Aristotle 29 



enough for him to say that by the stroke of his tool this part 

 was formed into a concavity, that into a flat surface ; but he 

 must state the reasons why he struck his blow in such a way 

 as to effect this and what his final object was . . . [similarly] the 

 true method [of biological science] is to state what the definite 

 characters are that distinguish the animal as a whole ; to 

 explain what it is both in substance and in form, and to deal 

 after the same fashion with its several organs. ... If now this 

 something, that constitutes the form of the living being, be the 

 soul, or part of the soul, or something that, without the soul, 

 cannot exist, (as would seem to be the case, seeing at any rate 

 that when the soul departs, what is left is no longer a living 

 animal, and that none of the parts remain what they were 

 before, excepting in mere configuration, like the animals that 

 in the fable are turned into stone ;) . . . then it will come 

 within the province of the natural philosopher to inform 

 himself concerning the soul, and to treat of it, either in its 

 entirety, or, at any rate, of that part of it which constitutes 

 the essential character of an animal ; and it will be his duty to 

 say what this soul or this part of a soul is.' l Thus in the 

 Aristotelian writings the discussion of the nature and orders 

 of ' soul ' is almost inseparable from the subjects now included 

 under the term Biology. 



There can be no doubt that through much of the Aristotelian 

 writings runs a belief in a kinetic as distinct from a static. view 

 of existence. It cannot be claimed that he regarded the 

 different kinds of living things as actually passing one into 

 another, but there can- be no doubt that he fully realized that 

 the different kinds can be arranged in a series in which the 

 gradations are easy. His scheme would be something like that 

 represented on p. 30 (Fig. 73). 



' Nature,' he says, ' proceeds little by little from things 

 lifeless to animal life in such a way that it is impossible to 

 1 De partibus animalium, i. I ; 64 i a 7. 



