It is my purpose to point out the differences in connotation of the several senses of this highly ambiguous word, to show the element which they have in common, and to trace some of the difficulties and absurdities which have sprung from using the word loosely and without proper discrimination. I shall have to plead guilty to something very like hair-splitting, but I may put forward in excuse the undeniable fact that "accuracy does involve some hair-splitting." If anyone prefers the self-contradictions and preposterous conclusions to which loose and unanalytic thought has so often led the unwary, he is welcome to them. I shall hold a few of these up to inspection after a while. For my part, I prefer a little quibbling at the outset of a discussion to a systematic incoherence all through it, with the chances of finding myself in a _cul-de-sac_ at the end. Whether I am successful in dissipating to some degree the fog which has hung about samenesses and obliterated important distinctions, each one must judge for himself.
The kinds of sameness I find to be as follows:
SEC. 2. I. We speak of any sensation, feeling, or idea, or complex of sensations, feelings, or ideas, as being the same with itself at any one instant. The pain in my finger is what it is at this moment. The finger itself (the immediate object of knowledge, a complex from sense and imagination) is, at each moment, what it is. It is to this sense of the word that the logical laws of Identity and Contradiction have ultimate reference.
SEC. 3. II. A sensation, feeling, or idea, or complex of sensations, feelings, or ideas, considered in itself and without reference to the world of material things, is called the same with one previously existent when the two are alike. I say, for example, that I feel to-day the same pain I felt yesterday, or that I have dreamt the same dream three times. This is evidently not sameness of the kind first mentioned.
SEC. 4. III. We speak of seeing the same material thing at different times. Suppose a man passing along a country road to look across a field at a distant tree. What he actually sees is a small bluish patch of color, which, interpreting in terms furnished by his previous experience, he supplements with material drawn from memory and imagination. On the following day he looks at the tree again from a nearer point and sees a larger green patch of color with distinct differences of shading and with a clear outline. This he interprets in a similar manner.