240 METAPHYSICS 



may, if we please, with Professor Royce, distinguish the two attitudes 

 toward fact as the attitude respectively of description and of appre- 

 ciation or evaluation. Now as regards the descriptive sciences, the 

 position to which, as I believe, metaphysicians are more and more 

 tending is that here metaphysics has, strictly speaking, no right at all 

 to interfere. Just because of the absence from metaphysics itself of all 

 empirical premises, it can be no business 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 w r ork 

 of such determination. Within these sciences any and every hypothe- 

 sis is sufficiently justified, whatever its nature, so long as it enables 

 us more efficiently than any other to perform the actual task of calcu- 

 lation and prediction. And it was owing to neglect of this caution 

 that the Natur philosophic of the early nineteenth century speedily fell 

 into a disrepute fully merited by its ignorant presumption. As regards 

 the physical sciences, the metaphysician has indeed by this time 

 probably learned his lesson. We are not likely to-day to repeat the 

 mistake of supposing that it is for us as metaphysicians to dictate 

 what shall be the physicist's or chemist's definition of matter or mass 

 or elementary substance or energy, or how he shall formulate the 

 laws of motion or of chemical composition. Here, at any rate, we can 

 see that the metaphysician's work is done when his analysis has made 

 it clear that we are dealing with no self-evident truths such as the 

 laws of number, but with inductive, and therefore problematic and 

 provisional results of empirical assumptions as to the course of facts, 

 assumptions made not because of their inherent necessity, but because 

 of their practical utility for the special task of calculation. It is only 

 when such empirical assumptions are treated as self-evident axioms, 

 in fact when mechanical science gives itself out as a mechanistic 

 philosophy, that the metaphysician obtains a right to speak, and then 

 only for the purpose of showing by analysis that the presence of the 

 empirical postulates which is characteristic of the natural sciences of 

 itself excludes their erection into a philosophy of first principles. 



What is important in this connection is that we should recognize 

 quite clearly that psychology stands in this respect on precisely the 

 same logical footing as physics or chemistry. It is tempting to sup- 

 pose that in psychology, at any rate, we are dealing throughout with 

 absolute certainties, realities which " consciousness " apprehends just 

 as they are without any of that artificial selection and construction 

 which, as we are beginning to see, is imposed upon the study of physi- 

 cal nature by the limitations of our purpose of submitting the course 

 of events to calculation and manipulation. And it is a natural conse- 

 quence of this point of view to infer that since psychology deals 

 directly with realities, it must be taken as the foundation of the meta- 

 physical constructions which aim at understanding the general char- 



