of other human and animal minds, that furnishes the antithesis on which the distinction of Cosmology from Rational Psychology is founded. There is no confusion against which we shall need to be more on our guard than this fallacious identification of Mind or Spirit with the abstract subject of psychological states, and of the “environment” of the individual with Physical Nature. Of course, it is true that we necessarily interpret the inner life of other minds in terms of our own incommunicably individual experience, but it is equally true that our own direct experience of ourselves is throughout determined by interaction with other agents of the same type as ourselves. It is a pure delusion to suppose that we begin by finding ourselves in a world of mere physical things to some of which we afterwards come by an after-thought, based on “analogy,” to ascribe “consciousness” akin to our own. Hence, to avoid possible misunderstandings, it would be better to drop the traditional appellations “Cosmology” and “Rational Psychology,” and to call the divisions of applied Metaphysics, as Hegel does, the _Philosophy_ of _Nature_ and of _Spirit_ or _Mind_ respectively.[30] In recognising this sub-division of applied Metaphysics into two sections, dealing respectively with Physical Nature and with Mind or Spirit, we do not mean to suggest that there is an absolute disparity between these two classes of things. It is, of course, a matter for philosophical criticism itself to decide whether this difference may not in the end turn out to be merely apparent. This will clearly be the case if either minds can be shown, as the materialist holds, to be simply a peculiar class of highly complex physical things, or physical things to be, as the idealist contends, really minds of an unfamiliar and non-human type. It is sufficient for us that the difference, whether ultimate or not, is marked enough to give rise to distinct classes of problems, which have to be treated separately and on their own merits. We may feel convinced on general philosophical grounds that minds and physical things are ultimately existences of the same general type, whether we conceive that type after the fashion of the materialist or of the idealist, but this conviction does not in the least affect the fact that the special metaphysical problems suggested by our experience of physical things are largely different from those which are forced on us by our interest in the minds of our fellows. In the one connection we have, for instance, to discuss the questions connected with such categories as those of uniform spatial extension, uniform obedience to general law, the constitution of a whole which is an aggregate of parts; in the other, those connected with the meaning and value of ethical, artistic, and religious aspiration, the concept of moral freedom, the nature of personal identity. Even the categories which seem at first sight most readily applicable both to physical things and to minds, such