Avicenna 980 – 1037

Avicenna, known in Arabic and Persian as Ibn Sina, was a Persian polymath of the Islamic Golden Age, regarded as one of the most influential philosophers and physicians of the medieval world. His Book of Healing is a vast philosophical and scientific encyclopedia covering logic, natural philosophy, mathematics, and metaphysics, while the Canon of Medicine served as the standard medical textbook in both the Islamic world and Latin Europe for centuries. His metaphysics distinguished essence from existence and developed an influential argument for the existence of a Necessary Being. The Floating Man thought experiment, in which a person suspended in empty space without sensory input would still be aware of the existence of the self, became a touchstone of subsequent philosophy of mind. His thought shaped both subsequent Islamic philosophy and the Latin scholastic tradition through translations into Latin in the 12th century.

Avicenna (Ibn Sina, 980–1037) was the most influential philosopher of the Islamic Golden Age and the central figure through whom Aristotelian philosophy was reshaped within the Islamic tradition. Born in Bukhara in modern Uzbekistan, he was a precocious polymath — by his own account he had memorized the Quran by ten and mastered Aristotelian logic and metaphysics by sixteen — and served as physician and minister to a series of regional rulers across Central Asia and Persia.

Avicenna's two great works are the Kitab al-Shifa (The Book of Healing), an enormous philosophical encyclopedia covering logic, natural philosophy, mathematics, and metaphysics, and the Qanun fi al-Tibb (The Canon of Medicine), the most widely-used medical textbook in Europe and the Islamic world for six centuries. The Shifa's metaphysics presents a Neoplatonic-Aristotelian synthesis: the world emanates from God in a series of necessary intermediaries, essence and existence are distinct in created beings, and the soul is essentially separate from the body.

Avicenna's philosophical innovations — the modal distinction between necessary and possible existence, the analysis of essence and existence, the doctrine of the agent intellect — shaped both Islamic philosophy and Latin scholasticism. Aquinas's metaphysics is in extended dialogue with Avicenna's. He died near Hamadan in 1037 of a chronic illness, having served as physician, philosopher, and minister to the very end.