Active Intellect - Aristotle

Aristotle

The active intellect was the subject of intense discussion in medieval philosophy. The idea is first encountered in Aristotle's De Anima, Book III. Following is the translation of one of those passages (De Anima, Bk. III, ch. 5, 430a10-25) by Joe Sachs, with some notes about the Greek. Sachs comments that "it is the source of a massive amount of commentary and of fierce disagreement":

...since in nature one thing is the material (hulē) for each kind genos (this is what is in potency all the particular things of that kind) but it is something else that is the causal and productive thing by which all of them are formed, as is the case with an art in relation to its material, it is necessary in the soul (psuchē) too that these distinct aspects be present;

the one sort is intellect (nous) by becoming all things, the other sort by forming all things, in the way an active condition (hexis) like light too makes the colors that are in potency be at work as colors (to phōs poiei ta dunamei onta chrōmata energeiai chrōmata).

This sort of intellect is separate, as well as being without attributes and unmixed, since it is by its thinghood a being-at-work, for what acts is always distinguished in stature above what is acted upon, as a governing source is above the material it works on.

Knowledge (epistēmē), in its being-at-work, is the same as the thing it knows, and while knowledge in potency comes first in time in any one knower, in the whole of things it does not take precedence even in time.

This does not mean that at one time it thinks but at another time it does not think, but when separated it is just exactly what it is, and this alone is deathless and everlasting (though we have no memory, because this sort of intellect is not acted upon, while the sort that is acted upon is destructible), and without this nothing thinks.

The passage tries to explain "how the human intellect passes from its original state, in which it does not think, to a subsequent state, in which it does." He inferred that the energeia/dunamis distinction must also exist in the soul itself. Aristotle says that the passive intellect receives the intelligible forms of things, but that the active intellect is required to make the potential knowledge into actual knowledge, in the same way that light makes potential colors into actual colors.

The passage is often read together with Metaphysics, Book XII, ch.7-10, where Aristotle also discusses the human mind and distinguishes between the active and passive intellects. In that passage Aristotle appears to equate the active intellect with the "unmoved mover" and God.

This has been referred to as "the most intensely studied sentences in the history of philosophy". As Davidson remarks:

Just what Aristotle meant by potential intellect and active intellect - terms not even explicit in the De anima and at best implied - and just how he understood the interaction between them remains moot. Students of the history of philosophy continue to debate Aristotle's intent, particularly the question whether he considered the active intellect to be an aspect of the human soul or an entity existing independently of man.