It is easy to see, among the principles of Association, what particular principle it is, which is mainly concerned in Classification, and by which we are rendered capable of that mighty operation; on which, as its basis, the whole of our intellectual structure is reared. That principle is Resemblance. It seems to {271} be similarity or resemblance which, when we have applied a name to one individual, leads us to apply it to another, and another, till the whole forms an aggregate, connected together by the common relation of every part of the aggregate to one and the same name. Similarity, or Resemblance, we must regard as an Idea familiar and sufficiently understood for the illustration at present required. It will itself be strictly analysed, at a subsequent part of this Inquiry. So deeply was the sagacious mind of Plato, far more philosophical than that of any who succeeded him, during many ages, struck with the importance of Classification, that he seems to have regarded it as the sum of all philosophy; which he described, as being the faculty of seeing "the ONE in the MANY, and the MANY in the ONE;" a phrase which, when stripped from the subtleties of the sophists whom he exposed, and from the mystical visions of his successors, of which he never dreamed, is really a striking expression of what in classification is the matter of fact. His error lay, in misconceiving the ONE; which he took, not for the aggregate, but something pervading the aggregate.[79] [80] [Grote's footnote 79: The two chapters (VII. and VIII.) of Mr. James Mill's Analysis are highly instructive, and exhibit all his customary force and perspicuity. But in respect to Classification and Abstraction, I think that the ancient philosophers of the Sokratic school generally, are entitled to more credit than he allows them; and moreover that in respect to the difference of opinion between Plato and Aristotle, he has assigned an undue superiority to the former at the expense of the latter.