GREEK BIOLOGY AND MEDICINE 



or rather discovering the paths of Nature's 

 ordering. Thus he was a pioneer of natural 

 science. But the intellectual needs of the 

 philosopher drove him to another and more 

 ultimate kind of pioneering. He must think 

 the matter out, and find the logical, even the 

 metaphysical basis of justification of his 

 apprehension of Nature's processes: he must 

 adjust his knowledge of Nature to the demands 

 of his thought and possibly constrain it to the 

 categories of his metaphysics. 37 Let us follow 

 him, for a little, here. 



Aristotle proceeds to attack the basic how 

 and why of living things. His treatment of 

 these organisms — that is, his biology — did 

 not call for a discussion of the world's material, 

 but merely its adaptability to nature's pur- 

 poses. But his treatment did demand a dis- 

 criminating conception of causation in order 

 to understand how plants and animals came 

 to be what they were. Although his analysis 

 of the four kinds of causes is familiar, we may 

 note the application made of it in his biology. 



" There are four causes underlying every- 

 thing: first, the final cause, that for the sake 

 of which a thing exists; secondly, the formal 

 cause, the definition of its essence (and these 

 [62] 



