But a still more serious objection to the evolutionary interpretation of homology and preadaptation arises from its intrinsic _incoherency_. Evolution, as previously stated, is assumed to be the resultant of a twofold process, namely, _inheritance_ and _variation_. The first is a conservative and similifying process, which transmits. The second is a progressive and diversifying process, which diverts. To the former process are due the uniformities of homology, to the latter the deviations of adaptation. Upon the admission of evolutionists themselves, however, neither of these processes behaves in a manner consistent with its general nature, and both of them are flagrantly unfaithful to the principal rôles assigned to them. Nowadays the hereditary process transmits _adaptational_, as well as _homologous_, characters. If, then, adaptational characters are more recent than homologous characters, there must have been a time when inheritance ceased to _similify_ and become a _diversifying_ process by transmitting what it did not receive from the previous generation. There were times when, not content with simply reiterating the past, it began to divert former tendencies into novel channels. In other words, inheritance becomes dualized into a paradoxical process, which both perpetuates the old and appropriates the new. The same inconsistency is manifest in the process of variation, which capriciously produces _convergent_, no less than _divergent_, adaptations. In two fundamentally identical structures, like the wing of a bird and the foreleg of a cat, variation is said to have produced diverse adaptations. In two fundamentally diverse structures, like the head of an octopus and the head of a frog, variation is said to have produced an identical adaptation, namely, the vertebrate type of eye. It appears, therefore, that the essentially diversifying process of variation can become, on occasion, a simplifying process, which, instead of solving environmental problems in an original manner, prefers to employ uniform and standardized solutions, and to cling to its old stereotyped methods. Inheritance similifies and diversifies, variation converges and diverges. It is futile to attempt to reduce either of these protean processes to a condition that even approximates consistency. The evolutionist blows hot and cold with the same breath. Verily, his god is Proteus, or the double-headed Janus!