Antoine ArnauldI can’t see anywhere in the entire work an argument that could serve to prove this claim, apart from what is laid down at the start [this isn’t an exact quotation from the Meditations]:‘I can deny that any body exists, or that anything is extended, but while I am thus denying, or thinking, it goes on being certain to me that I exist. Thus, I am a thinking thing, not a body, and body doesn’t come into the knowledge I have of myself.’
But so far as I can see, all that follows from this is that I can obtain some knowledge of myself without knowledge of the body. But it isn’t clear to me that this knowledge is complete and adequate, enabling me to be certain that I’m not mistaken in excluding body from my essence. I’ll explain through an example.
Suppose someone knows for certain that the angle in a semicircle is a right angle, and thus that this angle and the diameter of the circle form a right-angled triangle. In spite of knowing this, he may doubt, or not yet have grasped for certain, that the square on the hypotenuse equals the sum of the squares on the other two sides; indeed he may even deny this if he has been misled by some fallacy. (For brevity’s sake, I’ll express this as ‘the triangle’s having the property P’.) But now, if he argues in the same way that Descartes does, he may appear to have confirmation of his false belief, as follows: ‘I vividly and clearly perceive that the triangle is right-angled; but I doubt that it has the property P; therefore it doesn’t belong to the essence of the triangle that it has the property P.’
Again, even if I deny that the square on the hypotenuse equals the sum of the squares on the other two sides, I still remain sure that the triangle is right-angled—my mind retains the vivid and clear knowledge that one of its angles is a right angle. And given that this is so, not even God could bring it about that the triangle is not right-angled. Therefore, I might argue, the property P that I can doubt—or indeed that I can remove—while leaving my idea of the triangle intact doesn’t belong to the essence of the triangle. Now look again at what Descartes says:
‘I know that if I have a vivid and clear thought of something, God could have created it in a way that exactly corresponds to my thought. So the fact that I can vividly and clearly think of one thing apart from another assures me that the two things are distinct from one another, since they can be separated by God.’
I vividly and clearly understand that this triangle is right-angled, without understanding that the triangle has the property P. It follows, on Descartes’s pattern of reasoning, that God at least could create a right-angled triangle with the square on its hypotenuse not equal to the sum of the squares on the other sides!
The only possible reply to this that I can see is to say that the man in this example doesn’t vividly and clearly perceive that the triangle is right-angled. But how is my perception of the nature of my mind any clearer than his perception of the nature of the triangle?
Now although the man in the example vividly and clearly knows that the triangle is right-angled, he is wrong in thinking that property P doesn’t belong to the nature or essence of the triangle. Similarly, although I vividly and clearly know my nature to be something that thinks, mightn’t I also be wrong in thinking that nothing else belongs to my nature apart from my being a thinking thing? Perhaps my being an extended thing also belongs to my nature.
1. Which premise of the Sixth Meditation argument for the real distinction does Arnauld challenge? What is theproblem with it?
Descartes Although we can vividly and clearly understand that a triangle in a semicircle is right-angled without being aware of its having property P, we cannot have a clear understanding of a triangle’s having property P without at the same time taking in that it is right-angled. In contrast with that, we can vividly and clearly perceive the mind without the body and the body without the mind.And although it is possible to have a concept of triangle inscribed in a semicircle that doesn’t include the triangle’s having property P, i.e., equality between the square on the hypotenuse and the sum of the squares on the other sides, it is not possible to have a concept of triangle inscribed in a semicircle that does include there being no ratio at all between the square on the hypotenuse and the squares on the other sides. Hence, though we may be unaware of what the ratio is, we can’t rule out any candidate unless we clearly understand that it is wrong for the triangle; and we can’t clearly understand this for the ratio equality, because it is right for the triangle. So the concept in question must, in an indirect and oblique way, involve the property P: it must involve a thought of ‘some ratio or other’ which could take the value equality. In contrast with this, the concept of body doesn’t include—or even indirectly and obliquely involve—anything at all that belongs to the mind, and the concept of mind doesn’t include—or even indirectly and obliquely involve—anything at all that belongs to the body.