Here, again, one need only ask, How can such statements be reconciled with the great dogma, "which is indeed a necessary deduction from the theory of Natural Selection, namely, that none of the definite facts of organic nature, no special organ, no characteristic form or marking can exist, but which must now be, or once have been, _useful_"? Can it be said that the plumes of a bird of paradise present "no characteristic form," or the tail of a peacock "no characteristic marking"? Can it be held that all the "fantastic colours," which Darwin attributes to sexual selection, and all the "strange forms" in the vegetable world which present no conceivable reference to adaptation, are to be ascribed to "individual variability" without reference to utility, while at the same time it is held, "as a necessary deduction from the theory of Natural Selection," that _all_ specific characters must be "_useful_"? Or must we not conclude that we have here a contradiction as direct as a contradiction can well be[137]? [137] Since the above was written both Mr. Gulick and Professor Lloyd Morgan have independently noticed the contradiction. Nor is it any more possible to reconcile these contradictory statements by an indefinite extension of the term "correlation," than we found it to be in the cases previously quoted. It might indeed be logically possible, howsoever biologically absurd, to attribute the tail of a peacock--with all its elaboration of structure and pattern of colour, with all the drain that its large size and weight makes upon the vital resources of the bird, with all the increased danger to which it exposes the bird by rendering it more conspicuous, more easy of capture, &c.--to correlation with some useful character peculiar to peacocks. But to say that it is due to correlation with general "vitality," is merely to discharge the doctrine of correlation of any assignable meaning. Vitality, or "perfect adaptation to the conditions of existence," is obviously a prime condition to the occurrence of a peacock's tail, as it is to the occurrence of a peacock itself; but this is quite a different thing from saying that the specific characters which are presented by a peacock's tail, although useless in themselves, are correlated with some other and useful specific characters of the same bird--as we saw in a previous chapter with reference to secondary sexual characters in general. Therefore, when Mr. Wallace comes to the obvious question why it is that even in "allied species," which must be in equally "perfect adaptation to the conditions of existence," there are no such "wonderful superfluities of plumage," he falls back--as he previously fell back--on whatever unknown _causes_ it may have been which produced the peacock's tail, when the primary _condition_ to their operation has been furnished by "complete success in the battle for life."