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Avicenna
Ibn Sīnā (Abū ʿAlī al-Ḥusayn ibn Sīnā)
The supreme system-builder of Islamic philosophy and medicine.
Overview
The most influential philosopher of the Islamic world, the Persian polymath Ibn Sīnā (Avicenna) built a comprehensive system spanning logic, metaphysics, physics, psychology, and medicine. His distinction between essence and existence, his proof of God as the 'Necessary Existent', his 'floating man' argument for the soul, and his theory of the intellect reshaped both Islamic and Latin philosophy. His Canon of Medicine was the standard medical text in Europe and the Islamic world for centuries.
What they supported — and why
Essence and existence
SupportedIn everything except God, essence (what a thing is) is distinct from existence (that it is); existence is 'added' to essence.
WhyWe can grasp what something is without knowing that it exists, so existence is not part of a creature's essence — it must be caused.
The Necessary Existent
SupportedEverything is either possible (needing a cause) or necessary in itself; the chain of possibles requires a Necessary Existent — God — whose essence is to exist.
WhyContingent beings cannot ground themselves, so there must be a being necessary through itself to explain all existence.
The soul and the 'floating man'
SupportedA person suspended in the void, with no sensation, would still affirm their own existence — so the self is immaterial and known directly.
WhySelf-awareness does not depend on the body or senses, showing the soul is a distinct, immaterial substance.
Causes championed
- A complete rational system
- The demonstrability of God
- The sciences of the soul and of medicine
Issues wrestled with
- How do essence and existence differ?
- How is God's existence proven?
- What is the soul?
Hurdles faced
- A turbulent life as court physician and vizier amid upheaval
- Imprisonment and repeated flight
Works & books
3 catalogued. Status shows how much survives to today.
The Book of Healing
SurvivesHis vast philosophical encyclopedia of logic, physics, mathematics, and metaphysics.
The Canon of Medicine
SurvivesThe standard medical textbook of Europe and the Islamic world for centuries.
Pointers and Reminders
SurvivesA mature, compressed statement of his logic and metaphysics.
Read the texts free
1 of Avicenna’s works are free to read in full — public-domain English editions on Project Gutenberg, matched from Gutenberg’s own catalogue.
Every edition online — Open Library catalogues 686 works & editions, 15 of them free to read in full.
The influence network
See Avicenna in the map →Influenced
In their words
“I affirm the existence of my self even while I deny my body.”
— the 'floating man' argument
Legacy
His system dominated Islamic philosophy and, translated into Latin, profoundly shaped Aquinas and medieval Europe — the pinnacle of falsafa.
Follow their questions
This thinker is a stop on these paths through philosophy.
Further reading
Cross-checked against these authoritative references.