University of Virginia Library

How identical propositions are trifling.

I know there are some who, because identical propositions are self-evident, show a great concern for them, and think they do great service to philosophy by crying them up; as if in them was contained all knowledge, and the understanding were led into all truth by them only. I grant as forwardly as any one, that they are all true and self-evident. I grant further, that the foundation of all our knowledge lies in the faculty we have of perceiving the same idea to be the same, and of discerning it from those that are different; as I have shown in the foregoing chapter. But how that vindicates the making use of identical propositions, for the improvement of knowledge, from the imputation of trifling, I do not see. Let any one repeat, as often as he pleases, that "the will is the will," or lay what stress on it he thinks fit; of what use is this, and an infinite the like propositions, for the enlarging our knowledge? Let a man abound, as much as the plenty of words which he has will permit, in such propositions as these: "a law is a law," and "obligation is obligation"; "right is right," and "wrong is wrong":--will these and the like ever help him to an acquaintance with ethics, or instruct him or others in the knowledge of morality? Those who know not, nor perhaps ever will know, what is right and what is wrong, nor the measures of them, can with as much assurance make, and infallibly know, the truth of these and all such propositions, as he that is best instructed in morality can do. But what advance do such propositions give in the knowledge of anything necessary or useful for their conduct?

He would be thought to do little less than trifle, who, for the enlightening the understanding in any part of knowledge, should be busy with identical propositions and insist on such maxims as these: "substance is substance," and "body is body"; "a vacuum is a vacuum," and "a vortex is a vortex"; "a centaur is a centaur," and "a chimera is a chimera," etc. For these and all such are equally true, equally certain, and equally self-evident. But yet they cannot but be counted trifling, when made use of as principles of instruction, and stress laid on them as helps to knowledge; since they teach nothing but what every one who is capable of discourse knows without being told, viz., that the same term is the same term, and the same idea the same idea. And upon this account it was that I formerly did, and do still think, the offering and inculcating such propositions, in order to give the understanding any new light, or inlet into the knowledge of things, no better than trifling.

Instruction lies in something very different; and he that would enlarge his own or another's mind to truths he does not yet know, must find out intermediate ideas, and then lay them in such order one by another, that the understanding may see the agreement or disagreement of those in question. Propositions that do this are instructive; but they are far from such as affirm the same term of itself; which is no way to advance one's self or others in any sort of knowledge. It no more helps to that than it would help any one in his learning to read, to have such propositions as these inculcated to him--"An A is an A," and "a B is a B"; which a man may know as well as any schoolmaster, and yet never be able to read a word as long as he lives. Nor do these, or any such identical propositions help him one jot forwards in the skill of reading, let him make what use of them he can.

If those who blame my calling them trifling propositions had but read and been at the pains to understand what I have above writ in very plain English, they could not but have seen that by identical propositions I mean only such wherein the same term, importing the same idea, is affirmed of itself: which I take to be the proper signification of identical propositions; and concerning all such, I think I may continue safely to say, that to propose them as instructive is no better than trifling. For no one who has the use of reason can miss them, where it is necessary they should be taken notice of; nor doubt of their truth when he does take notice of them.

But if men will call propositions identical, wherein the same term is not affirmed of itself, whether they speak more properly than I, others must judge; this is certain, all that they say of propositions that are not identical in my sense, concerns not me nor what I have said; all that I have said relating to those propositions wherein the same term is affirmed of itself. And I would fain see an instance wherein any such can be made use of, to the advantage and improvement of any one's knowledge. Instances of other kinds, whatever use may be made of them, concern not me, as not being such as I call identical.