Descartes vs AI
Posted on 6th May 2009 at 10:18 by Clive Webster with 22 comments
I'm not sure why I got into Descartes - most of modern philosophy is pedantic and dry to the point of making the reader narcoleptic - but Descartes was an interesting fellow. He was notoriously lazy, never getting up before midday, and spent most of the waking day in a dressing gown beside the fire reading. When he took a job to teach Queen Christina of Sweden he was forced to get up early to start his lessons however, and famously died of pneumonia due to the early starts.
The really interesting thing about Descartes (and the reason why I'm writing this) is because he would probably have believed that AI is impossible and that therefore anyone researching it was wasting their time.
The reason for this is Descartes' two fundamental beliefs about science and the human mind. He didn't just say, 'I think therefore I am' y'know...
Descartes stated that before one should invest time in scientific research, one should ascertain whether the subject being researched is possible. 'Possible' in the realms of philosophy is a tricky subject, but let's settle on defining it as 'logically possible' for now (otherwise we'll get into a discussion of Kripke's excellent Naming and Necessity, and that's too long a discussion for a blog).
Essentially, by saying that you should investigate the possibility of something being true before trying to prove whether it's true or not, Descartes is saying you must do your philosophy before you do your science.
He'd then move onto to his theory of the human mind to show that artificial intelligence is impossible. Descartes staunchly held the view that the human mind was a separate entity to the human body, a theory which is called Dualism.
The argument for any kind of Dualism is a complex one - to argue that a non-physical mind can control a physical body, and be affected by that physical body is far from a naive opinion.
Descartes' 17th Century Christian beliefs were an influence on his theory of Dualism, but it was mainly his pursuit of items of undeniable knowledge that resulted in Cartesian Dualism. To find such nuggets of incontrovertible truth he tried to doubt the truth of absolutely everything (Cartesian Doubt).
However, he found that he couldn't doubt the existence of himself as a thinking entity: as soon as you have a thought, you can't doubt that the existence of the thing having that thought - 'I think therefore I am.'
It's much easier to doubt the physical world, however. All our mental experiences are merely electrical signals delivered to the brain via nerves; if someone were to replicate these signals with a living brain sitting in a vat on some mad scientist's shelf, there would be no experiential difference.
That you could doubt the existence of your body but not your mind, Descartes said, meant that the mind and the body were (or at least, could be) distinct. It also gave the mind a certain superiority over the body and the base instincts of its 'animal spirits'.
Descartes never really provided a decent argument as to why such a superior entity as a mind would ever want to be attached to the human body, but his argument did mean that he believed anything purely physical couldn't think. Therefore, surely there can be no AI and so all these people playing around with robots are wasting their time. Descartes also believed that animals not only had no mind but were incapable of feeling pain, leading to live dissections of many animals. I'm guessing he wasn't a vegetarian.
Current-day philosophers have a very different view of the human mind however, which supports the work of the AI pioneers. The theory is Materialism and merely states that the human mind is merely a nice way of referring to a load of chemical and electrical happenings in the human brain, and no more. According to this theory, AI is eminently possible.
Materialism poses some serious questions for most theologians (or should that be the other way round?) and doesn't seem to capture the variation and wonder of the human mind. It seems rather a sad theory of mind compared to Descartes' fantastical ideas, doesn't it?