Descartes Discussion Points 1
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Descartes Discussion Points 1. Foundations (p.95) Descartes believes that real knowledge is only possible if it is built on fixed foundations, which he compares to a fulcrum needed for a huge lever. Nowadays the search for foundations is challenged by those who believe justification is either external (e.g. reliabilism) or is internal coherence. Neurath's Boat, which has no anchor but stays afloat because its planks fit together nicely, is the alternative model. Most foundationalists rely on basic sense experience, so Descartes is unusual in looking for a rational foundation. Maybe any search for rational foundations is doomed to end in solipsism. 2. Sceptical method (95) As a way of discovering totally certain foundations, Descartes invents a technique of ruthless doubt. If there is any doubt, a belief must be rejected. Maybe he doesn't distinguish enough between scepticism as a method and as a doctrine. It is a good method, which goes back to Socrates, and is the basis of modern science as well as philosophy. As a doctrine it is probably too demanding, and he should have relaxed a bit once he found that none of his beliefs could be fully justified. The doctrine demands total certainty, and this may be beyond human beings (or even a logical impossibility for God!). 3. Senses deceiving us (96) His first sceptical argument is that if senses have once deceived you, that proves they are not reliable, so they must be rejected. (This deception could be either uncertain information from the world, or false information generated by the senses, or a misinterpretation of what is experienced.) It may be correct that we should be cautious about sense experience (as illusions repeatedly prove), but it is not clear what the argument proves. Surely we should be cautious about senses before they even deceive us once? And if they deceive you once, what should you conclude? Don't trust your ears because your eyes deceived you? Don't trust your senses when looking at distant objects? Don't trust your senses if mine have deceived me ? A sceptic won't even be sure that his senses have deceived him. 4. Dreams (96) He suggests that rejecting sense experience is madness, but then realises that we believe mad experiences every day, when we dream. Near the end (p.168) he decides that we are not dreaming, because we cannot connect the parts of dreams together coherently. His rejection of dreams near the end seems optimistic, based on the demon being severely limited by the existence of a non- deceiving god. He needs some concept like a 'super-dream' to explain why our waking lives are so vivid and consistent. The truth is we can never escape the dream argument; if we 'woke up' now, it might just be into another level of dreaming. 5. Ultimate reality (97) Descartes’ investigations are aiming at establishing some ultimate reality (perhaps the physical world) which is beyond doubt. His whole aim, in the first meditation, may be misconceived. Even by the end of the book he isn't totally certain about any features of reality, because he admits that we make some errors. He thinks that if we agree that physical objects are there then most of our problems are solved, but there remain questions about secondary qualities, quantum physics etc. 6. Uncertainty of maths (98-9) At first he thinks that maths may be something which is totally certain, but then realises that some powerful force could delude him about maths, and make him foolishly over-confident. If pure luck has created him, then maths is even less reliable. It is arguable that simple arithmetic is more self-evident to us than any arguments about powerful forces or the luck of nature. If we can't get the right answer to 2+3, should we waste our time trying to reason about reality? The theory of evolution offers an account of nature which might produce reliable maths (as a way of thinking that results in survival). If God could deceive us about maths, presumably the demon could deceive us about the Ontological Argument. 7. Mental Interference (98, 100) The possibility of a powerful force interfering with his mind is one of his major sceptical arguments. At first he thinks God might do this, but then thinks an Evil Demon would have a better motivation. We might suggest an evil scientist, or ‘The Matrix’. This is argument is also hard to deny. Every thought that appears in my mind could be a projection by aliens or a hypnotist. Descartes eventually says that something is self-evident even if my mind is a receiving station (because it is clear and distinct), but we could take that further and say that arithmetic is also self-evident, and even that consistent sense experience must self- evidently be accepted. 8. Memory (102) He realises that his memory might be unreliable, so even if he did find the truth, he might not be able to hang on to it. He is probably not sceptical enough about memory, and he underestimates its importance. Bertrand Russell said the universe might have been created five minutes ago, in which case most of our memories are fiction. If he can't trust his memory he can't accept the Ontological Argument, because he must hold all the steps of the argument simultaneously in his mind. 9. Solipsism (103) The realisation that he himself might be creating a delusion that the world exists (instead of an outside force causing it) implies the possibility that nothing exists at all except his own mind – a view which is now known as ‘solipsism’. The horrible logic of solipsism is hard to escape. Descartes uses the Ontological Argument to prove that something exists outside his own mind. The best known modern attempt is Wittgenstein's Private Language argument, which claims that a solitary language is a logical impossibility, because a rule-following language has to be a community activity. Empiricists have less trouble with solipsism, though Berkeley thought existence was nothing but perception, which seems to create a mental prison of sense experiences. Solipsism may be a logical possibility, but it hardly looks like the best explanation of our experiences. 10. The Cogito (103) He realises that the proposition “I exist” has to be true whenever he is thinking. Even if all his thoughts are wrong, he must exist to be wrong. This is true only when he is actually thinking, and it is then a necessary truth (which couldn’t be false). The argument does not seem to be an abduction from evidence, or a deduction following logical steps, but a claim that a truth is self-evident. Since the alternative seems to be that nothing exists, Descartes obviously has a point. If thoughts could exist without a thinker (and Plato's theory of Forms encourages this possibility) then the argument would fail, but it would then be hard to see what connects sequences of thought. We could suggest that he has pointed out an obvious presupposition of all our thinking and language, and that it is just a dull tautology, but he could fairly reply that the idea that we must exist is hardly an arbitrary idea; it is a totally inescapable idea, and therefore very significant. We could say that he is over-optimistic about the stability of the "I" he has proved (the Cartesian Ego), and on p.127 he himself recognises that his self could be fragmentary, especially if his thoughts are fragmentary. Hume's 'bundle' theory of the self is of a fluctuating thing which couldn't form the basis for Descartes' philosophy. Indeed, it is hard to see how the addition of "I" to his observation that there are thoughts actually explains anything, so Ockham's Razor might suggest that we leave it out. However, if his Cogito does no more than show the limits of possible scepticism, that would make it an important idea. 11. A Thinking Thing (105) Once he is sure he exists (when thinking), he wonders what he is. He rejects Aristotle’s ‘rational animal’, and decides he is only the minimum required for thinking, which he calls a ‘thinking thing’ (res cogitans). His idea of his self is extremely narrow and lacking in individuality, and there seems to be no evidence for this 'thing' apart from the thinking. However, it is a good commitment for a rationalist to make, because it means he can trust the existence and stability of his understanding, which is the basis of all his other ideas. His belief in dualism seems an inevitable next step. 12. Imagination (106) Once he is certain of himself as a thinking thing, he wants to expand his understanding to the external world. He considers whether imagination might provide the necessary bridge, but realises that is no more reliable than dreams. Later (150) he uses the chiliagon example to prove that imagination is far less important than his understanding. He seriously underestimates the importance of imagination. It may not link him to reality, and he may be right that we can understand things we can't imagine (God? infinity?), but imagination is surely an essential and integral part of our ability to reason and understand. Doesn't he use his imagination when he is deciding that the molten wax is still wax? 13. Phenomenalism (107) As he realises the difficulty of finding a bridge from his mind to the external world, he begins to wonder whether he can only ever be certain of his experiences, and can never say for sure what the experiences are of.