 Avicenna did not see himself in Aristotle’s debt and his science of the Divine Matters, what may be translated as metaphysics, contained an original doctrine of being. Avicenna allocated a role to the metaphysician in proving the existence of Nature or the composition of matter and form in bodies and Averroes did not admit such a role. Averroes’ tense relationship with Avicenna shows up also in their disagreement upon the existence of corporeal form, or on the extent of necessity in Nature.