guiding stars, the only foundation, and the only aids to investigation. Experience supplies the facts, the empirical sciences, the provisional results of a systematic examination of these facts, and metaphysics starts from these results in order to carry them further and perfect them from a logical point of view" (pp. 210-11). There are no "fantastic analogies," Wundt's metaphysics has a scientific foundation. He likens him to Leibniz, "for to him as to the eailier philosopher no human knowledge is foreign, and he, like Leibniz, strives after a theory of the world which shall give full weight to the claims of both the formal and the real sciences. Wundt also arrives at a monado-logical system, although, to be sure, he substitutes units of will for units of perception, and has changed a scale of monads quietly resting side by side into an actual community and reciprocal determination of creative beings" (p. 221). But there is a serious difficulty with his idealism. Idealism uses the mind "as the key with which to unlock the world-secret." Wundt believes that the will expresses the being of the mind most exactly, and that the world is therefore a system of "will-units." Külpe feels that the will should not be regarded as more fundamental than any other element in the mind; the other elements cannot be reduced to the will, and they go just as much toward making up the mind as the will does. Therefore there is no reason for selecting the will as the key to the universe.
One might have preferred a different selection of the leading tendencies of thought and of the thinkers representing each tendency. To "avoid all controversy" on this subject Külpe "claims the right of personal opinion" (p. 8). But I think it may be said that given the tendencies and the thinkers and considering the limited space allowed to each thinker the exposition gives us the essentials. The criticism is always serious but clear and thoroughly sound. The translation is so good that one is not aware of reading the work in translation.
As the translators point out in the preface, Külpe has reserved the term 'Idealism' for objective or ontological idealism and excluded it from including epistemological idealism. It certainly makes for clearness to keep this term for one type of idealism, but it is very misleading to class epistemological idealism as a form of positivism. Epistemological idealism may approach positivism and it may be very far from it. Such thinkers as Lange, Cohen and Natorp do find the epistemological problem in experience as does Mach, but their method is about as far removed from that of Mach as can be imagined. On pp. 247-8 Külpe hints at this difference, but he does not carry it out.
M. Phillips Mason.
Harvard University.
