GENERATION OF ANIMALS, II. ni. 



plant. And it is clear we should follow a similar line 

 also in our statements about sentient Soul and 

 rational Soul, since a thing must of necessity possess 

 every one of the sorts of Soul potejitially before it 

 possesses them in actuality. And necessity requires 

 either (a) that none of them exists previously, and 

 that they all come to be formed in <the fetation) ; or 

 (b) that they are all there beforehand ; or (c) that 

 some of them are there and some are not ; and 

 further, that they come to be formed in the material 

 supplied by the female either (a) without having 

 entered in the semen of the male or (6) after having 

 so entered — that is, ha\"ing come from the male, and 

 if so, then that either (a) all of them or (6) none of 

 them or (c) some of them come to be formed within 

 the male from some outside source." Now the follow- 

 ing considerations plainly show that they cannot all be 

 present beforehand. Clearly, those principles whose 

 activity is physical cannot be present mthout a 

 physical body — there can, for example, be no walking 

 without feet * ; and this also rules out the possibiUty 

 of their entering from out side, since it is impossible 

 either that they enter by themselves, because they 

 are inseparable (from a physical body), or that they 

 enter by transmission in some body, because the 



is essentially physical (see also below, T37 a 9 f.). Thus, 

 sentient Soul, and a fortiori rational Soul, are supplied by 

 the male, through the semen, to the material provided by 

 the female. Aristotle does not, however, give any fuller 

 solution than this to his own "very difficult puzzle" how 

 and when rational Soul, which is thus supplied in a potential 

 state by the male, is actualized in the oflFspring. 



•" Aristotle takes the " locomotive Soul," the highest of the 

 " parts " or " faculties " of Soul apart from " rational Soul," 

 and shows that this cannot enter by itself ; a fortiori therefore 

 none of the lower " parts " can do so. 



169 



