PARTS OF ANIMALS, I. i. 



that we need not concern ourselves with Soul in its 

 entirety ; because it is not Soul in its entirety that is 

 an animal's " nature," but some part or parts of it. 



Further, no abstraction can be studied by Natural 

 science, because whatever Nature makes she makes 

 to serve some purpose ; for it is evident that, even 

 as art is present in the objects produced by art, so in 

 things themselves there is some principle or cause of 

 a like sort, which came to us from the universe around 

 us, just as our material constituents (the hot, the 

 cold, etc.) did.'^ Wherefore there is better reason for 

 holding that the Heaven was brought into being by 

 some such cause — if we may assume that it came 

 into being at all — and that through that cause it 

 continues to be, than for holding the same about the 

 mortal things it contains — the animals ; at any rate, 

 there is much clearer evidence of definite ordering 

 in the heavenly bodies than there is in us ; for what 

 is mortal bears the marks of change and chance. 

 Nevertheless, there are those who affirm that, while 

 every living creature has been brought into being 

 by Nature and remains in being thereby, the heaven 

 in all its glory was constructed by mere chance 

 and came to be spontaneously, although there is no 

 evidence of chance or disorder in it. And whenever 

 there is evidently an End towards which a motion 

 goes forward unless something stands in its way, then 

 we always assert that the motion has the End for its 

 purpose. From this it is evident that something of 

 the kind really exists — that, in fact, which we call 

 " Nature," because in fact we do not find any chance 

 creature being formed from a particular seed, but A 

 comes from a, and B from b ; nor does any chance 

 seed come from any chance individual.^ Therefore 



