THREE:The last mentioned principle gives one more illustration of the distinction between Aristotles system and that of the evolutionist, properly so called. The continuity recognised329 by the former only obtains among a number of coexisting types; it is a purely logical or ideal arrangement, facilitating the acquisition and retention of knowledge, but adding nothing to its real content. The continuity of the latter implies a causal connexion between successive types evolved from each other by the action of mechanical forces. Moreover, our modern theory, while accounting for whatever is true in Aristotles conception, serves, at the same time, to correct its exaggeration. The totality of existing species only imperfectly fill up the interval between the highest human life and the inorganic matter from which we assume it to be derived, because they are collaterally, and not lineally, related. Probably no one of them corresponds to any less developed stage of another, although some have preserved, with more constancy than others, the features of a common parent. In diverging from a single stock (if we accept the monogenetic hypothesis,) they have become separated by considerable spaces, which the innumerable multitude of extinct species alone could fill up.We have seen how Plato came to look on mathematics as217 an introduction to absolute knowledge. He now discovered a parallel method of approach towards perfect wisdom in an order of experience which to most persons might seem as far as possible removed from exact sciencein those passionate feelings which were excited in the Greek imagination by the spectacle of youthful beauty, without distinction of sex. There was, at least among the Athenians, a strong intellectual element in the attachments arising out of such feelings; and the strange anomaly might often be seen of a man devoting himself to the education of a youth whom he was, in other respects, doing his utmost to corrupt. Again, the beauty by which a Greek felt most fascinated came nearer to a visible embodiment of mind than any that has ever been known, and as such could be associated with the purest philosophical aspirations. And, finally, the passion of love in its normal manifestations is an essentially generic instinct, being that which carries an individual most entirely out of himself, making him instrumental to the preservation of the race in forms of ever-increasing comeliness and vigour; so that, given a wise training and a wide experience, the maintenance of a noble breed may safely be entrusted to its infallible selection.134 All these points of view have been developed by Plato with such copiousness of illustration and splendour of language that his name is still associated in popular fancy with an ideal of exalted and purified desire.
