LAW OF CAUSATION. 



231 



the air and the materials, which is 

 a force. To grind com, there must 

 be a certain collocation of the parts 

 composing a mill, relatively to one 

 another and to the com ; but there 

 must also be the gravitation of water, 

 or the motion of wind, to supply a 

 force. But as the force in these cases 

 was regarded as a property of the 

 objects in which it is embodied, it 

 seemed tautology to say that there 

 must be the collocation and the force. 

 As the collocation must be a colloca- 

 tion of objects possessing the force- 

 giving property, the collocation, so 

 understood, included the force. 



How, then, shall we have to express 

 these facts, if the theory be finally 

 substantiated that all Force is redu- 

 cible to a previous Motion ? We shall 

 have to say that one of the conditions 

 of every phenomenon is an antecedent 

 Motion. But it will have to be ex- 

 plained that this needs not be actual 

 motion. The coal which supplies the 

 force exerted in combustion is not 

 shown to have been exerting that force 

 in the form of molecular motion in the 

 pit ; it was not even exerting pressure. 

 The stone on the eminence is exerting 

 a pressure, but only equivalent to its 

 weight, not to the additional momen- 

 tum it would acquire by falling. The 

 antecedent, therefore, is not a force in 

 action ; and we can still only call it 

 a property of the objects, by which 

 they would exert a force on the occur- 

 rence of a fresh collocation. The col- 

 location, therefore, still includes the 

 force. The force said to be stored up, 

 is simply a particular property which 

 the object has acquired. The cause 

 we are in search of is a collocation 

 of objects possessing that particular 

 property. When indeed we inquire 

 further into the cause from which they 

 derive that property, the new concep- 

 tion introduced by the Conservation 

 theory comes in : the property is itself 

 an effect, and its cause, according to 

 the theory, is a former motion of 

 exactly equivalent amount, which has 

 been impressed on the particles of the 

 body, perhaps at some very distant 



period. But the casfe is simply one 

 of those we have already considered, 

 in which the efficacy of a cause con- 

 sists in its investing an object with a 

 property. The force said to be laid 

 up, and merely potential, is no more 

 a really existing thing than any other 

 properties of objects are really exist- 

 ing things. The expression is a mere 

 artifice of language, convenient for 

 describing the phenomena : it is un- 

 necessary to suppose that anything 

 has been in continuous existence ex- 

 cept an abstract potentiality. A force 

 suspended in its operation, neither 

 manifesting itself by motion nor by 

 pressure, is not an existing fact, but 

 a name for our conviction that in ap- 

 propriate circumstances a fact would 

 take place. We know that a pound 

 weight, were it to fall from the earth 

 into the sun, would acquire in falling 

 a momentum equal to millions of 

 pounds ; but we do not credit the 

 pound weight with more of actually 

 existing force than is equal to the 

 pressure it is now exerting on the 

 earth, and that is exactly a pound. 

 We might as well say that a force of 

 millions of pounds exists in a pound, 

 as that the force which will manifest 

 itself when the coal is burnt is a real 

 thing existing in the coal. What is 

 fixed in the coal is only a certain pro- 

 perty : it has become fit to be the ante- 

 cedent of an effect called combustion, 

 which partly consists in giving out, 

 under certain conditions, a given de- 

 finite quantity of heat. 



We thus see that no new general 

 conception of Causation is introduced 

 by the Conservation theory. The in- 

 destructibility of Force no more inter- 

 feres with the theory of Causation 

 than the indestructibility of Matter, 

 meaning by matter the element of 

 resistance in the sensible world. It 

 only enables us to understand better 

 than before the nature and laws of 

 some of the sequences. 



This better understanding, how- 

 ever, enables us, with Mr. Bain, to 

 admit, as one of the tests for distin- 

 guishing causation from mere con- 



