1. With regard to the argument derived from classification: it is to be observed that any system of classification is in a certain sense artificial, and at all events is manifestly conventional. But, in order that no injustice may be done to this branch of the argument for evolution, I shall state it in its full force. The classifications which naturalists make of the different organized beings according to their resemblances and differences reveal the fact of unity amid multiformity. This fact it is said points to propinquity of descent, "which is the only known cause of the similarity of organic beings." It is the bond, hidden indeed by various degrees of modification, but nevertheless revealed to us by the classifications which display the resemblances. Again, we have, it is said, in the influence of various conditions of animated organisms, "the only known cause of divergence of structure." Classification reveals to us these divergences. We have, then, the bond of resemblances which indicate propinquity of descent, and the divergences of structure produced by varying conditions of life. Put the two together, and we have remarkable harmonies of likenesses obscured by unlikenesses; and to this state of facts it is claimed that no consistent interpretation can be given, without the hypothesis that the likenesses and the unlikenesses were produced by the evolution of organisms out of organisms by successive generation, through a great lapse of time. This argument contains no inconsiderable amount of assumption. While it may be true that some naturalists do not assign any cause for the similarity which obtains among organic beings excepting their descent from a common ancestral stock, it is not true that the similarity of structure is inconsistent with the hypothesis of another cause, namely, the adoption of a general plan of structure for a large class of organisms, and an intentional variation in those parts of structure which mark the divisions of that class into species that are very unlike. It is true that evolutionists treat with scorn the idea of a pattern of structure followed throughout a class of animals, but made by designed adaptations to coalesce with differences that mark the peculiarities which distinguish one organism of that class from all the others. Mr. Spencer, for example, observes that "to say that the Creator followed a pattern throughout, merely for the purpose of maintaining the pattern, is to assign a motive which, if avowed by a human being, we should call whimsical."