Now nothing can be more important than this passage in Aristotle’s Politics (v. 12.), which may be said to mark an era in the evolution of historical criticism.  For there is nothing on which Aristotle insists so strongly as that the generalisations from facts ought to be added to the data of the a priori method—­a principle which we know to be true not merely of deductive speculative politics but of physics also:  for are not the residual phenomena of chemists a valuable source of improvement in theory?

His own method is essentially historical though by no means empirical.  On the contrary, this far-seeing thinker, rightly styled il maestro di color che sanno, may be said to have apprehended clearly that the true method is neither exclusively empirical nor exclusively speculative, but rather a union of both in the process called Analysis or the Interpretation of Facts, which has been defined as the application to facts of such general conceptions as may fix the important characteristics of the phenomena, and present them permanently in their true relations.  He too was the first to point out, what even in our own day is incompletely appreciated, that nature, including the development of man, is not full of incoherent episodes like a bad tragedy, that inconsistency and anomaly are as impossible in the moral as they are in the physical world, and that where the superficial observer thinks he sees a revolution the philosophical critic discerns merely the gradual and rational evolution of the inevitable results of certain antecedents.

And while admitting the necessity of a psychological basis for the philosophy of history, he added to it the important truth that man, to be apprehended in his proper position in the universe as well as in his natural powers, must be studied from below in the hierarchical progression of higher function from the lower forms of life.  The important maxim, that to obtain a clear conception of anything we must ‘study it in its growth from the very beginning’ is formally set down in the opening of the Politics, where, indeed, we shall find the other characteristic features of the modern Evolutionary theory, such as the ‘Differentiation of Function’ and the ‘Survival of the Fittest’ explicitly set forth.

What a valuable step this was in the improvement of the method of historical criticism it is needless to point out.  By it, one may say, the true thread was given to guide one’s steps through the bewildering labyrinth of facts.  For history (to use terms with which Aristotle has made us familiar) may be looked at from two essentially different standpoints; either as a work of art whose [Greek] or final cause is external to it and imposed on it from without; or as an organism containing the law of its own development in itself, and working out its perfection merely by the fact of being what it is.  Now, if we adopt the former, which we may style the theological view, we shall be in continual danger of tripping into the pitfall of some a priori conclusion—­that bourne from which, it has been truly said, no traveller ever returns.