NECESSARY TRUTHS— EFFECTS OF EXPERIENCE. 671 



ideals, aud keep us uneasj and striving alwaj's to recast 

 the world of sense until its lines become more congruent 

 with theirs. Take for example the principle that ' nothing 

 can happen without a cause.' We have no definite idea of 

 what we mean by cause, or of what causality consists in. But 

 the principle expresses a demand for some deeper sort of 

 inward connection between phenomena than their merely 

 habitual time-sequence seems to us to be. The word 'cause ' 

 is, in short, an altar to an unknoAvn god ; an empty pedes- 

 tal still marking tlie place cf a hoped-for statue. Any 

 really inward belonging-together of the sequent terms, if 

 discovered, would be accepted as what the word cause was 

 meant to stand for. So we seek, and seek ; and in the 

 molecular systems we find a sort of inward belonging in 

 the notion of identity of matter with change of collocation. 

 Perhaps by still seeking we may find other sorts of inward 

 belonging, even between thennolecules and those ' secondary 

 qualities,' etc., which they produce upon our minds. 



It cannot be too often repeated that the triumphant 

 application of any one of our ideal systems of rational rela- 

 tions to the real world justifies our hope that other sys- 

 tems may be found also applicable. Metaphysics should 

 take heart from the examj)le of ph^'sics, simph- confessing 

 that hers is the longer task. Nature 7nay be remodelled, 

 nay, certainly will be remodelled, far beyond the point at 

 present reached. Just how far ? — is a question which only 

 the whole future history of Science and Philosophy can 

 answer.* Our task being Psj^chology, we cannot even 

 cross the threshold of that larger j^roblem. 



Besides the mental structure which results in such 



those ideal relations obtain. Thus, we can no longer call animal breeds by 

 the name of 'species '; cannot call generating a kind of 'giving,' or treat a 

 descendant as an ' effect ' of his ancestor. The ideal scheme of terms and 

 relations can remain, if you like ; but it must remain purely mental, and 

 without application to life, which 'gangs its aiu gait ' regardless of ideal 

 schemes. 3Iost of us, however, would prefer to doubt whether such abstract 

 axioms as that ' a thing cannot tend to its own destruction ' express ideal 

 relations of an important sort at all. 



* Compare A. Riehl: Der Phiiosophische Kriticismus, Bd. ii. Thl. i. 

 Abschn. i. Cap. m. § 6. 



