PART I.
THE KINDS OF SAMENESS.
And some require everything accurately stated; whereas, this accuracy annoys others, either because of their inability to follow a train of reasoning through, or because of its hair-splitting character; for accuracy does involve some hair-splitting.
Aristotle, Metaph. Book I, The Less, c. 3.
Section 1. There are few words the ambiguity of which has led to more confusion and profitless dispute than that of the word same. Men constantly use this word as though it had but one meaning, and that meaning were always clear, whereas it really gives expression to a number of widely different experiences, some of which are quite difficult of analysis. It is highly desirable that these experiences should not be confounded with each other, but kept clearly separate, as the consequences of such misconception are very far-reaching. How far-reaching, I shall in the pages to follow try to indicate.
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.
Now, without being a philosopher at all, and without conscious reference to anything beyond what he has experienced or can experience, he affirms that he has on two successive days seen the same tree. I ask, just what is the significance of the word same as used in this connection? What peculiar experience has it been employed to mark? What is perceived on the one occasion is not the same as what is perceived on the other in the sense of the word first given (by "perceived" I mean existing in consciousness as a complex of mental elements. With the supposed external correlates of our percepts I am not now concerned). And it is equally clear that two such percepts need not be the same in the second sense of the word, for they may be quite unlike. In this case they are unlike, so far at least as what is actually in sensation is concerned.