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Is there a Cartesian Circle?

How do I know that what I clearly and distinctly perceive is true?

1. God exists.

2. God is the ultimate source of these perceptions.

3. God does not deceive.

How do I know that God exists?

1. What I clearly and distinctly perceive is true.

2. I clearly and distinctly perceive that God exists.

Some passages suggest the God-first idea

‘[F]rom this contemplation of the true God ... I think I can see a way forward to the knowledge of other things. To begin with, I recognize that it is impossible that God should ever deceive me. . . . And since God does not wish to deceive me, he surely did not give me the kind of faculty which would ever enable me to go wrong while using it correctly’

\citep[p.~37, AT VII:53–54]{descartes:1985_csm2}

Meditation IV

Not really convicing: does a ‘way forward’ mean a basis for knowledge?

also: doubt about clear and distinct perception

(e.g. doubt that 2+3=5)

1. It is possible to doubt things that are clearly perceived.

2. We must find justification for removing doubt.

3. Therefore, we must find justification for not doubting what is clearly perceived.

Is this a good argument. Can we reject any premises?
Matters are even clearer in the Discourse on Method ...

‘what I took just now as a rule, namely that everything we conceive very clearly and very distinctly is true, is assured only for the reasons that God is or exists

, that he is a perfect being, and that everything in us comes from him. It follows that our ideas or notions, being real things and coming from God, cannot be anything but true, in every respect in which they are clear and distinct.’

\citep[p.~130, AT VI:38]{descartes:1985_csm1}

Discourse on Method

Other passages suggest the God-first idea is wrong ...

‘I am certain that I am a thinking thing.

Do I not therefore also know what is required for my being certain about anything?

In this first item of knowledge there is simply a clear and distinct perception of what I am asserting; this would not be enough to make me certain of the truth of the matter if it could ever turn out that something which I perceived with such clarity and distinctness was false.’

‘I now seem to be able to lay it down as a general rule that

whatever I perceive clearly and distinctly is true’

Meditation III

God exists therefore clear perceptions are true

or

Clear perceptions are true therefore God exists?

Recall a key passage suggesting the God-first idea ...

‘I think I can see a way forward to the knowledge of other things ... since God does not wish to deceive me, he surely did not give me the kind of faculty which would ever enable me to go wrong while using it correctly’

\citep[p.~37, AT VII:53–54]{descartes:1985_csm2}

Meditation IV

‘there arises in me a clear and distinct idea of a being who is independent and complete, that is, an idea of God.

And from the mere fact that there is such an idea within me [...] I clearly infer that God also exists [...]

So clear is this conclusion that I am confident that the human intellect cannot know anything that is more evident or more certain.’

Meditation VI

I think Descartes’ strategy might be this ...

1. If we can know anything, then we can know God exists.

2. We can know something.

3. Therefore, we can know God exists.

4. But God doesn’t deceive us.

5. Therefore what we clearly perceive is true.

On my interpretation, Descartes is not offering an anti-sceptical argument.
Steve’s rough idea: \begin{enumerate} \item If we can know anything, then we can know God exists. \item We can know something. \item Therefore, we can know God exists. \item But God doesn’t deceive us. \item Therefore what we clearly perceive is true. \end{enumerate} Compare \citet{murdoch:1999_cartesian}: ‘not only is the doubt-insinuating thought not a reason for Descartes to doubt his entitlement to infer that God exists, but also he has no other reason to doubt this.’ Conflicting interpretations include \citet{rocca:2005_descartes,broughton:2003_descartes,doney:1955_cartesian}.
On my interpretation, there’s also no reason for Descartes to be offering a sceptical argument.

Two Interpretations

1. The sciences need a metaphysical foundation.

2. This foundation must include a refutation of scepticism.

‘I had seen many ancient writings by the Academics and Sceptics on this subject, and was reluctant to reheat and serve this precooked material’

Second Replies

1. The assumption that sensory perception enables us to know the essential nature of things leads to bad science.

2. Reflection on possible grounds for doubt provides reasons to reject this assumption.

This is why doubt is necessary to establish anything in the sciences that is stable and likely to last.

If Descartes were refuting scepticism, the Cartesian Circle would be inescapable.

But it isn’t.

So Descartes isn’t refuting scepticism.

... or?

This passage appears to refute my position.
Actually it’s doubly bad for me (a) knowledge depends on God, and (b) it’s not knowledge if it can be doubted.

’an atheist can be clearly aware that the three angles of a triangle are equal to two right angles [...]. But I maintain that this awareness of his is not true knowledge, since no act of awareness that can be rendered doubtful seems fit to be called knowledge’

\citep[p.~101, AT VII: 141]{descartes:1985_csm2}

Second Replies

Also note what Descartes himself said ...
‘as to the fact that I was not guilty of circularity when I said that the only reason we have for being sure that what we clearly and distinctly perceive is true is the fact that God exists, but that we are sure that God exists only because we perceive this clearly: [...] I made a distinction between what we in fact perceive clearly and what we remember having perceived clearly on a previous occasion. To begin with, we are sure that God exists because we attend to the arguments which prove this; but subsequently it is enough for us to remember that we perceived something clearly in order for us to be certain that it is true. This would not be sufficient if we did not know that God exists and is not a deceiver’ \citep[p.~171, AT VII:245--6]{descartes:1985_csm2}