The unity of the intellect is a philosophical theory proposed by the Muslim medieval Andalusian philosopher Averroes (1126–1198), which asserted that all humans share the same intellect. Averroes expounded his theory in his long commentary of On the Soul to explain how universal knowledge is possible within the Aristotelian theory of mind. Averroes' theory was influenced by related ideas by previous thinkers such as Aristotle, Plotinus, Al-Farabi, Avicenna (Ibn Sina) and Avempace (Ibn Bajja).