MEMOIR OF ARISTOTLE. 79 



To give an analysis of the philosophical and scho- 

 -astic writings of Aristotle, belongs not to a work on 

 natural history. A general notion of their contents 

 may be communicated to the reader in a brief out- 

 /ine. The system of knowledge which prevailed in 

 the schools when the Stagirite began to teach, and 

 in which he had himself been trained, was not such 

 as was likely to satisfy his penetrating mind. It 

 was, in fact, a vast undigested scheme of theoretical 

 wisdom, jumbled together without order, and fluc- 

 tuating in its form and character, according to the 

 talents and circumstances of its leading professors. 

 The Pythagoreans blended physical, mathematical, 

 and moral truth in mystic combination, as exhibited 

 in the mythology of Egypt. In the hands of So- 

 crates, philosophy assumed a more ethical com- 

 plexion ; but the fanciful imagination of Plato in- 

 vested it once more with a mixed character, by em- 

 bodying in one compressed view the various preceding 

 systems. Considering that definitions could not ap- 

 ply to every perceptible object, if (according to 

 the doctrine of Heraclitus) all such objects were 

 constantly changing ; and that numbers (as taught by 

 Pythagoras) could not sufficiently account for that 

 immense variety of objects which the universe pre- 

 sented, he concluded that there must be some exist- 

 ences, independent of the perceptible universe, to 

 serve as the objects of definitions. Hence his famous 

 doctrine of Ideas, or archetypes, corresponding to the 

 different classes of external objects ; and to these 



