It may be that the exceptional efficiency of a given edge-tool, _e.g._, will be accounted for on animistic or quasi-personal grounds,--grounds of magical efficacy; but it is the exceptional behavior of such a tool that calls for explanation on the higher ground of animistic potency, not its work-day performance of common work. So also if an edge-tool should fail to do what is expected of it as a matter of course, its failure may require an explanation in other terms than matter-of-fact. But all that only serves to bring into evidence the fact that a scheme of generalisations in terms of matter-of-fact is securely held and is made use of as a sufficient and ultimate explanation of the more familiar phenomena of experience. These commonplace matter-of-fact generalisations are not questioned and do not clash with the higher scheme of things. All this may seem like taking pains about trivialities. But the data with which any scientific inquiry has to do are trivialities in some other bearing than that one in which they are of account. In all succeeding phases of culture, developmentally subsequent to the primitive phase supposed above, there is found a similar or analogous division of knowledge between a higher range of theoretical explanations of phenomena, an ornate scheme of things, on the one hand, and such an obscure range of matter-of-fact generalisations as is here spoken of, on the other hand. And the evolution of the scientific point of view is a matter of the shifting fortunes which have in the course of cultural growth overtaken the one and the other of these two divergent methods of apprehending and systematising the facts of experience. The historians of human culture have, no doubt justly, commonly dealt with the mutations that have occurred on the higher levels of intellectual enterprise, in the more ambitious, more picturesque, and less secure of these two contrasted ranges of theoretical knowledge; while the lower range of generalisations, which has to do with work-day experience, has in great part been passed over with scant ceremony as lying outside the current of ideas, and as belonging rather among the things which engage the attention than among the modes, expedients and creations of this attention itself. There is good reason for this relative neglect of the work-day matters of fact. It is on the higher levels of speculative generalisation that the impressive mutations in the development of thought have taken place, and that the shifting of points of view and the clashing of convictions have drawn men into controversy and analysis of their ideas and have given rise to schools of thought. The matter-of-fact generalisations have met with relatively few adventures and have afforded little scope for intellectual initiative and profoundly picturesque speculation. On the higher levels speculation is freer, the creative spirit has some scope, because its excursions are not so immediately and harshly checked by material facts.