146 POPULAR SCIENCE MONTHLY. 



of prediction. This power comes only when we have such a store 

 of general principles to consult, and can with their help state with 

 confidence just what will happen under any given set of conditions. 



Judged by this stricter standard, many of our so-called sciences 

 are only now earning the name. Chemistry is an excellent case in 

 point. Tor many years it was purely inductive. Every new re- 

 action was very properly described as an experiment, for no one 

 knew precisely what would happen. It is still largely experimental. 

 But out of this accumulation of experimental data there are slowly 

 emerging a few general principles which give us the power of limited 

 prediction. 



It is the same with physics and the group of studies generally 

 classed as natural sciences. Some of them, such as mineralogy, are 

 hardly sciences as yet, since they allow small deduction. Similarly 

 with the group of studies that may be called the human sciences — 

 sociology and economics. So far as they are primary, they must first 

 be studied in their manifestations, and any general laws wrought out 

 from just such a mass of details. 



These remarks are limited to the primary sciences. The distinc- 

 tion between these and what may be called the secondary sciences is 

 of great practical importance. I conceive those to be primary which 

 are, so far as we know, self-founded, and must perforce work out 

 their own laws. The first stage of their development is necessarily 

 inductive, for they have nothing to build upon except direct and 

 immediate experience. And I conceive those sciences to be second- 

 ary which receive their laws at second hand, if we may so phrase it, 

 from some more basic science, and simply apply them to a special 

 class of conclusions. Such sciences are necessarily derivative in 

 origin, and must proceed deductively. The present trend of scien- 

 tific opinion is to recognize but one science, mechanics, as funda- 

 mental or primary, and to regard all other sciences as secondary. It 

 does this when it attempts to explain the phenomena of these sciences 

 by referring them to mechanical principles. "With the progress of 

 scientific generalization we may look forward to a time when there 

 will be but one theorem in the geometry of Nature, and the separate 

 sciences of to-day — biology, physics, chemistry, sociology, and the 

 rest — will assemble themselves under this theorem as a series of mani- 

 fest corollaries. 



And I may say that such a view, suggested with increasing em- 

 phasis by the experimental sciences, is also in harmony with the 

 deepest generalization of a more abstract philosophy, which sees in 

 the universe the operation of but one power. It is also interesting 

 from a metaphysical point of view to notice that of all the concrete 

 sciences, the one chosen as fundamental — mechanics — is just that 



