AS REGARDS PROTOPLASM, ETC. 69 



eclipses, etc., and yet the shadow (darkness) is the reverse of 

 light. 



This, then, is the assertion : In all cases of causality, the tie, 

 the copula, denied by Hume really exists ; the " step taken by the 

 mind" really is supported on a " process of the understanding;" 

 this tie, copula, step, process, has explicitly, or implicitly its 

 grounds and sufficient reason in Identity. 



One can conjecture much opposition here. Is the pain of a 

 burn identical with the flame that caused it, then 1 This, one 

 can hear the Revulsion bawl out ; to a man ! Causality as such, 

 however, ceases with the inorganic world. Assuch,it has no place 

 in will, reason ; and vitality itself has already set bounds to it 

 not but that a good stick may smash my skull and my wife's 

 pipkin on precisely the same principles. 



It is the motion, then, that is both the true cause and the true 

 effect in the case of the billiard balls. In the ordinary row of 

 such balls suspended for experiment by strings, the motion with 

 which the last leaps off is precisely the same motion with which 

 the first was allowed to impinge. It may seem a contradiction 

 and a difficulty here that both balls the first and the last 

 being allowed, at once, and similarly, to impinge on the rest, 

 the one motion seems merely to be counteracted and destroyed 

 by the other. Is the double motion, thus, then, only neutralised 

 arid lost ? No ; the motion counterbalanced in mass reappears 

 in molecule ; and we meet here the doctrine of the Conserva- 

 tion of Force or Energy. Not quite stable in its metaphysics 

 Eet, this doctrine is probably sound, so far, in its physics, 

 iglit and heat, however they may express themselves to 

 sentiency, or to a medium that dilates on molecular vibration, are, 

 in themselves, it seems, only motions, as magnetism, galvanism, 

 etc., in some unexplained way, may also be. In. that case, we 

 may conceive nothing in space but matter and motion. Nay, 

 in that case, may we not conceive nothing in space but motion 

 alone ? Matter itself shall be but counterbalanced motion as 

 it were implicit motion, which the flutter of a feather, in 

 changing the direction of opposing tendencies, may instantly 

 render explicit. A weight on a spring these are but counter- 

 vailing motions, and the slightest shift would enable them to 

 express themselves. The earth itself, then, may be conceived 

 not that I deny matter as but a congeries of belts of 

 countervailing motions ; and something of a rational basis 

 may be seen thus to be extended to those who feign matter 

 to be the expression of innumerable centres whence, what, 

 or how, one knows not ! of force. The fact of countervailing 

 motion must be allowed, however, to demonstrate as in 

 the spring and the weight the reality of motion without 

 its expression. One can see also the possible dispersion of any 



