THE MAIN GROUPS OF ANIMALS. 



Aristotle has left us no systematic classification of animals. It will 

 nevertheless be convenient to arrange the chief groups recognised by 

 him in a tabular form ; and the form which seems most consistent with 

 his views is that in which these groups are placed in linear series, 

 according to their supposed degrees of excellence. 



Before, however, doing this, it will be well to consider very briefly 

 what Aristotle means when he speaks, as he so often does, of one animal 

 being superior to or more noble than another ; and also to enquire what 

 were the external characters by which he thought such superiority could 

 be recognised. When we have done this, we can proceed to apply 

 Aristotle's tests of comparative excellence to his various groups with the 

 fair expectation of being able to arrange them in much the same order 

 as he would himself have done. 



(i). The basis of all excellence is the presence of a soul, that is, the 

 possession of life. " Anything nobler or better than the soul cannot 

 possibly exist ;"^ and again, "to be is better than not to be ; to live 

 than not to live ; things with a soul than things without ; the soul itself 

 than the body." ^ As things that live are superior to things that are* 

 lifeless, so also things with much life are superior to things with little^ 

 " Souls differ from each other in their degrees of honour ; " ^ and the 

 difference is thus set forth. " The faculties of the soul are many ; and 

 though everything that lives has a soul, yet have not all souls all these 

 faculties. In some souls there is but one faculty, in others several, in 

 some all. The faculties are the Nutritive, the Sensitive, the Appetitive, 

 the Motor, the Intellectual. In plants there is no other faculty than the 

 Nutritive, but in all animals there is not only this, but the Sensitive, and, 

 as a necessary consequence, the Appetitive as well. Some animals there 

 are, again, that possess also the Motor faculty ; and a few, such as man 

 and any other creature, if such there be, that equals or surpasses him in 



' De Anima, i. 5, 15. ^ De Gen. ii. i, 2. ^ De Gen. ii. 3, 11. 



