PY1002 Descartes Foundationalism and the Cogito

The fact that being awake and dreaming can be identical phenomenologically means

they should be treated as having the same epistemological or cognitive value.

After feeling the weight of the gaps of his education Descartes

took a gap year

God

The existence of an omni-benevolent God is no guarantee that we are not systematically mistaken in our beliefs, since such a God does exist and we are sometimes mistaken.

What are the 'principles on which all my former beliefs rested'?

'All that up to the present time I have accepted as most true and certain I have learned either from the senses or through the sense...' (Meditation 1)

Descartes realises that despite all his doubts he can be sure of one thing:

'But I was persuaded that there was nothing in all the world [...] was I not then likewise persuaded that I did not exist? Not at all; of a surety I myself did exist since I persuaded myself of something' (Meditation 2)

The 'cogito'

'I think therefore I am' (Principles of Philosophy I, VII) Also appears in Discourse on Method Part 4 and in Meditation 2

Descartes' project

'I thought it necessary to do the very opposite and reject as if absolutely false everything in which I could imagine the least doubt.' (Discourse on Method 4)

Rejecting all beliefs seems like it could be an endless task BUT

'Once the foundations of a building are undermined, anything built on them collapses of its own accord; so I will go straight for the basic principles on which all my former beliefs rested.' (Meditation 1)

Descartes questions the state of philosophical knowledge

'Philosophy had been pursued for many centuries by the best minds, and yet everything in it is still disputed and hence doubtful.'

Barrel of apples analogy

'Supposing he had a basket of apples and, fearing that some of them were rotten, wanted to take those out lest they might make the rest go wrong, how could he do that? Would he not first turn the whole of the apples out of the basket and look them over one by one, and then having selected those which he saw not to be rotten, place them again in the basket and leave out the others?' (Seventh set of objections and replies to the Meditations)

Hats and coats analogy

'Yet do I see any more than hats and coats which could conceal automatons? I judge that they are men. And so something which I thought I was seeing with my eyes is in fact grasped solely by the faculty of judgement which is in my mind.' (Meditation 2)

Senses can be deceiving

'it is sometimes proved to me that these senses are deceptive, and it wiser not to trust entirely to anything by which we have once been deceived.' (Meditation 1)

Descartes realised:

1. A lot of his beliefs were false 2. His other beliefs that were based on these false beliefs might also be false (foundationalist assumption) 3. If he wanted to achieve knowledge, he would have to reject all of his beliefs

Descartes born

1596

Descartes died

1650

Rationalist position

Important aspects of our knowledge are gained independently of our sense experience.

Evil Genius

Descartes imagines that the world is controlled by an Evil Genius who 'has employed his whole energies in deceiving [him]' (Meditation 1). This allows him to doubt everything.

Unlike the pre-Modern idea of taking knowledge on trust

Descartes wanted to identify beliefs in which he could be absolutely confident, since these beliefs would definitely be true

Gassendi's objection

Descartes' inference could just as easily have been derived from any of his other actions, did not need to be thought or doubting. 'whatever acts exists'

'Some years ago I was struck by the large number of falsehoods that I had accepted as true in my childhood [...]

I realised that it was necessary, once in the course of my live, to demolish everything completely and start again right from the foundations' (Meditation 1)

The Evil Genius doesn't throw doubt upon Descartes' existence because

If he is being deceived by the Evil Genius, he must exist as a being able to fall prey to deception.

I think therefore I am is not enough without intellect

It is only by connecting it to the idea that in order to think it is necessary to exist that it bears weight.

A posteriori knowledge

Knowledge gained through experience E.g. Bachelors are fat The earth orbits the sun

Epistemological foundationalism

Knowledge is like a building, and its existence depends on its foundations. If the foundations of our belief system are false then the whole 'building' that is our knowledge is in danger of collapsing.

A priori knowledge

Knowledge that can be gained independently of experience. E.g. Bachelors are unmarried 2+2=4

Descartes doubts Maths and self-evident beliefs because

People are sometimes mistaken in their beliefs, even when they are very certain of them and since people are sometimes mistaken, we cannot know that we are ever not mistaken.

Being awake & dreaming =

Phenomenologically identical: they appear to us the same

Ball of wax

Senses and imagination are unable to reveal a persisting object. It is the intellect that reveals there is a persisting object. 'the perception I have of it [the wax] is a case not of vision or touch or imagination - nor has it ever been, despite previous appearances - but of purely mental scrutiny.' (Meditation 2)

Mersenne's objection

Since you do not know what thinking is or existence is, 'how can you know that you are thinking or that you exist?'

Rationalism

Some knowledge is gained by intuition, some deduced from intuited premises, some is innate - we are born with it. Knowledge gained in these ways is a priori.

Descartes' reply to Gassendi

There is less certainty surrounding actions than surrounding thought. 'I may not for example, make the inference "I am walking, therefore I exist", except in so far as the awareness of walking is a thought. The inference is certain only if applied to this awareness, and not to the movement of the body which sometimes - in the case of dreams - is not occurring at all, despite the fact that I seem to myself to be walking.'

Descartes' reply to Mersenne

Thinking and existence are innate knowledge. We may sometimes confuse ourselves and think we don't have it if we get tangled up in words and their meanings. Even though someone may never have considered what thought or existence are, the mere fact they have noticed they are thinking means they are able to conclude they exist.

"there are never any sure signs by means of which

being awake can be distinguished from being asleep.'

He felt the experience of other cultures to be

beneficial

Descartes doubts not just sense-based beliefs, but

maths and self-evident beliefs too. 'how do I know that I am not deceived every time that I add two and three, or count the sides of a square, or judge of things yet simpler, if anything simpler can be imagined?' (Meditation 1)

If I can't rely on dreaming to tell me anything about how the world is (because it doesn't) then

neither can I rely on sensory experience to tell me anything about how the world is.