Book 1
9
Now on the subject of psychology some of the teaching current in extraneous discoursesThese ἐξωτερικοὶ λόγοι are also mentioned in 6.4.2 and six other places in Aristotle (see Ross on Aristot. Met. 1076a 28). In Aristot. Pol. 1323a 22 they are appealed to for the tripartite classification of goods which in 8.2 above is ascribed to current opinion of long standing and generally accepted by students of philosophy. The phrase therefore seems to denote arguments or doctrines (whether familiar in philosophic debates, for which see note on 5.6, or actually recorded in books), that were not peculiar to the Peripatetic school; in some cases, as here, it may refer specially to the tenets of the Academy. is satisfactory, and may be adopted here: namely that the soul consists of two parts, one irrational and the other capable of reason.Literally “having a plan or principle.”
10
(Whether these two parts are really distinct in the sense that the parts of the body or of any other divisible whole are distinct, or whether though distinguishable in thought as two they are inseparable in reality, like the convex and concave sides of a curve, is a question of no importance for the matter in hand.)
11
Of the irrational part of the soul again one division appears to be common to all living things, and of a vegetative nature: I refer to the part that causes nutrition and growth; for we must assume that a vital faculty of this nature exists in all things that assimilate nourishment, including embryos—the same faculty being present also in the fully-developed organism (this is more reasonable than to assume a different nutritive faculty in the latter).
