Passing from red to red, red, red, through a succession of distinguishable shades, is one train of pure sensation: passing from red to green, blue, tasting, smelling, hearing, touching, is another train of pure sensation; that these are not the same trains, but different trains, consists in their being felt to be so; they would not be different, but for the feeling: and that a feeling is different, and known to be so, are not two things, but one and the same thing. Having two such trains, I want marks to distinguish them. For this purpose, I invent the words “same,” “similar,” and their contraries; by means of which, my object is attained. I call the parts of a train, such as the first, “same,” or “similar;” those of a train like the last, “different,” “dissimilar.”
By these relative terms, we name the sensations in pairs. When we say, same, we mean that sensations 17 A, and B, are the same; different, that A, and B, are different; like and unlike, the same. By these words we have four pairs of relative terms.
| A. | B. |
| same | same |
| different | different |
| like | like |
| unlike | unlike. |
The feeling is perfectly analogous in the case of the ideas of those sensations; and the naming is the same. Thus the idea of red, green, and so on, and the ideas of the different shades of red are distinguished from one another by the ideas themselves. To have ideas different and ideas distinguished, are synonymous expressions; different and distinguished, meaning exactly the same thing.
The sensations above mentioned, and their ideas, have the same absolute names: thus, red is at once the name of the sensation, and the name of the idea; green, at once the name of the sensation and the idea; sweet, at once the name of the sensation and the idea. The relative terms, it is obvious, have the same extent of application. Same, different, like, and unlike, are names of pairs of ideas, as well as pairs of sensations.
It seems, therefore, to be made clear, that, in applying to the simple sensations and ideas their absolute names, which are names of classes, as red, green, sweet, bitter; and also applying to them names which denote them in pairs, as such and such; there is nothing whatsoever but having the sensations, having the ideas, and making marks for them.[6]
[6] The author commences his survey of Relations with the most universal of them all. Likeness and Unlikeness; and he examines these as subsisting between simple sensations or ideas; for whatever be the true theory of likeness or unlikeness as between the simple elements, the same, in essentials, will serve for the likenesses or unlikenesses of the wholes compounded of them.
Examining, then, what constitutes likeness between two sensations (meaning two exactly similar sensations experienced at different times); he says, that to feel the two sensations to be alike, is one and the same thing with having the two sensations. Their being alike is nothing but their being felt to be alike; their being unlike is nothing but their being felt to be unlike. The feeling of unlikeness is merely that feeling of change, in passing from the one to the other, which makes them two, and without which we should not be conscious of them at all. The feeling of likeness, is the being reminded of the former sensation by the present, that is, having the idea of the former sensation called up by the present, and distinguishing them as sensation and idea.
It does not seem to me that this mode of describing the matter explains anything, or leaves the likenesses and unlikenesses of our simple feelings less an ultimate fact than they were before. All it amounts to is, that likeness and unlikeness are themselves only a matter of feeling: and that when we have two feelings, the feeling of their likeness or unlikeness is inextricably interwoven with the fact of having the feelings. One of the conditions, under which we have feelings, is that they are like and unlike: and in the case of simple feelings, we cannot separate the likeness or unlikeness from the feelings themselves. It is by no means certain, however, that when we have two feelings in immediate succession, the feeling of their likeness is not a third feeling which follows instead of being involved in the two. This question is expressly left open by Mr. Herbert Spencer, in his “Principles of Psychology;” and I am not aware that any philosopher has conclusively resolved it. We do not get rid of any difficulty by calling the feeling of likeness the same thing with the two feelings that are alike: we have equally to postulate likeness and unlikeness as primitive facts—as an inherent distinction among our sensations; and whichever form of phraseology we employ makes no difference in the ulterior developments of psychology. It is of no practical consequence whether we say that a phenomenon is resolved into sensations and ideas, or into sensations, ideas, and their resemblances, since under the one expression as under the other the resemblance must be recognised as an indispensable element in the compound.
When we pass from resemblance between simple sensations and ideas, to resemblance between complex wholes, the process, though not essentially different, is more complicated, for it involves a comparison of part with part, element with element, and therefore a previous discrimination of the elements. When we judge that an external object, compounded of a number of attributes, is like another external object; since they are not, usually, alike in all their attributes, we have to take the two objects into simultaneous consideration in respect to each of their various attributes one after another: their colour, to observe whether that is similar; their size, whether that is similar; their figure, their weight, and so on. It comes at last to a perception of likeness or unlikeness between simple sensations: but we reduce it to this by attending separately to one of the simple sensations forming the one cluster, and to one of those forming the other cluster, and if possible adjusting our organs of sense so as to have these two sensations in immediate juxtaposition: as when we put two objects, of which we wish to compare the colour, side by side, so that our sense of sight may pass directly from one of the two sensations of colour to the other. This act of attention directed successively to single attributes, blunts our feeling of the other attributes of the objects, and enables us to feel the likeness of the single sensations almost as vividly as if we had nothing but these in our mind. Having felt this likeness, we say that the sensations are like, and that the two objects are like in respect of those sensations: and continuing the process we pronounce them to be either like or unlike in each of the other sensations which we receive from them.—Ed.