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Descartes ends the first Meditation worried that his decision to throw out of his box of beliefs everything that could be doubted has left him with an empty box.
He has considered the insane, whose senses give them absolute certainties, only different certainties that others feel; he has considered the possibility that he is simply dreaming; and, most powerfully of all, he has put the possibility of God, or an evil demon, simply deceiving us at every point.
Does this empty the box completely?
He then purports to notice that it does not, and presents perhaps the most renowned observation in the whole of philosophy: what is known with fond familiarity as 'the cogito'.
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In Meditation 2 he puts the point like this. He says his method of doubt has convinced him that there is no reason to think there is anything in the world - sky, earth, minds, bodies. But 'if I convinced myself of something then I certainly existed'. (p.80)
Certainty that I myself exist thus survives even the thought of the evil demon, which demolishes everything else. Even on that hypothesis, 'I too undoubtedly exist', even if he is deceiving me; and let him deceive me as much as he can, he will never bring it about that I am nothing so long as I think that I am something.'
Descartes concludes:
'So after considering everything very thoroughly, I must finally conclude that this proposition, I am, I exist, is necessarily true whenever it is put forward by me or conceived in my mind.'
This way of putting it is not quite how he puts it elsewhere, in the Discourse on Method. It is there that the more famous formulation occurs:
I think, therefore I am
(or,
as Cottingham has it, 'I am thinking, therefore I exist'):
'... I noticed that while I was endeavouring ... to think that everything was false, it was necessary that I, who was thinking this, was something. And observing that this truth 'I am thinking, therefore I exist' was so firm and sure that all the most extravagant suppositions of the sceptics were incapable of shaking it, I decided that I could accept it without scruple as the first principle of the philosophy I was seeking.' Discourse; Cottingham, p. 36. e-text.
| Footnote on Descartes' discussion of nutrition and movement. |
Having brought out that to doubt anything at all 'I' must exist, Descartes immediately goes on to ask what this 'I' can mean.
'I am, I exist - that is certain. But for how long?' (p.82) Descartes asks.
His answer is:
'For as long as I am thinking ...' p.82.
This is what he thinks the 'I' must mean in the bedrock certainty 'I exist'.
'I am, then, in the strict sense only a thing that thinks.' p.82.
He explores what thinking is. A thing that thinks, he says, is one that
'doubts, understands, affirms, denies, is willing, is unwilling, and also imagines and has sensory perceptions.'
For Descartes, our thoughts are limited to states of which we are conscious [MORE]
(By sensory perceptions he means something like having sense data - the experience without the implication it has a reference to what is external to.)
So that is one large question: what exactly is the 'I' the existence of which he can be certain?
The Cogito
I AM THINKING THEREFORE I EXIST
The other is the source of the compelling character of the Cogito.
One suggestion is that it is 'self-validating': saying or thinking it makes it true.
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Prompt: Can you think of other statements that might be like that? |
Here is Scruton explaining 'self-validation':
"According to Descartes this proposition ('I think') is peculiar in that it cannot be entertained without at the same time and for that very reason being true. It is not a necessary truth: it might have been false. Nevertheless I know for certain that it is true. I know this, since, even if I were to doubt that I think, then my very doubt would confirm that I do think. In other words, the proposition 'I think' is self-verifying: the mere possibility of thinking it establishes its truth. It is therefore absurd to doubt it." Scruton, A Short History of Modern Philosophy, p.31.
Another possibility is that the Cogito is an inference. When it is formulated as 'I think, therefore I am' it sounds very much like an inference. There appears to be a premise ('I think') and a conclusion ('I exist'). If you think of the Cogito like this (ie as an argument) you will be tempted to think there must be answer to the question: 'In virtue of what logical principle is this argument valid?' But if you allow this question to be raised you will find it difficult to suggest an answer which is as certain as the Cogito itself ...
Descartes says that 'I think therefore I exist' (whatever it is, argument or claim or 'intuition' or whatever we think it is) is seen to be certainly true by 'the natural light of reason'. Here is Descartes committing himself to the idea that our reason can tell us things that are true about the world we live in. (I mean, he doesn't think of the truth of 'I think' as being a matter of the meaning of words - he doesn't think of it as an 'analytic' truth.) This marks him out as a 'rationalist'. A rationalist does not necessarily think that reason is the only source of knowledge, just that it is one source. A rationalist thinks that we have, besides our senses, another window onto reality, our reason.
Descartes expresses this view that it is our reason which tells us that 'I think therefore I exist' is certainly true by saying that the Cogito is valid in virtue of the principle that whatever is absolutely clear and distinct as an idea is certain.
It is our reason that tells us that an idea is 'clear and distinct'.
A great deal for Descartes hangs on how this question of the source of the Cogito's apparent certainty. He says: I have reached the conclusion that there is one thing I can be absolutely certain about, that I, as a thinking thing, exist. What principle have I invoked in arriving at this conclusion? That whatever appears to my reason as 'clear and distinct' is certainly true.
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Prompt: What do you think of this? |
The next step of Descartes' argument is pretty breathtaking.
Having derived from the Cogito the principle that whatever is absolutely clear and distinct as an idea is certain, he goes on the say: but the idea of God is as clear and distinct as the Cogito.
Therefore I can be as certain that God exists as I can that I myself exist.
'... I considered in general what is required of a proposition in order for it to be true and certain; for since I had just found one that I knew to be such, I thought that I ought also to know what this certainty consists in. I observed that there is nothing at all in the proposition, ' I am thinking, therefore I exist' to assure me that I am speaking the truth, except that I see very clearly that in order to think it is necessary to exist. So I decided that I could take it as a general rule that the things we conceive very clearly and very distinctly are all true; only there is some difficulty in recognising which are the things that we distinctly conceive.' Discourse, Part IV, Cottingham p. 36. e-text
However, you can also discern two quite distinct arguments for the existence of God:
The first argument is this:
'Since, then, we have within us the idea of God, or a supreme being, we may rightly enquire into the cause of our possession of this idea. Now we find in the idea such immeasurable greatness that we are quite certain that it could have been placed in us only by something which truly possesses the sum of all perfections, that is, by a God who truly exists.' Descartes, Principles; Cottingham, Descartes - Selected Philosophical Writings, Cambridge, 1988, CUP, p.166. e-text
A longer formulation and treatment is to be found in Meditation 3.
One response was to say that we don't have the idea of God. (Hobbes, Gassendi).
Hobbes said we couldn't form an idea of God because we couldn't form an image of God. Descartes said an idea is not an image.
Gassendi said that a finite intellect was incapable of conceiving of the infinite.
Descartes addresses this. He thinks he can demonstrate that we do have an idea of God.
Kenny offers a reconstruction of his argument.
It uses the difficult notion of a 'perfection'.
What can one say of his use of 'perfection'?
A perfection is a feature of a thing, but it is a feature which contributes to the thing's being a perfect thing of its kind.
Here is Kenny's interpretation of Descartes' argument for the conclusion that we do have the idea of God:
Having established that we have the idea of God, Descartes then argues that it can only have been put in our minds by God.
This is a type of cosmological argument. It points to a feature of the world and argues that this feature needs a causal explanation which can only be supplied by the invocation of God.
There are a number of ways of putting it. Descartes himself often asserts simply that 'nothing comes from nothing' - ex nihilo nihil fit .
Or:
A thing can only come from something as or more perfect than it is itself.
Or (is this different?):
'There must be at least as much reality in the efficient and total cause as in its effect.'
The other proof of the existence of God offered by Descartes is an ontological argument:
Colin McGinn reports finding the ontological argument inspirational in his engaging The making of a Philosopher, London, 2003 ed., Scribner, p. 8ff. McGee admits he was in an unheated bedroom in Blackpool at the time however.
'I saw quite clearly that, assuming a triangle, its three angles must be equal to two right angles; but for all that I saw nothing that would assure me that there was any triangle in the real world. On the other hand, going back to my examination of my idea of a perfect being, I found that this included the existence of such a being; In the same way as the idea of a triangle includes the equality of its three angles to two right angles, or the idea of a sphere includes the equidistance of all parts (of its surface) from the centre; or indeed in an even more evident way. Consequently it is at least as certain that God, the perfect being in question, is or exists, as any proof in geometry can be.'
Descartes, Discourse Part IV; Cottingham, Descartes - Selected Philosophical Writings, Cambridge, 1988, CUP, p.38. (But I get the translation here from Kenny, p.146.)
"By studying the idea of God, Descartes comes to the conclusion that 'he cannot be a deceiver, since the light of nature teaches us that fraud and deception necessarily proceed from some defect.' From this principle he later proves the validity of mathematics and the external world."
Kenny, p.145.
| A.That at least two people exist - you and the person you just heard | B.That you exist | ||
| C.That someone within earshot exists | D. That you are not 100% deaf | ||
| A. I am speaking | B. I am writing | ||
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C. I am a human being |
D. I am not sure | ||
| 1. Logic | B.Extensive observation | ||
| C. Universal assent | D. Adherence to a valid principle | ||
| A. Everyone has the idea of a father, and the idea of God is just an extrapolation of that |
B. It can be proved mathematically that we have the idea of God |
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| C. You don't have to have the idea of God in order to accept that He exists | D. Anyone who denies that he has the idea of God is demonstrably wrong | Ask a friend | |
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Last revised 12:01:05
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