Averroes Against Avicenna and Aquinas

In light of the main arguments directly for and against the unicity thesis, this chapter considers a final line of objection from Averroes against Avicenna’s and Aquinas’s wider alternative metaphysical theories of intellect and soul. If all three thinkers are broadly hylomorphist, how can any form (like the human soul) be separable from its matter? Furthermore, if matter is the principle of individuation for human souls (as all three thinkers accept), how can multiple intellective souls exist individuated after death? The chapter explains how both Avicenna and Aquinas respond to these objections. In fact, Aquinas appeals explicitly to Avicenna, while attempting to resist the latter’s dualism. Nevertheless, this debate highlights a further potential strength of Averroes’ simpler hylomorphic account of human beings as regular generable and corruptible material substances.