252 SHEiLAH o'flynn brennan 



insofar as a thing does not have its nature unless it has the 

 form " by which we define what the thing is." This form might 

 appear to be the essence, taken absolutely, without reference 

 to movement, unless we bear in mind what has gone before. 

 For Aristotle not only defined nature as a principle of move- 

 ment but also stated that those things are said to have a nature 

 which have this principle. Accordingly, the form must be taken 

 as nature precisely because, in making the thing to be what it 

 is, it is the root of its particular activities and its particular 

 tendencies to change. It is in this sense that the thing would 

 not have a nature if it did not have a form. 



But there is another sense in which the form is nature. The 

 natural thing is one that is the result of change, the product of 

 a natural process of becoming (which, according to Aristotle, 

 was also called ^vo-i?) . The form of a natural being is one that 

 fulfills a potency of matter, and it was to this form that the 

 matter tended in the process of generation. The form, then, 

 as nature, is also an end of movement: " What grows qua 

 growing grows from something into something. Into what then 

 does it grow.? . . . Into that to which it tends. The form then 

 is nature." "^ In time, it is true, the form is at the term of 

 generation, but, absolutely considered, it is a principle, and a 

 principle prior to the matter according to the essential order 

 of things. The form, consequently, whether it be considered as 

 the origin of activity or as the end of generation, is nature 

 as a principle of movement. (It can also, of course, be nature 

 as the active principle in the progenitor jrom which generation 

 proceeds. But this sense, mentioned in the passage from the 

 Metaphysics and indicated at least at one point in Chapter 2, 

 Book n, of the Physics,^ belongs properly to a later stage in 

 the philosophy of nature, that which deals with the living 

 natural being as such.) 



'Aristotle, Physics, Bk II, ch. 1, 193b 17 et sqq. 



* " Man is born from man, but not bed from bed. That is why it is said that 

 not the shape but the wood is the nature of the bed, for, if the bed sprouted, 

 not a bed but wood would come up. But if the form is art, so also is the form 

 nature; for man is born from man." Physics, Bk. II, ch. 1, 193 h 9 et sqq. 



