EMANCIPA TION FROM SCIENTIFIC MA TERIA LISM. 421 



I do not fail to recognise that my undertaking places 

 me in opposition to the views of men who have done great 

 things for science, and to whom we all look up in wonder 

 and admiration. But do not charge me with presumption 

 if I oppose myself to such men in a matter of so great 

 importance. You do not call it presumption when the 

 sailor on duty at the mast-head turns the great ship from 

 her course by his cry of "Breakers ahead ! " albeit he is 

 but an insignificant member of her crew. His duty is to 

 announce what he sees, and did he fail to do this he would 

 prove untrue to this duty. It is in this sense a duty which 

 I am to-day discharging. Nevertheless, no one is bound 

 to alter his scientific course in answer to my cry of " Breakers 

 ahead ! " Every one is at liberty to test whether it is a 

 reality that stands before my eyes, or whether a mirage 

 deceives my vision. I believe however that the special 

 nature of my scientific duties gives me for the moment a 

 clearer insight into certain phenomena than may be had 

 from other points of view, and for this reason I could not 

 but reo-ard it as wrong:, were I for extraneous motives to 

 leave unsaid what I have seen. 



In order to find our way clearly through the infinite 

 variety of the world of phenomena, we always make use of 

 the same scientific method, namely, grouping together things 

 that are similar and in variety seeking the non-varying. In 

 this way our gradual mastery over the infinitely various 

 phenomena of the outer world is acquired and ever more 

 effective means of co-ordination are continually developed. 

 From the simple list we proceed to the system, from this 

 again to the lazv of nature^ and the most comprehensive 

 form of the latter condenses into a general conception. We 

 perceive that the phenomena of the actual world, limitless 

 as is their variety, form nevertheless only certain perfectly 

 definite and particular cases of the theoretically conceivable 

 possibilities. The significance of a Law of Nature consists 

 in the determination of the actual among the possible cases, 

 and the form to which each can be referred is the finding 

 of an invariant, that is to say, a quantity which remains 



