78 PRESENT-DAY RATIONALISM 



absolutely different in their essential nature. Force pro- 

 duces motion ; but it is as impossible that force can 

 determine motion as that two can be equal to three, or 

 that a thing can be and not be at the same time. The 

 necessity is as absolute in the one case as in the other." 



In order to show that s/iape or form of any thing in 

 Nature could not be the sole product of a force, Mr. 

 Croll takes a crystal for illustration. He observes : " All 

 that force does is simply to move or draw the molecules 

 and hold them together in the crystalline state. The 

 crystalline T^rw is therefore not due to the force, but to 

 that something, be it what it may, which is the cause 

 why the molecules have a [certain] shape, and why their 

 attraction is confined to the definite points on the sur- 

 faces of the molecules. 



" What, then, is the cause of determination ? This 

 is the all-important question, whether as regards life- 

 theories, theism or evolution." 



Mr. Croll is now led to his third proposition as 

 follows : — 



(3) " A/l the Energies and Forces of Nature are pro- 

 bably tJie same, and differ only i?i regard to their modes 

 of operation. 



" This proposition follows as a consequence from the 

 principle of the Conservation of Energy. 



" The only difference between chemical, electric, mag- 

 netic and heat energy is merely in the mode of operation. 

 The difference lies, therefore, not in the force or energy 

 itself, but in its determination, that is, not in the mere 

 exertion of force, but in the way or manner in which 

 force is exerted." 



Mr. Croll then proceeds to consider the bearing which 

 these propositions have on theories regarding the so-called 

 " Vital Force " and the Mystery of Life. 



