Let us try and express the consecutive steps of this case of reproduction. The thing now present to the mind has certain { 122} peculiarities in common with one or more things formerly present; as when, in a portrait, the outline and colouring resembles a subject original. These sensible effects make alive the previous recurrence of them, or put us in the cerebral and mental attitude formerly experienced by the corresponding effects of the resembling object. We are aware, by the liveliness of our impression, that we have gone in upon an old track; we have the peculiar consciousness called the consciousness of Identity or Agreement. This is one step, but not the whole. In order that the complete restoration may be effected, the features of community must be in such firm contiguous alliance with the features of difference--the _special_ part of the previous subject that the one shall reinstate the idea of the other. The points common to a present portrait and a past original must be so strongly coherent with the remaining features of the original, that the one cannot be awakened without the other following. Here, then, in the very heart of Similarity, is an indispensable bond of Contiguity; showing that it is not possible for either process to be accomplished in separation from the other. The mutual coherence of parts, now described as essential to reproduction, may be too weak for the purpose, and the recovering stroke of similarity will in that case fail.
It might, therefore, be supposed that Similarity is, after all, but a mode of Contiguity, namely, the contiguity or association of the different features or parts of a complex whole. The inference is too hasty. Because contiguity is a part of the fact of the restoration of similars, it is not the entire fact. There is a distinct and characteristic step preceding the play of this mutual coherence of the parts of the thing to be recovered. The striking into the former track of the agreeing part of the new and the old, is a mental movement by itself, which the other follows, but does not do away with. The effect above described, as the consciousness of agreement or identity, the flash of a felt similarity, is real and distinct. We are conscious of it by itself; there are occasions when we have it without the other, that is to say, without the full re-instatement of the former { 123} object in its entireness. We often aware of an identity without being able to say what is the thing identified; as when a portrait gives us the impression that we have seen the original, without enabling us to say who the original is. We have been affected by the stroke of identity or similarity; but the restoration fails from the feebleness of the contiguous adherence of the parts of the object identified. There is thus a genuine effect of the nature of pure similarity, or resemblance, and a mode of consciousness accompanying that effect; but there is not the full energy of reproduction without a concurring bond of pure contiguity. A portrait may fail to give us the consciousness of having ever seen the original. On the supposition that we have seen the original, this would be a failure of pure similarity.