522 



SCIENCE 



[N. S. Vol. XXXI. No. 797 



I am using it. I am not employing it to 

 indicate "the sum of all knowledge" 

 (Paulsen), or as a synonym for tlie "sci- 

 ence of the absolute" (Hegel), but rather 

 as a branch of philosophy which is, in a 

 certain sense, supplementary to all the 

 individual sciences of phenomena. The 

 metaphysician here in mind is a gleaner 

 after physics and psychology, using these 

 two words in their wide meaning so as to 

 cover practically the whole of modern sci- 

 ence. He it is who orients the sciences 

 among themselves, criticizes their founda- 

 tions, their methods and even their con- 

 clusions, in so far as these conclusions de- 

 pend upon pure logic. He it is who rounds 

 out and corrects the individual sciences. 

 It will thus be seen that metaphysics, with 

 these limitations, does not differ widely 

 from the modern usage of the word phi- 

 losophy; for the metaphysics I have in 

 mind has been aptly characterized as "the 

 supreme science of order. "^ There are 

 those, and I myself am one of this class, 

 who prefer to use the word "epistemology" 

 to describe a metaphysics of this type. It 

 is certainly not the type of metaphysics 

 which allowed Kant to define matter in 

 terms of force.' And, in any event, I trust 

 we shall all agree that we are not getting 

 into what Maxwell called "the den of the 

 metaphysician, strewed with the remains 

 of former explorers, and abhorred by every 

 man of science." 



But we must be careful to remember that 

 the metaphysician which Maxwell here has 

 in mind is not an epistemologist, but a man 

 of the Hegelian type. Helmholtz* boasted 

 that he never lost an opportunity to impress 

 upon his students the principle that "a 



' Congress of Arts and Science, St. Louis, 1904, 

 Vol. 1, p. 236. 



' Hoeffding, " History of Modern Philosophy," 

 Vol. 2, p. 69. 



' Vortrage, " Das Denken in der Medicin," p. 34. 



metaphysical conclusion is either a false 

 conclusion or a concealed experimental 

 conclusion." How far removed the more 

 genuine metaphysics of to-day is from 

 that which held sway during the first half 

 of the nineteenth century and which exas- 

 perated men of the type of Maxwell and 

 Hehnholtz, may be indicated by the follow- 

 ing paragraph from Professor A. E. Tay- 

 lor,^ of Aberdeen, himself a distinguished 

 metaphysician. He says: 



Just because of the absence from metaphysics 

 itself of all empirical premises, it can be no busi- 

 ness of the metaphysician to determine what the 

 course of events will be or to prescribe to the 

 sciences what methods and hypotheses they shall 

 employ in the work of such determination. 

 Within these sciences any and every hypothesis 

 is suiEciently justified, whatever its nature, so 

 long as it enables us more efficiently than any 

 other to perform the actual task of calculation 

 and prediction. And it was owing to neglect of 

 this caution that the Naturphilosophie of the 

 early nineteenth century speedily fell into a dis- 

 repute fully merited by its ignorant presumption. 

 As regards the physical sciences, the metaphysi- 

 cian has indeed by this time probably learned his 

 lesson. 



It is hardly necessary to add that the 

 type of metaphysics here exposed is not 

 one to which physics owes anything what- 

 ever, and is not the one I have in mind dur- 

 ing these remarks. 



I. THE MECHANICAL POSTULATE 



The father of the present Duke of 

 Argyll rendered marked service to science 

 in pointing out how wide-spread is the use 

 of physical and natural law. But nowhere 

 in his notable volume, the "Reign of Law," 

 does he indicate what may be called the 

 most fundamental fact connected with the 

 discovery and employment of such law, 

 namely, that the very existence of laws 

 governing natural phenomena is a postu- 



° Congress of Arts and Science, St. Louis, 1904, 

 Vol. 1, p. 240. 



