MATTER, MOTION, AND FORCE 



the chemist and physicist " had to deal with 

 quantities and weights which were apt, wholly 

 or in part, to be annihilated, there would be 

 introduced an incalculable element, fatal to all 

 positive conclusions." And since motions of 

 masses and molecules form a principal part of 

 the subject-matter of the three abstract-concrete 

 sciences, it is obvious that " if these motions 

 might either proceed from nothing or lapse into 

 nothing, there would be an end to scientific in- 

 terpretation of them ; " no science of chemis- 

 try, or of physics, molecular or molar, would be 

 possible. 



The evidence which has secured universal 

 acceptance for these twin theorems has been 

 chiefly inductive evidence. The ancients freely 

 admitted that matter might be created and de- 

 stroyed ; and until the time of Galileo it was 

 supposed that moving bodies had a natural 

 tendency to lose their motion by degrees until 

 they finally stopped. Falsifying many of the 

 complex conditions in the case, the ancients 

 verbally maintained the negations of the theo- 

 rems that matter is indestructible and motion 

 continuous ; although, if they had tried to real- 

 ize in thought their crude propositions, they 

 would have found it impossible. But gradually 

 it began to be perceived that in all cases where 

 matter disappears — as in the burning of wood 

 or the evaporation of water — the vanished 



*39 



