Page:Prolegomena to history- the relation of history to literature, philosophy, and science (IA prolegomentohist00teggiala).pdf/120

 to astronomical, geological, or biological theory, or as applicable to any evolution but that of man. It is introduced here merely to emphasize to students of human evolution, first, that the objections urged against Darwin's theory of natural selection may possibly be a result of his too ready acceptance of Lyell 's authority; and, second, that Darwin's procedure in taking "change" as the immediate subject of inquiry is not necessarily the only course open to them. Nor should this conclusion be taken as an argument against Hutton's principle that the Present is the key to the Past, although it does point to a modification of the procedure to be followed. The Present that lies before us is not even mainly "new," but consists for the greater part of things carried over from the Past. Hence, in attempting to discover "how things have come to be as they are," it is possible that the processes first to be investigated should be those manifested everywhere in repression and fixity, while in the second place would follow inquiry into the processes made visible in temporary "releases" from the restrictions of habit, custom, and accepted ideas.

"The system of nature is certainly in rule," but "we are not to limit nature with the uniformity of an equable progression. " The inquiry into present or "modern" processes of evolution was recognized by Hutton as an expedient in the earlier stages of investigation. Darwin saw clearly that the test of his theory lay in its applicability to the past. "He who rejects these views on the nature of the geological record," he remarked, "will rightly reject my whole theory." We may study the present in order to throw light upon the past, and we may begin by isolating what appear to be the existing processes, but, for verification, any evolutionary hypothesis must be shown to agree with what we know to have taken place in the course of time. The truth is that the discovery of a valid hypothesis necessitates an equal consideration of all the evidence. For any evolution, this is tripartite, consisting of (1) the existing series as arranged in order from lowest to highest;