however, though real as far as it goes, is not necessarily absolute. For it may very well be that in the end the conditions upon which the possibility of inference depends are identical with or consequent upon the structure of reality. Even the fact that, under certain conditions, we can imagine an unreal state of things and then proceed to reason validly as to the results which would follow if this imaginary state were actual, may itself be a consequence of the actual nature of things. And, as a matter of fact, logicians have always found it impossible to inquire very deeply into the foundations and first principles of their own science without being led to face fundamental issues of Metaphysics. The distinction between the two studies must thus, according to the well-known simile of Bacon, be compared rather with a vein in a continuous block of marble than with an actual line of cleavage. Still it is at least so far effectual, that while many metaphysical questions have no direct bearing on Logic, the details of the theory of evidence are likewise best studied as an independent branch of knowledge. § 10. In recent years considerable prominence has been attained by a branch of study known as _Epistemology_, or the _Theory of Knowledge_. The _Theory of Knowledge_, like Logic, is primarily concerned with the question of the conditions upon which the validity of our thinking, as a body of knowledge about reality, depends. It differs from ordinary Logic in not inquiring into the details of the various processes of proof, but confining its attention to the most general and ultimate conditions under which valid thinking is possible, and discussing these general principles more thoroughly and systematically than common Logic usually does. Since the conditions under which truth is obtainable depend, in the last resort, on the character of that reality which knowledge apprehends, it is clear that the problems of the _Theory of Knowledge_, so far as they do not come under the scope of ordinary Logic (the theory of the estimation of evidence), are metaphysical in their nature. As actually treated by the writers who give this name to their discussions, the study appears to consist of a mixture of Metaphysics and Logic, the metaphysical element predominating. There is perhaps no serious harm in our giving, if we choose, the name _Epistemology_ or _Theory of Knowledge_ to our discussions of ultimate principles, but the older title Metaphysics seems on the whole preferable for two reasons. The discussion of the implications of knowledge is only one part of the metaphysician’s task. The truly real is not only the knowable, it is also that which, if we can obtain it, realises our aspirations and satisfies our emotions. Hence the theory of the real must deal with the ultimate implications of practical conduct and æsthetic feeling as well as those of knowledge. The Good and the Beautiful, no less than the True, are the objects of our study.