is not worth disputing with.
The second abuse is, that, scarcely ever employing the definition of names, in order to remove that obscurity which is in them, and fixing to them certain ideas clearly described, they leave them in their confusion, whence it happens that the greater part of their disputes are only disputes about words; and further, that they employ that which is clear and true in confused ideas, in order to establish that which is obscure and false, and which they would easily have perceived to be so, if they had defined the names.
Thus philosophers commonly believe that there is nothing in the world clearer than that fire is hot, and a stone heavy, and that it would be folly to deny this; and, in fact, they may persuade all men of this, so long as the names are undefined; but, on defining them, it will be easily found out, whether that which may be denied on this matter is clear, or obscure; for it will then be demanded of them, what they understand by the word hot, by the word heavy. If they answer, that by heat they understand only that which really produces the sensation heat in us, and by heavy, that which falls to the ground when nothing upholds it, they have good ground for saying, that it would be unreasonable to deny that fire is hot, and a stone is heavy; but, if they understand by heat, that which has in itself a quality resembling what we imagine when we feel heat, and by weight, that which has in itself a principle which makes it fall towards the centre, without being impelled by anything, it will be easy then to prove to them, that to deny that in this sense fire is hot, and a stone heavy, is not to deny a clear thing, but one that is very obscure, not to say very false, since it is very clear that the fire gives us a sensation of heat by the impression which it makes on our body, but it is not at all clear that the fire has anything in it which resembles what we feel when we approach the fire; and it is also very clear that a stone descends when we let it fall, but it is not at all clear that it descends of itself, without there being any thing to impel it downward.
We may see, thus, the great utility of the definition of names to enable us to understand exactly what is the point at issue,—to the end that we may not uselessly dispute about words which one understands in one sense, and another in another, as is so often the case in ordinary conversations.
But, besides this utility, there is still another, which is, that we often are not able to give a distinct idea of a thing, except by employing many words to describe it. Now, it would be wearisome, especially in books of science, to be always repeating this long series of words. Hence it is, that, having explained the thing by all these words, we attach to a single word the idea which we have conceived, which, in this way, takes the place of all the others. Thus, having comprehended that there are some numbers which may be divided into two equal parts, in order to avoid the constant repetition of these terms, we give a name to that property, saying, every number which is divisible into two equal parts we call an even number. This proves that, whenever we use the word which we have defined, we must mentally substitute the definition for the word defined, and have that definition so present, that, as soon as we mention it—e. g. an even number—we understand exactly that which is divisible into two equal parts, and that these two things are so inseparably joined in thought, that as soon as language expresses the one, the mind immediately attaches to it the other; for those who define terms with so much care as the geometers, do it only to abridge the language, which such frequent repetitions would render wearisome. Ne assidue circumloquendo moram faciamus—as St Augustine says; but they have no intention of abridging the ideas whereof they speak, since they suppose that the mind will supply a complete definition to the abbreviated terms which they may employ, to avoid the embarrassment which a multitude of words would create.