IV.] UNITY OF ALL KNOWLEDGE. 97 why confine the thoughts to the points on which they are conterminous, continuous and agreed, to the exclusion of those in which they differ, when it is on the points in which they differ that the great contributions to the real history of man are to be traced ? In any other sense than that in which I have attempted to limit it and have accepted it, the Unity of History is either the crotchet of a sciolist, or the dream of a universal philosopher. For just think how the field of view expands ; we can never know one thing perfectly unless we know everything ; true, but we can try to learn here and there a thing as perfectly as it can be learned, without knowing everything. In the same sense in which the careful study of ancient history is absolutely necessary to the careful study of modern history, the careful study of the latter is absolutely necessary to that of the former. If you read the second alone, where do you find your causes ? If you read the first alone, where do you find your consequences ? Just in the same way, it may be said, the external history of man cannot be read without an internal reading of his history ; no man can approach History without being a consummate moral philosopher ; yet is it so ? Then most of the great historians of the world have been great moral philosophers without knowing it. But how can a man pretend to understand the moral conformation of his fellows without knowing their physical conformation ? Then the moral philosopher must be an anatomist, and the anatomist a chemist, a botanist and geologist, and the geologist an astronomer; i.e. instead of borrowing, and being content to borrow from the kindred and allied sciences what is necessary for the consistent pursuit of our own study, we must know the principles of all, like the sophists of old, and we all know what that ends in, κακά! ηπιότατο πάντα. But my friend says, exaggeration is no argument, an answer which, by-the-by, may tell either Η