THE UNITY OF SCIENCE 21 



its entire development. Descartes, indeed, did not attempt to 

 bring the phenomena of consciousness within his unification; 

 between the nature and behavior of "thinking substance" and 

 those of "extended substance" he left an unresolved discon- 

 tinuity. But so far as the physical world is concerned, he had 

 no doubts about the possibility of a complete intellectual sim- 

 plification and synthesis which shall turn out to accord with 

 and to explain all the empirical facts. Nothing physical that 

 ever happens is anything more or less than the pushing or 

 knocking about of one piece of the contmuous matter that 

 fills all space by another piece. When you have formulated 

 the few and simple laws of this relative motion of masses and 

 have realized that the total quantity both of motion and of 

 matter is at all times constant, you have an all-comprehending 

 law, from which the exact time, place and manner of occur- 

 rence of every single phenomenon is theoretically deducible — 

 and would be actuallv deducible by man, if man had only 

 three items of additional information which have unfortu- 

 nately not been vouchsafed to him — viz., a statement of the 

 amount of that unchanging total of matter, and of that un- 

 changing total of motion, and a complete account of their dis- 

 tribution throughout the physical universe at the first mo- 

 ment, or at any other given moment, of that universe's exist- 

 ence. All sciences thus appear as at least ideally one science ; 

 all laws or descriptive generalizations as possible deductions 

 from one short system of universal and fundamental laws. 

 And these fundamental laws are laws of mechanism; that is, 

 they merely set forth uniformities in the relative motion of 

 portions of matter which differ from one another only quanti- 

 tatively and locally, which never undergo any augmentation of 

 their total quantity, and which, possessing only a few math- 

 ematically expressible characteristics, are therefore innocent 

 of the opulent but scientifically baffling manifoldness of the 

 world of objects as immediately perceived. 



But these early unifications of science were rather pious 

 aspirations than achieved results. In the existing state of 



