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. (shrink)

This article studies Ibn al-Haytham’s treatment of the common notions from Euclid’s Elements (usually referred to today as the axioms). We argue that Ibn al-Haytham initiated a new approach with regard to these foundational statements, rejecting their qualification as innate, self-evident, or primary. We suggest that Ibn al-Haytham’s engagement with experimental science, especially optics, led him to revise the framing of Euclidean common notions in a way that would fit his experimental approach.