certainly have to know theoretically that a few grains of antipyrine introduced into the organism have an influence on those brain centres which regulate the temperature of the human body. Yet if the chemist does not share the interest of the physician who wants to fight a fever, he would have hardly any reason for examining this particular relation, as it hardly throws light on the chemical constitution as such. In this way we might say in general that the relation of the world to us as acting individuals is in principle contained in the total system of the relations of our world of experience, but has a strictly accidental place there and can never be in itself a centre around which the scientific data are clustered, and science will hardly have an interest in giving any attention to its details. This relation of the world, the physical, the psychical, the historical, and the normative world, to our individual, practical purposes can, however, indeed become the centre of scientific interest, and it is evident that the whole inquiry receives thereupon a perfectly new direction which demands not only a completely new grouping of facts and relations, but also a very different shading in elaboration. As long as the purpose was to understand the world without relation to our individual aims, science had to gather endless details which are for us now quite indifferent, as they do not touch our aims; and in other respects science was satisfied with broad generalizations and abstractions where we have now to examine the most minute details. In short, the shifting of the centre of gravity creates perfectly new sciences which must be distinguished; and if we call them again theoretical and practical sciences, it is clear that this difference has then no longer anything to do with the philosophical problems from which we started.