26 ARISTOTLE AS A BIOLOGIST 



through the scale of structure in living things, and so, little 

 by little, by imperceptible steps, does Nature make the 

 passage from plant, through animal, to man. It is with 

 all the knowledge, summarized in a great passage of the 

 Natural History, and embodied in this broad generaliza- 

 tion, that Aristotle afterwards proceeds to indicate the 

 same gradation in psychology, and to draw from it 

 a kindred classification of the Soul. 



There is a soul which presides over the primary physio- 

 logical requirement of nutrition, a soul already inherent in 

 the plant and inseparable from life itself ; it is ?/ TT/)(UTT? 

 X/O>XT}. Common likewise to all living things are the 

 physiological functions of growth and reproduction, and 

 the psychical agencies directing these are concomitant 

 with, and in fact identical with, the nutrient soul. Sensa- 

 tion or sensibility, whereby the animal essentially differs 

 from the plant, distinguishes the atV^rtKr/ ^vxn f the 

 sentient soul ; and the soul of movement, undisplayed in 

 the very lowest of animals, presently accompanies the 

 soul of sensibility. At length the reasoning soul, the 

 biavorjriKri ^vyji, or vov<s, emerges in man, as the source of 

 his knowledge and his wisdom. 1 In a brief but very 

 important passage, 2 with a touch of that Platonic 

 idealism never utterly forgotten by him (and so apt to 

 bring Wordsworth to our own minds), Aristotle tells us 

 that this soul ' cometh from afar ' povov OvpaOev fircuri&ai, 

 KOL 6tiov clvai fiovov. Yes, in very plain Greek prose, 

 this is no less than to assert that ' trailing clouds of glory ', 

 ' it cometh from afar.' 



But however glorified be the reasoning soul, yet these 

 parts, these subdivisions of the soul, do not stand apart in 



1 I have here borrowed some words from a former address, and from 

 my notes on the Histona Animalium. 



* De Gen. An. ii. 3, 736 b 27. Cf. Brentano, Aristoteles' Lehre vom 

 Ursprung des menschlichen Geistes, 1911, p. 18. 



