MEMOIR OP ARISTOTLE. 
79 
To give an analysis of the philosophical and scho- 
.astic writings of Aristotle, belongs not to a work on 
natural history. A genera] notion of their contents 
may be communicated to the reader in a brief out- 
line. The syBtem of knowledge which prevailed in 
the schools when the Stagirite began to teach, and 
in which lie bad 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 Pythagorenns 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 
