He explains that when people have real knowledge, their thinking is, for a time receiving, or partaking of, this energeia of the nous (active intellect).
[3] Sachs comments that the nature of the active intellect was "the source of a massive amount of commentary and of fierce disagreement"; elsewhere, chapter 5 of De Anima has been referred to as "the most intensely studied sentences in the history of philosophy.
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.
[4] The reason for positing a single external Agent Intellect is that all (rational) human beings are considered by Aristotelians to possess or have access to a fixed and stable set of concepts, a unified correct knowledge of the universe.
[5] The more strict Aristotelians, Avempace and Averroes, wrote about how one could conjoin oneself with the active intellect, thus attaining a kind of philosophical enlightenment.
In Medieval and Renaissance Europe some thinkers, such as Siger of Brabant, adopted the interpretation of Averroes on every point, as did the later school of "Paduan Averroists".