Essay on Motion and Force. 



261 



indestructible in its nature, convertible into various forms 

 and only acting upon the concurrence of certain conditions. 



It seems to me that in speaking of these motions, the 

 application to them of the general term force, becomes, in 

 the present state of science, a positive impediment to 

 advancement. It is the domain of physics to seek to 

 ascertain the conditions under which matter moves, or in 

 other words undergoes change. All that can be predicated 

 of matter is, that it moves. Motion is doubtless an insep- 

 arable and probably an essential attribute of matter. To 

 say that it is moved, except by moving matter is, I think, to 

 assert that which is not susceptible of proof ; besides, when 

 we attempt to step beyond matter we enter the realm of 

 metaphysics, and to attempt to answer the question, Why 

 does matter move ? would be to plunge into the depths of 

 transcendental philosophy beyond the limit of human 

 thought, I therefore venture to assert that it is as foreign to 

 natural science, to attempt to discover why matter moves, 

 as to discover wiry matter is. That matter exists and 

 moves is, I think, the extreme limit to which the 

 mind of man can reach. In the light of the doctrine that 

 all the so called forces are motions of matter, there is no 

 other force than moving ?natter, and the term force as im- 

 plying something occult, should be discarded altogether. 

 Grove defines force as "that which produces or resists 

 motion, and also that active principle inseparable from 

 matter which is supposed to induce its various changes 

 He admits that the term is valueless except as a conven- 

 ience to expression, that we know nothing of the " modus 

 agendi of matter," and that the term force does not help 

 us to understand it. It seems to me that the word cause 

 is a much better term, and that the proposition that the cause 

 of all motion or change of matter, is an antecedent change or 

 changes of other matter is incontrovertible. Conditions only 

 are causes. As all matter moves incessantly, the only 

 change which it can possibly undergo, is a change of 

 motion, it never can reach a state of absolute rest. This 



[Trans, v.] 34 



