The Book of Healing
Avicenna’s largest philosophical summa reworks the whole Aristotelian curriculum in four parts: logic, from Porphyry’s Isagoge to the Poetics; natural philosophy, including the influential book On the Soul; the mathematical sciences; and a metaphysics that studies being as being and culminates in the Necessary Existent, prophecy and the political order.
Understanding the text
Begun at Hamadan at the request of his students and completed at Isfahan around 1027, the work was reportedly written in part without any books to hand. In the twelfth century its books on the soul and on metaphysics were translated into Latin at Toledo, where they lastingly reshaped scholastic philosophy.
Key points
- 01
Essence and existence
The metaphysics distinguishes what a thing is from the fact that it exists; no caused being has its existence from its essence alone.
- 02
Necessary Existent
Whatever is possible in itself needs a cause, so the whole chain of possible beings depends on a being necessary through itself, which is one and simple.
- 03
The floating man
The book On the Soul imagines a man created all at once in the air, with no sensation of his body, who would still affirm his own existence; the soul therefore knows itself apart from the body.
Explore the ideas in depth
Essence, existence and the Necessary
Follow how the Book of Healing separates what a thing is from its existence and climbs from possible beings to a single Necessary Existent.
Situating the text
Begun at Hamadan at the request of his students and completed at Isfahan around 1027, the work was reportedly written in part without any books to hand. In the twelfth century its books on the soul and on metaphysics were translated into Latin at Toledo, where they lastingly reshaped scholastic philosophy. Avicenna’s largest philosophical summa reworks the whole Aristotelian curriculum in four parts: logic, from Porphyry’s Isagoge to the Poetics; natural philosophy, including the influential book On the Soul; the mathematical sciences; and a metaphysics that studies being as being and culminates in the Necessary Existent, prophecy and the political order.
Following the arguments
Essence and existence : The metaphysics distinguishes what a thing is from the fact that it exists; no caused being has its existence from its essence alone. Necessary Existent : Whatever is possible in itself needs a cause, so the whole chain of possible beings depends on a being necessary through itself, which is one and simple. The floating man : The book On the Soul imagines a man created all at once in the air, with no sensation of his body, who would still affirm his own existence; the soul therefore knows itself apart from the body.
Continuing the reading
Begin with the first treatise of the Metaphysics, on the subject of first philosophy and the primary notions of the existent, the thing and the necessary, then read the opening chapter of On the Soul for the floating man. Begun at Hamadan at the request of his students and completed at Isfahan around 1027, the work was reportedly written in part without any books to hand. In the twelfth century its books on the soul and on metaphysics were translated into Latin at Toledo, where they lastingly reshaped scholastic philosophy.
Questions to carry into your reading
- Why, for Avicenna, does existence not follow from what a thing is?
- How can the argument from possible beings work even if the world has no first moment?
For Avicenna, everything except the Necessary Existent owes its existence to another, even in a world without beginning.
How to read it
Begin with the first treatise of the Metaphysics, on the subject of first philosophy and the primary notions of the existent, the thing and the necessary, then read the opening chapter of On the Soul for the floating man.
Editions & sources
Summaries and key points are original editorial interpretations. They accompany reading the work and do not replace an edition of the text. Editorial method →