Metaphysics

The Book of Knowledge

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Avicenna

c. 1023

The Book of Knowledge — Danishnama-i 'Ala'i — holds the distinction of being the first major philosophical work written in the Persian language rather than Arabic, composed at the request of the Buyid prince 'Ala' al-Dawla. It covers the four standard divisions of Aristotelian philosophy — logic, natural philosophy, mathematics, and metaphysics — in a more accessible style than the Book of Healing, and served as an introduction to Avicenna's system for Persian-speaking audiences. The metaphysical sections are particularly notable for Avicenna's development of the distinction between necessary and contingent existence: while everything that exists might not have existed, one being — God — must exist of itself, its existence identical with its essence. This argument became fundamental to Islamic philosophical theology and influenced Aquinas's Five Ways. The Book of Knowledge is also the source of important statements on the soul and immortality that circulated widely in the medieval world.