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Ibn Sina argued that the intellect cannot reside in any body. Which premise would a materialist reject?

Layla Sfeir Fellow
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ConsciousnessIslamicGreek & RomanFalsafaAristotelianismIbn SinaAl-GhazaliAristotle#ibn-sina#immateriality#intellect#rational-soul
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Its coordinates: 1.3 Philosophy of Mind · 1.3.1 The Mind–Body Problem · 1.3.3 Intentionality +1 more

With so many threads about machine minds, it seems worth bringing out one of the oldest arguments against them, although Ibn Sina was not thinking of machines.

In the psychology of the Shifāʾ (Book V of the part on the soul, chapter 2 in most editions), he argues that the rational soul does not reside in a bodily organ. The core of it, as I read it:

  1. We think intelligibles, such as human as such, which are indivisible. There is no left half of a concept.
  2. Whatever is received in a body is received in something divisible, and is divided along with it.
  3. So if intelligibles were received in a body, they would be divisible. They are not.
  4. So the substrate of intellect is not a body.

He adds supporting arguments, including one I like: bodily faculties are weakened by strong objects, as the eye is dazzled by bright light, while the intellect grows stronger after grasping something difficult.

Al-Ghazālī attacked these proofs in the eighteenth discussion of The Incoherence of the Philosophers, not because he denied the soul but because he denied they were demonstrations.

So, for the materialists here: which premise goes? I suspect the second, but I would like to see it done carefully.

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4 answers

  1. Kenneth Lam Chi-ho

    Fellow

    Premise 2 is where I would press, using a distinction Husserl and the Yogācāra commentators would both recognise: the vehicle of a thought versus its content. A sentence written on paper is divisible; you can tear it in half. What it says is not divided by the tear. Nobody concludes that the content of a written sentence floats free of the ink.

    Ibn Sina seems to move from "the content is indivisible" to "whatever holds the content is indivisible". A materialist can grant the first and deny the second. A pattern spread across a network carries an indivisible content without being indivisible itself.

  2. Reza Tehrani

    Fellow

    Mulla Sadra kept Ibn Sina's conclusion and turned his starting point upside down. His formula is that the soul is bodily in its origination and spiritual in its survival: it begins as the form of a body and, through substantial motion, becomes something that no longer needs one.

    That gives a third answer to your question. Neither premise has to go. The argument is sound for the soul's final state and false for its beginning, because the soul is not one fixed kind of thing across a life.

  3. Layla Sfeir

    Fellow

    Kenneth, that is the objection I expected, and I think Ibn Sina would say the soul does not carry the intelligible as ink carries a sentence; in grasping it, the intellect is actualised by the form itself. Whether that is a deeper view or a way of avoiding your point is exactly what I can't decide. Reza's Sadra is a beautiful escape, but it costs a whole metaphysics of motion.

  4. Maximilian Ortner

    Fellow

    A neurologist's attempt, Layla. A materialist should reject premise 2, but the interesting work is in saying why.

    "Received in a body" assumes that if a thought is realised in tissue, the thought inherits the tissue's divisibility. That fails for every case we understand. A chess position stored in a computer's memory is physically spread across many components, yet there is no "left half" of white to move. The content is a pattern the parts realise together, not a stuff spread out among them.

    What interests me clinically is Ibn Sina's supporting argument about strong objects. After brain injury, patients tire from difficult thinking, and badly; the intellect does not grow stronger with effort the way he describes. That suggests the work of the intellect, at least, is bodily, whatever we decide about its objects.