Avicennism
1000 – 1400
Ibn Sina's system taken as a school: essence apart from existence, a necessary being at the end of every chain of causes, and an immaterial intellect.
- Active
- 1000 – 1400
- Where
- Persia, then the Latin universities
- Status
- extinct as a school, absorbed everywhere
- Tradition
- Islamic
The claim
Consider a triangle. Its essence tells you nothing about whether any triangle exists. Existence is therefore something added to essence in everything except one being, whose essence is existence, and from which everything else must come.
What it held
Avicennism is what happens when one philosopher's system becomes a research programme other people work inside. The distinction it rests on had no Greek equivalent, and once made it is hard to unsee.
From it follows the proof of the Necessary Existent, which is not an argument from a first event in time. Every contingent thing needs a cause of its existing now; a chain of such things is itself contingent however long; so there must be something not contingent. It works whether or not the world had a beginning, which is why it survived the medieval arguments about eternity intact.
The psychology is equally consequential. The flying man — suspended in void, no sensation, no memory of a body — would still be certain of himself, from which Ibn Sina argues that the soul is not the body and is known immediately.
In Latin, translated at Toledo, he became simply Avicenna and was argued with as a living opponent for three centuries. In Persian, he became the framework everything after had to modify.
How it argued
Demonstration from definitions and distinctions, with thought experiments used to isolate what can be known independently of the senses.
What it was arguing against
Those who make existence a part of what a thing is, and the theologians who denied that reason could establish anything about God.
Where it disagreed with itself
Whether existence is really distinct from essence or only conceptually — Averroes said Ibn Sina had confused a grammatical fact for a metaphysical one, and the argument reaches Aquinas and Scotus intact.
Common misconceptions
That the flying man is a version of the cogito. Ibn Sina is arguing for the soul's immateriality rather than establishing a first certainty against doubt, and there is no sceptical problem in the background.
How it began
Ibn Sina was a practising physician and administrator who wrote most of this while travelling, in prison, or between political posts, and reportedly composed at speed from memory.
What became of it
Attacked by al-Ghazali, defended and revised in Persia, and in Latin Europe absorbed so thoroughly that the vocabulary stopped being recognised as his.
Lasting influence
Aquinas' central distinction is Avicennian. Scotus' univocity is a response to him. His medical Canon was a European textbook into the seventeenth century.
Why it still matters
Contingency arguments for a necessary being are still the strongest form of natural theology, and they are his rather than Aquinas'.
Put another way
A triangle you can define completely without knowing whether one exists.
Where to start
The flying-man passage, then the proof of the Necessary Existent. Both are short and both are the whole system in miniature.
The surprising bit
The Canon of Medicine was still being taught at Montpellier and Padua six hundred years after he wrote it, which makes him one of the longest-serving textbook authors in history.
In their own words
Existence is an accident occurring to essence.
He would not affirm the existence of his limbs, yet he would affirm the existence of himself.
Connections
- Answers
- Falsafa
The verdict
A single mind whose distinctions became the furniture of three philosophical traditions.