it has the same drawback as the notion that the oak exists preformed in the acorn. It seems to imply a "preformation" theory; and, as such, to be inconsistent with modern views of the nature either of growth or of evolution. The steam-plough has grown or evolved from the primitive digging-stick by a series of changes which though they have been changes have an unbroken continuity. But this continuity affords not the slightest ground for supposing that the idea of the steam-plough existed, preformed, in the mind of the man who first used a digging-stick. Neither, however, does the undoubted continuity throw the least doubt on the fact that the digging-stick has considerably changed in the process of its evolution. Different as a steam-plough is from a digging-stick, there is unbroken continuity between the two; and the unbroken continuity manifests itself in the changes by which the implement in its later stages has been evolved from the implement in its earlier stages. Enormous as the difference is, the similarity is none the less. So too, I suggest, enormous as is the difference between a stage of religion in which there is no reference to beings superior to man, and later stages of polytheism or monotheism, the process by which the later stages have followed on the earlier has been a process not only of change but of continuity—of change in continuity and of continuity in change—a process in which the very differences postulate similarity, and the similarity implies difference. The continuity of the digging-stick and the steam-plough implies all the stages of difference which at the same time separate and yet unite them.
For the illustration of my argument I may perhaps employ a statement made by our President. He says (following Mr. J. Burnet, Early Greek Philosophy, p. 24): "European geometry would seem to be the outcome of the art of the 'cord-fasteners,' who measured out the land in Egypt after each inundation of the Nile." Now, Euro-
