ARISTOTLE 



iron in the making of it. The same sort of Necessity 

 applies in the works of Nature, for the Hving body 

 itself is an instrument. It is thus the final Cause 

 which necessitates the various stages of the process 

 of formation and the use of such and such material. 



Another kind of Necessity, however, makes its 

 appearance in Natural objects, and that is " simple " 

 Necessity. The mere presence of certain things in 

 a living organism entails of necessity the presence of 

 others (see 645 b 32, 677 a 17, b 22). Some results 

 follow inevitably from the very nature of the material 

 used. This " simple " Necessity can therefore be 

 regarded as a reassertion of themselves by the 

 motive and material Causes" as against the final 

 Cause. Sometimes, however, even in circumstances 

 where " simple " Necessity operates, Nature is able to 

 use the resulting products to subserve a final Cause 

 (663 b 22, 32, 677 a 15 ; see also the note on Residues, 

 p. 32). Cf. Gen. An. (Loeb), Introd. §§ 6-9- 

 Scheme of The following table will show at a glance the 

 anima s. g^j^^j^^ q£ Animals as treated of by Aristotle in the 

 De partibus : 



A. Blooded Animals 

 Man 

 Viviparous quadrupeds 



Oviparous quadrupeds 

 and footless animals 

 (reptiles and amphi- 

 bians) 



Birds 



Fishes 



B. Bloodless Animals 

 Insects 

 Testacea 

 Crustacea 

 Cephalopods 



See De gen. an. 778 b 1. 



