On Descartes' Scepticism

The following post is an edited comment to a blog entry in the PH1101E Reason and Persuasion blog. The original blog entry discusses a few general ideas about René Descartes' Meditations I. Comments on the blog is part of the assessment for the module.

I shall attempt to discuss the question

Is Decartes' skepticism interesting?

To me, his scepticism is certainly interesting. Considering the "what if I'm dreaming" part, it is indeed a question worthy of pursuit even if it may not ultimately fetch an answer. This "what if I'm dreaming" is just like the "brain in a vat" situation, or now also "the Matrix" situation. It satisfies man's desire to know more about himself and the world. Such scepticism challenges established notions and ideas most people have assumed to be true, and only by knowing that they may be flawed can we proceed on to find the "truth". (After all, if humans have never asked this "what if I'm dreaming" question, we would not have the movie "The Matrix"!)

Yet perhaps the level of scepticism Decartes is applying to his analysis may be too extreme. After all, not all knowledge can be attainable and not every question can be answered. For example, the simple question of "does God exist?" is probably one which cannot be proven concretely to be true or false. If one seeks to find answers in such a manner, throwing out an idea once there is something doubtful about it, then he or she may very well be heading towards nihilism.

A more important question to ask, then, would be "is Decartes' skepticism useful?"

To that, my answer would be a "yes". At least, for myself being a scientist (or scientist-in-training), the value of scepticism can never be underrated. Throughout scientific history, old ideas are being overthrown by new ones - I would go as far as to say that discoveries in science is about overthrowing old ideas - and if scientists never strongly and unceasingly doubted established ideas, these new discoveries would never surface. Physicist Richard Feynman puts it most clearly when he said,

"Doubt is clearly a value in the sciences. Whether it is in other fields is an open question and an uncertain matter. I expect in the next lectures to discuss that very point and to try to demonstrate that it is important to doubt and that doubt is not a fearful thing, but a thing of very great value."
- "The Meaning of It All", pg. 28

Yet it must be noted that if one bears complete scepticism, throwing out everything that has a bit of uncertainty, then he or she will end up throwing the whole of science out of the window. There has to be a measure of "acceptability" of an idea, and in science this is often described by "beyond reasonable doubt through experiments". So scepticism is only useful when applied moderately.

Feynman left the applicability of scepticism in other areas of knowledge unexplored (at least up till before this paragraph), but I think it is also quite clear that doubt is very useful in many other fields. For example, one needs to apply a fair amount of scepticism when reading a commentary or argument, and when analysing messages from politicians and biased opinions.

In conclusion, the ability to doubt is important, but there must be a limit to the amount of scepticism one has. Decartes' scepticism is certainly interesting and probably useful as long as he has a reasonable measure of when to stop doubting.