The work of René Descartes (1596-1650) played an important part in what historians used to call the ‘Scientific Revolution’. And that means he was involved in developing the way you think, and how you live your life. But our very familiarity with his way of thinking makes it hard for us to see just how Cartesian our attitudes still are.
Most people who have heard the name of Descartes tend to associate it either with the slogan ‘I think, therefore I am’ (which I’ll talk about tomorrow), or with Sceptical arguments. He argued that what you call reality may be nothing but a dream, and suggested an Evil Demon might be messing with your mind so that you go wrong even about things you’re most certain of. He used those arguments to try to show that we should never trust our senses, and that real knowledge can only be acquired if we turn away from them, and follow Reason.
People who have heard of this stuff tend to regard Descartes as either a hero or a fool. He seems to be the archetypal philosopher, producing clever but essentially pointless arguments for conclusions that no-one can ever believe, since whatever their theoretical position, none of the people who discuss these ideas with such skill is ever actually going to live their lives on the basis that we can’t put any trust in what we see around us.
But actually that is not what Descartes was about at all. He was working to a very serious practical and political agenda, trying to popularise and defend a set of radical ideas. Those ideas have since become so engrained in our way of seeing the world that we have quite lost sight of them, and of where they came from.
What we have to remember is that the Scientific Revolution was all about getting people to deny their senses. If you want to persuade someone that the solid Earth they stand on is actually flying through space, the first thing you have to do is to find some way of overcoming the fact that it doesn’t feel like that. If you want them to believe that there are uncountably many tiny creatures living in the clearest water, that an empty box is crammed full of invisible matter, and that if you want to see clearly you should try peering with one eye through two bits of glass in a tube, then you need some way of getting them not to base their conclusions on the way things look, but to try to work out what’s really going on behind it.
The simple fact is that if you think – as most of us do – that the world we see around us is a result of the interactions of tiny, invisible particles, then you are in effect a Cartesian, a follower of Descartes. You are a Cartesian because you think that although our senses are essential for us to know anything about the world, nevertheless in order for us to understand that world we have to look beyond what we experience, to a reality which none of us has ever seen, which few of us can understand, and which can only really be described in the arcane and often contradictory language of quantum mechanics. That world can be discovered only by what Descartes called ‘reason’, and what we have since come to call ‘empirical’ science.
Interestingly, in addition to the senses Descartes’ other main targets were tradition and authority. He thought people shouldn’t believe things just because some authority had said them, or because they were brought up that way and have never questioned them, but should think them out for themselves. It is ironic that most of us now accept his metaphysical picture – that of a deeper level behind the sensory appearances – for just the reasons he so despised.