Now, it is to be borne in mind that while his rejection of miracles as violation of inviolable laws is entirely a priori—­for, discussion of such a matter is, of course, impossible for a rational thinker—­yet his rejection of supernatural intervention rests entirely on the scientific grounds of the necessity of looking for natural causes.  And he is quite logical in maintaining his position on these principles.  For, where it is either difficult or impossible to assign any rational cause for phenomena, or to discover their laws, he acquiesces reluctantly in the alternative of admitting some extra-natural interference which his essentially scientific method of treating the matter has logically forced on him, approving, for instance, of prayers for rain, on the express ground that the laws of meteorology had not yet been ascertained.  He would, of course, have been the first to welcome our modern discoveries in the matter.  The passage in question is in every way one of the most interesting in his whole work, not, of course, as signifying any inclination on his part to acquiesce in the supernatural, but because it shows how essentially logical and rational his method of argument was, and how candid and fair his mind.

Having now examined Polybius’s attitude towards the supernatural and the general ideas which guided his research, I will proceed to examine the method he pursued in his scientific investigation of the complex phenomena of life.  For, as I have said before in the course of this essay, what is important in all great writers is not so much the results they arrive at as the methods they pursue.  The increased knowledge of facts may alter any conclusion in history as in physical science, and the canons of speculative historical credibility must be acknowledged to appeal rather to that subjective attitude of mind which we call the historic sense than to any formulated objective rules.  But a scientific method is a gain for all time, and the true if not the only progress of historical criticism consists in the improvement of the instruments of research.

Now first, as regards his conception of history, I have already pointed out that it was to him essentially a search for causes, a problem to be solved, not a picture to be painted, a scientific investigation into laws and tendencies, not a mere romantic account of startling incident and wondrous adventure.  Thucydides, in the opening of his great work, had sounded the first note of the scientific conception of history.  ’The absence of romance in my pages,’ he says, ’will, I fear, detract somewhat from its value, but I have written my work not to be the exploit of a passing hour but as the possession of all time.’ {203} Polybius follows with words almost entirely similar.  If, he says, we banish from history the consideration of causes, methods and motives ([Greek]), and refuse to consider how far the result of anything is its rational consequent, what is left is a mere [Greek], not a [Greek], an oratorical essay which may give pleasure for the moment, but which is entirely without any scientific value for the explanation of the future.  Elsewhere he says that ’history robbed of the exposition of its causes and laws is a profitless thing, though it may allure a fool.’  And all through his history the same point is put forward and exemplified in every fashion.