QuestionsIs the mind the brain?Mind distinct from body
Is the mind the brain?The mind is not matter

Mind distinct from body

René Descartes 1596 · 1650Doubt everything to find what survives doubt.
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What it claims

My mind is really distinct from my body, and can exist without it.

Why

I clearly conceive my mind without body and body without thought; two things that can exist apart are distinct.

In short

"Mind distinct from body" is an argument by René Descartes (Meditation VI) on the question "Is the mind the brain?" (answer: the mind is not matter). Its claim: My mind is really distinct from my body, and can exist without it. According to AskPhilosophy's logic check (Z3 solver), the conclusion does follow from its 3 premises. AskPhilosophy presents 4 objections, 3 of them with a documented reply, and the original text behind each premise, checked word for word.

Meditation VI
Valid

In the Sixth Meditation, Descartes sets out to prove that the mind is a substance really distinct from the body, and could exist without it.

P1Whatever I conceive [[idee-claire-distincte|clearly and distinctly]] can be made by God as I conceive it: if I conceive two things apart, they can exist apart.
P2I clearly conceive my mind as a thinking, unextended thing, and my body as an extended, unthinking thing.
P3If two things can exist without each other, they are not one and the same thing.
Therefore my mind is really distinct from my body, and can exist without it.

click a premise to reject it

If you accept every premise, logic forces you to accept the conclusion. So the debate is about the premises.
Checked by a logic solver: the premises cannot all be true while the conclusion is false.
The three premises suffice and each one is essential. To reject the conclusion you must reject at least one premise, almost always P1 or P2.
Analogy. If an architect can clearly draw two rooms with no door between them, nothing prevents an all-powerful builder from building them apart. Descartes reasons the same way: what I conceive apart, God can make exist apart.

Objections

4

Each objection is a conversation: click to see who replies and where the debate stands.

A
Arnauld 1641 · attacks premise 2

I can clearly conceive a right triangle without knowing that the square on its hypotenuse equals the sum of the squares on the sides. Yet it cannot exist without that property. So conceiving apart does not prove existing apart: my conception of the mind may simply be incomplete.

Descartes replies
Descartes
The triangle is not a complete thing on its own, whereas the mind is conceived as a complete thing, borrowing nothing from the body.
Hobbes 1641 · attacks premise 2

Thinking is an act, and every act has a subject. Nothing prevents that thinking subject from being a body: Descartes assumes otherwise without proof.

Descartes replies
Descartes
The subject of thought is indeed a substance, a "metaphysical matter" if you like, but not therefore a body. And I assumed nothing: the question stays open until the Sixth Meditation, where it is proved.
T
The "masked man" 1950 · attacks premise 1

Lois Lane can conceive Clark Kent without Superman; yet they are the same person. What I can conceive depends on what I know, not on what things are. If the mind really is the brain, I can be unaware of it and "conceive" them apart. (A modern objection, made by several 20th-century critics.)

no reply
summary: their text is not yet in our corpus
No reply possible: objection raised in 1950, after the author's death (1650).
E
Elisabeth of Bohemia 1643 · attacks the conclusion

If the soul has no extension, how can it move the body? Pushing requires contact, and contact requires extension. The conclusion makes the union of soul and body unintelligible.

Descartes replies
Descartes
We have primitive notions: for the soul, thought; for the body, extension; for both together, their union, on which depends the soul's power to move the body. This union is not understood by meditating but by living.
What today's voices say
Criticize it
Daniel DennettAt 17 he found Descartes's dualism 'beautiful, but it's wrong', and spent his career explaining why. He calls the pull of the inner witness 'Cartesian gravity'.
Robert SapolskyHe says Descartes was wrong: animals and humans alike are biological machines, only humans are more complicated.