An Essay Concerning Humane Understanding, Volume I: Book II, Chapter XXVII.

Too Long; Didn't Read

1. Wherein Identity consists. ANOTHER occasion the mind often takes of comparing, is the very being of things, when, considering ANYTHING AS EXISTING AT ANY DETERMINED TIME AND PLACE, we compare it with ITSELF EXISTING AT ANOTHER TIME, and thereon form the ideas of IDENTITY and DIVERSITY. When we see anything to be in any place in any instant of time, we are sure (be it what it will) that it is that very thing, and not another which at that same time exists in another place, how like and undistinguishable soever it may be in all other respects: and in this consists IDENTITY, when the ideas it is attributed to vary not at all from what they were that moment wherein we consider their former existence, and to which we compare the present. For we never finding, nor conceiving it possible, that two things of the same kind should exist in the same place at the same time, we rightly conclude, that, whatever exists anywhere at any time, excludes all of the same kind, and is there itself alone. When therefore we demand whether anything be the SAME or no, it refers always to something that existed such a time in such a place, which it was certain, at that instant, was the same with itself, and no other. From whence it follows, that one thing cannot have two beginnings of existence, nor two things one beginning; it being impossible for two things of the same kind to be or exist in the same instant, in the very same place; or one and the same thing in different places. That, therefore, that had one beginning, is the same thing; and that which had a different beginning in time and place from that, is not the same, but diverse. That which has made the difficulty about this relation has been the little care and attention used in having precise notions of the things to which it is attributed. 2. Identity of Substances. We have the ideas but of three sorts of substances: 1. GOD. 2. FINITE INTELLIGENCES. 3. BODIES. First, GOD is without beginning, eternal, unalterable, and everywhere, and therefore concerning his identity there can be no doubt. Secondly, FINITE SPIRITS having had each its determinated time and place of beginning to exist, the relation to that time and place will always determine to each of them its identity, as long as it exists. Thirdly, The same will hold of every PARTICLE OF MATTER, to which no addition or subtraction of matter being made, it is the same. For, though these three sorts of substances, as we term them, do not exclude one another out of the same place, yet we cannot conceive but that they must necessarily each of them exclude any of the same kind out of the same place: or else the notions and names of identity and diversity would be in vain, and there could be no such distinctions of substances, or anything else one from another. For example: could two bodies be in the same place at the same time; then those two parcels of matter must be one and the same, take them great or little; nay, all bodies must be one and the same. For, by the same reason that two particles of matter may be in one place, all bodies may be in one place: which, when it can be supposed, takes away the distinction of identity and diversity of one and more, and renders it ridiculous. But it being a contradiction that two or more should be one, identity and diversity are relations and ways of comparing well founded, and of use to the understanding.