What is metaphysics? There is real danger of taking the meaning of this term too much for granted, and of leaning too heavily upon an undefined word in the very act of dismissing metaphysics as word jugglery. Metaphysics is not, as I conceive it, the study of the wholly transcendent or supersensible. It may sometimes have been so conceived, and this is, indeed, one reason why some of its alleged results are so unsatisfactory—or, as positivists would say, meaningless. Such a meaningless “metaphysical” idea is the mediaeval doctrine of God as a power acting upon the world but not reacted upon by it, as purposive but non-temporal, loving but “impassive,” etc. Such is the windowless monad of Leibniz, connected with other monads only by pre-established harmony. Such is the Aristotelian idea of substance as that in which other things inhere but which itself is in nothing (apparently not even in the world or nature). The history of metaphysics is, indeed, strewn with failures to achieve meaning. But does this mean that metaphysics has scored no successes? Surely we must remember that human success is invariably of the fumble-and-correction type. Ideas such as those mentioned may be meaningless as they stand, and yet have potential meaning in that some modification of them might render them significant conceptions. We must also remember that mankind now possesses new instruments of logical analysis, and that these instruments may prove useful in metaphysics—not, as logical positivism holds, with the result of banishing all metaphysical ideas, but of correcting their erroneous aspects.