Note 74 — AN ESSAY ON THE PRINCIPLES OF HUMAN ACTION TO WHICH ARE ADDED SOME REMARKS ON THE SYSTEMS OF HARTLEY AND HELVETIUS

Similarity has been defined to be partial sameness. Curve lines have a general resemblance, or analogy to one another as such. Does this resemblance then consist in their being partially the same? This may be said where the difference arises from drawing out the same sort of curve to a greater extent because by adding to the shorter curve I can make it equal to the other. But I cannot by adding any other line to an oval convert it into a circle, because these two sorts of curves can never coincide even in their smallest conceivable parts. It should seem then that their similarity is not to be deduced from partial sameness, or their having some one thing exactly the same, common to them both. But they have the same general nature as curves. True: but in what does this abstract identity consist? Is it not the same with similarity? So that we return to the same point from which we set out. I confess no light appears to me to be thrown on the subject by saying that it is partial identity. The same sort of reasoning is applicable to the question whether all good is not to be resolved into one simple principle, or essence, or whether all that is really good or pleasurable in any sensation is not the same identical feeling, an infusion of the same level of good, and that all the rest is perfectly foreign to the nature of good and is merely the form or vehicle in which it is conveyed to the mind. I cannot however persuade myself that our sensations differ only as to more, or less; or that the pleasure derived from seeing a fine picture, or hearing a fine piece of music, that the gratification derived from doing a good action and that which accompanies the swallowing of an oyster are in reality and at bottom the same pleasure. The liquor tastes of the vessel through which it passes. It seems most reasonable to suppose that our feelings differ in their nature according to the nature of the objects by which they are excited, though not necessarily in the same proportion, as objects may excite very distinct ideas which have little or nothing to do with feeling. Why should there be only two sorts of feeling, pleasure and pain? I am convinced that any one who has reflected much on his own feelings must have found it impossible to refer them all to the same fixed invariable standard of good or evil, or by throwing away the mere husk and refuse without losing any thing essential to the feeling to arrive at some one simple principle, the same in all cases, and which determines by it’s quantity alone the precise degree of good or evil in any sensation. Some sensations are like others; this is all we know of the matter, and all that is necessary to form a class, or genus. The contrary method of reasoning appears to proceed on a supposition that things differing at all in kind must differ in toto, must be quite different from each other; so that a resemblance in kind must imply an absolute coincidence in part, or in as far as the things resemble one another.—See Usher on the Human Mind.