The Book of Healing

An extensive encyclopedia by the Persian polymath Avicenna, covering logic, natural sciences, mathematics, and metaphysics. Despite its title, it is a work of philosophy and science, not medicine.

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Aristotelianism: A philosophical tradition based on Aristotle’s works and their later interpretation. Avicenna adopts and revises Aristotelian ideas across the encyclopedia.
Avicennian logic: Avicenna’s account of logic as a system of concepts, propositions, and forms of inference. The opening logical sections establish methods used throughout the work.
Avicenna: A Persian polymath whose works shaped philosophy and medicine across the Islamic world and medieval Europe. He composed the encyclopedia as part of his broader philosophical project.
Islamic philosophy: Philosophical inquiry developed by thinkers in the Islamic world, often engaging Greek traditions and Islamic theology. Avicenna’s system became one of its most influential and enduring forms.
Avicenna’s Flying Man: A thought experiment in which a person suspended without sensory contact is imagined to remain aware of their own existence. The psychology section uses it to argue that self-awareness does not depend on bodily sensation.
Peripatetic school: A tradition of philosophy originating with Aristotle and developed by his followers. The work belongs to the tradition Avicenna transformed for the medieval Islamic world.
Demonstration (logic): A deductive argument that produces knowledge through premises that are true, primary, and explanatory. Avicenna presents demonstration as the highest form of scientific reasoning.
Al-Farabi: A tenth-century philosopher who adapted Greek philosophy and influenced later Islamic thinkers. His account of logic and the sciences helped form the intellectual background Avicenna inherited.
Avicennism: The philosophical tradition that developed, adapted, or opposed Avicenna’s doctrines. The encyclopedia became a principal source for this tradition’s concepts and disputes.
Avicenna’s argument for the Necessary Existent: An argument from the distinction between contingent and necessary existence to a being that exists through itself. The metaphysics section develops this proof as an account of the first principle.