The early albertus Magnus and his arabic sources on the theory of the soul

Albertus Magnus favours the Aristotelian definition of the soul as the first actuality or perfection of a natural body having life potentially. But he interprets Aristotle's vocabulary in a way that it becomes compatible with the separability of the soul from the body. The term “perfectio” is understood as referring to the soul's activity only, not to its essence. The term “forma” is avoided as inadequate for defining the soul's essence. The soul is understood as a substance which exists independently of its actions and its body. The article shows that Albertus' terminological decisions continue a tradition reaching from the Greek commentators, and John Philoponos in particular, to Avicenna. Albertus' position on another important issue is also influenced by Arabic sources. His defense of the unity of the soul's vegetative, animal and rational parts rests on arguments from Avicenna and Averroes. It is shown that Averroes' position on the problem is not clearcut: he advocates the unity thesis, but also teaches the plurality of the generic and individual forms in man. This double stance is visible in the Latin reception of Averroes' works, and also in Albertus, who presents Averroes both as supporter and opponent of the plurality thesis.