36 The Mechanistic Conception of Life 



the mechanism for memory is developed but sUghtly or not at 

 all. It seemed to me that some day it must become possible 

 to discover the physico-chemical laws underlying the apparently 

 random movements of such animals ; and that the word "animal 

 will" was only the expression of our ignorance of the forces 

 which prescribe to animals the direction of their apparently 

 spontaneous movements just as unequivocally as gravity 

 prescribes the movements of the planets. For if a savage 

 could directly observe the movements of the planets and should 

 begin to think about them, he would probably come to the con- 

 clusion that a "will action" guides the movements of the planets 

 just as a chance observer is today inclined to assume that "will" 

 causes animals to move in a given direction. 



The scientific solution of the problem of will seemed then 

 to consist in finding the forces which determine the movements 

 of animals, and in discovering the laws according to which 

 these forces act. Experimentally, the solution of the problem 

 of will must take the form of forcing, by external agencies, any 

 number of individuals of a given kind of animals to move in 

 a definite direction by means of their locomotor apparatus. 

 Only if we succeed in this have we the right to assume that w(} 

 know the force which under certain conditions seems to a lay- 

 man to be the will of the animal. But if one part only of the 

 animals moves in this definite direction and the other does not, 

 we have not succeeded in finding the force which unequivocally 

 determines the direction of their movement. 



One other point should be observed. If a sparrow flies 

 down to a seed lying on the ground, we speak of an act of will, 

 but if a dead sparrow falls upon the seed this does not appear 

 to us as such. In the latter case purely physical forces are 

 concerned, while in the former chemical reactions are also tak- 

 ing place in the sense-organs, nerves, and muscles of the animal. 

 We speak of an act of will, only when this latter complex, that 

 is, the natural movement of locomotion, plays its part also, and 



