METAPHYSICS AND THE OTHER SCIENCES 229 



From the acceptance of such a definition two important conse- 

 quences would follow. (1) The first is that metaphysics is at once 

 sharply discriminated from any study of the psychical process of 

 knowledge, if indeed, there can be any such study distinct from the 

 psychology of conception and belief, which is clearly not itself the 

 science we have in view. For the psychological laws of the formation 

 of concepts and beliefs are exemplified equally in the discovery and 

 propagation of truth and of error. And thus it is in vain to look to 

 them for any explanation of the difference between the two. Nor 

 does the otherwise promising extension of Darwinian conceptions 

 of the "struggle for existence" and the "survival of the fittest" 

 to the field of opinions and convictions appear to affect this con- 

 clusion. Such considerations may indeed assist us to understand 

 how true convictions in virtue of their " usefulness" gradually come 

 to be established and extended, but they require to presume the 

 truth of these convictions as an antecedent condition of their " use- 

 fulness" and consequent establishment. I should infer, then, that 

 it is a mistake in principle to .seek to replace ontology by a " theory 

 of knowledge," and should even be inclined to question the very 

 possibility of such a theory as distinct from metaphysics on the one 

 hand and empirical psychology on the other. (2) The second con- 

 sequence is of even greater importance. The inquiry into the gen- 

 eral character by which the contents of true assertions are discrim- 

 inated from the contents of false assertions must be carefully dis- 

 tinguished from any investigation into the truth or falsehood of 

 special assertions. To ask how in the end truth differs from falsehood 

 is to raise an entirely different problem from that created by asking 

 whether a given statement is to be regarded as true or false. The dis- 

 tinction becomes particularly important when we have to deal with 

 what Locke would call assertions of "real existence," i. e., assertions 

 as to the occurrence of particular events in the temporal order. All 

 such assertions depend, in part at least, upon the admission of what 

 we may style "empirical" evidence, the immediate unanalyzed 

 witness of simple apprehension to the occurrence of an alleged 

 matter of fact. Thus it would follow from our proposed conception 

 of metaphysics that metaphysics is in principle incapable either of 

 establishing or refuting any assertion as to the details of our immedi- 

 ate experience of empirical fact, though it may have important bear- 

 ings upon any theory of the general nature of true Being which we 

 may seek to found upon our alleged experiences. In a word, if our 

 conception be the correct one, the functions of a science of meta- 

 physics in respect of our knowledge of the temporal sequence of 

 events psychical and physical must be purely critical, never con- 

 structive, a point to which I shall presently have to recur. 



One more general reflection, and we may pass to the consideration 



