THE METAPHYSICS OF SCIENCE. 371 



ence is liable to fail in its application to new phenom- 

 ena. The inference, therefore, can never be unreservedly 

 accepted except when the facts sustain quantitative and 

 therefore mathematical relations to each other. But 

 however qualified the inference, the metaphysical princi- 

 ple on which it proceeds is never accepted with reserve. 

 Uniformity of causation is felt to be absolute. The com- 

 mon process of inductive conclusion, which is the staple 

 method of science in the evolution of doctrine, requires, 

 consequently, an underlying metaphysical principle to 

 give it any semblance of validity. 



To avoid misconception it may be desirable to state 

 that the phrase "uniformity of nature" as here employed, 

 does not signify simply a continuous recurrence of iden- 

 tical cycles of phenomena, like those of a day, or the 

 orbital revolution of a planet, since such uniformity is 

 merely a generalization from observation, and must be 

 conceived capable of interruption. When this uniformity, 

 however, shall have been interrupted, it will be a result 

 proceeding from a higher principle of uniformity, which 

 requires that different effects under changed conditions 

 shall proceed from the same causal activity. 



So, it may be added, the uncertainty which, in any 

 case, or in all cases, hangs over a conclusion from in- 

 ductive data, arises not from any possible distrust of the 

 principle of uniformity of causation but from the possi- 

 bility that our imperfect judgment has admitted into the 

 comparison facts belonging to different categories of causa- 

 tion, and therefore connected only by superficial or casual 

 instead of fundamental relationships. Here lurks the falli- 

 bility of inductive conclusions; and here arises the demand 

 for profounder perceptions than finite minds possess, 



