From his First Meditation, Descartes makes the rather gloomy conclusion that every single piece of knowledge must be doubted. As I will discuss below, he considers a number of arguments that cast doubt on his existing knowledge and eventually concludes that there is good reason to doubt everything. However, in the Second Meditation, he thinks more closely on the question, and decides there is one thing that he can be certain of: his own existence based on the fact that he is thinking (the famous ‘cogito’: ‘I think, I am’).
But how far does the Second Meditation go in refuting the position of ‘radical doubt’ so firmly established by the First Meditation? This post will argue that the Second Mediation does little to change the conclusion made from the First Meditation, and ‘radical doubt’ can still be maintained as Descartes’ primary position. If anything, the position of radical doubt can be strengthened as a result of the Second Meditation.
Starting with the First Mediation then, Descartes decides to go through a process of analysis whereby he subjects all his knowledge to a sceptical process of doubt. Rather than going through each piece of knowledge one-by-one – which of course would be an impossible job – Descartes contends that he only needs to look at the ‘foundations’ of knowledge. If he can find some reason to undermine the foundations, then the entire house comes crashing down.
Descartes then proceeds to raise a number of arguments that cast doubt on his knowledge. His first line of thought is that the primary source of our knowledge is the senses, and it is clear that the senses do deceive us on occasion. However, some sensory input cannot be doubted, such as the fact that you are sitting and writing at a piece of paper.
The next argument is that we may be dreaming, so cannot be certain that anything we experience right now isn’t part of a dream world. Although this is more persuasive than the sense argument – it is difficult to find any certain way to ‘prove’ that one is dreaming over being awake – Descartes realises that dreams still contain images from the real world that cannot be doubted, such as colours, geometry and mathematical knowledge.
Finally, Descartes considers that God may be deceiving us on the true nature of the world, and implanting all these false thoughts into his mind. At first Descartes is rather horrified by this thought, for God is the ‘ultimate in goodness’ and would never do anything to deceive. However, at the same time, it can’t be doubted that people are in fact deceived. So saying that God never deceives us cannot be accepted as a convincing argument.
Descartes seems to run out of arguments at this point and decides there is no knowledge that he can be certain of. Going forth, he must pretend that he is being controlled by a ‘malicious demon’ who is implants completely false beliefs into his head. This is the position of ‘radical doubt’, of being sceptical about every single piece of knowledge that one has. One could ask Descartes why he feels the need to doubt the existence of absolutely everything in such an ‘all or nothing’ manner. Nevertheless even if we fail to be convinced by ‘radical doubt’, we can still accept that it is one of the more extreme ways of viewing knowledge in general.
This then leads us to the Second Meditation. Descartes admits he is unsettled by the conclusions from the First Meditation, so decides to have another think. Surely there must be at least one piece of knowledge that he can be certain of? And Descartes believes he has found it: his own existence based on the fact that he is going through the process of doubt in the first place. Even if all his beliefs are false – and some malicious demon is feeding him all the information – he still cannot doubt the fact that he is having these sceptical thoughts. So this Descartes some cause for hope. He does not have to doubt everything.
However, the Second Mediation then returns to a more sceptical position. Descartes has just concluded that ‘I am, I think’, but who exactly is this ‘I’? Descartes contends that he has a body that appears to be feeding him sensory information. But why should he be so certain that these sensations are true? This leads him to adopt a position of dualism, whereby he perceives the mind as a separate entity from the body. While he can doubt the fact that his eyes are really seeing what they are seeing, he can’t doubt the fact that his mind is processing certain visually-related thoughts. So we can summarise the Second Mediation as Descartes attempt to prove one thing exists: his mental thought processes, as opposed to any bodily processes or sensations, which are just as doubtful as anything in the external world.
If Descartes can only be certain of his process of thinking, this doesn’t take us very far in rejecting the idea of ‘radical doubt’. You can still maintain a position that everything in the external world should be doubted – which includes any sensations registered by the body – while maintaining that your mind is the one certain source of knowledge. However, since the thoughts are always based on sensations – David Hume for instance said that all ideas were based on impressions – then what is left for the mind to know outside of sensory experience? This seems to be almost nothing at all. So rather than refuting the theories of the First Mediation, the Second Meditation only strengthens the position of ‘radical doubt’, and leaves us wondering if there are any thoughts in any mind that we can be absolutely certain of.