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ArgumentThe argument from the indivisibility of mind
The body is made of parts, thought has none: what thinks cannot therefore be identical with what is extended.
Supports
Descartes · · 1641
- Whatever is material is divisible: a body, an organ, a brain can be parted, and each part is still something extended. That is what it means, for a thing, to occupy space.
- What thinks is not parted in that way: when I deliberate, I do not find one half of me doubting and another willing, but a single subject that doubts, wills and feels. Removing a part of a thought does not leave a smaller thought, it leaves nothing.
- Yet two things that do not share the same properties cannot be one and the same: if one divides and the other does not, then there are two.
Therefore So what thinks in me is not what is extended: mind is a reality of another kind, and its dependence on the body does not prove it to be a part of it: this is the thesis of substance .
How far does this reasoning convince you?
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Deepenings
Half a consciousness?
- One can lose sight, memory, speech: the experience that remains is impoverished in content, never cut in two. A blind person does not have half a consciousness, but a consciousness without images.
- What divides, then, are the faculties and their objects, never the one to whom all this happens: I cannot so much as picture what half a subject would be, whereas I picture half a brain without difficulty.
Therefore Indivisibility bears not on the mind's content, which varies and diminishes, but on the subject that undergoes it.
How far does this reasoning convince you?
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The argument from clear conception
- The argument is not the fallacy ascribed to it ("I doubt my body, I do not doubt my thought, so they differ"): what I doubt says nothing of what is, as is shown by the man who doubts that the masked stranger is his brother when he is.
- What advances is stronger: I have a complete idea of thought, into which nothing of extension enters, and a complete idea of extension, into which nothing of thought enters. These are not two aspects of one thing, but two natures each of which is conceived whole without the other.
- But what is conceived separately in this way can exist separately, at least for a power that would need only to will it: nothing in the nature of thought requires a body.
Therefore So soul and body are really distinct: either could subsist without the other, whatever be the case with their present union.
How far does this reasoning convince you?
Not at all
Entirely
Put to the test