The Philosophy of Evolution. 55* 



be exterior to the organism by which its presence is mani- 

 fested ; for vital energy acting through an organism is a unit, 

 and cannot, even in thought, be separated into distinguishable 

 portions. Change in the direction of vital energy indicates- 

 that the original impulse has been modified in its action by 

 encountering another force, for nothing but force can change 

 the direction of force. It does not fall within the range of 

 this paper to determine the nature of this exterior force which 

 is thus distinguishable from that acting through the vital or- 

 ganization, and therefore capable of separate objective repre- 

 sentation. Metaphysically we may say that force is resolva-- 

 ble into will, but will being purely personal is incapable of 

 material representation, and thus cannot enter into the deter-- 

 minations of physical science, which does not seek to discover 

 the origin of force, but deals solely with its presence. 



As the logician must assume his premises, and. as a logi- 

 cian, cannot question their truth, so the physicist must assume 

 a force in operation, and, as a physicist, cannot examine its- 

 genesis. The physical or the metaphysical method of inquiry 

 is valid only so long as restricted to physical or metaphysical 

 processes : a' mixture of the two methods will give results satis- 

 factory neither to science nor to philosophy. As logic fur- 

 nishes no criterion by which to test the absolute truth of prop' 

 ositions, but deals wholly with conclusions drawn from given 

 premises, so science furnishes no data by which to determine 

 the absolute genesis of force, but restricts its enquiries to the 

 phenomena resulting from a force given. For the student of 

 physical science cause and effect is only the transference of a 

 given and determined force from one material form to another. 

 If this idea is to be traced further, it must be studied outside 

 the limits of physics. This study belongs to metaphysics. 



Now, if physical science does not deal with the origin of the 

 initial force, but assumes at the outset its presence, no more 

 does it fall within its province to examine into the origin of 

 the increments which give to physical forms that variety which 



