I read somewhere that what Descartes really said was, “I think, therefor I am French.” Or may be, “I think in French, therefore I am.” Ok, that was in a phrasebook called Wicked French. In reality, the phrase was originally written in Latin, I believe — Cogito Ergo Sum. It introduced us to the beautiful geeky word Ergo. But what does the statement really mean?
I always thought that it was a sort of obvious, simple statement — if you express your doubt, “Do I exist?”, all I have to do is to answer with another question, “Who is asking the question?” This would essentially prove that the doubter exists; or so I thought. But recently, I read a more formal argument regarding this statement, and I thought I would share it here. I guess it is, in fact, Descartes’s original argument.
The argument goes like this: our senses may deceive us. A good home theater system, for instance, would fool us into believing that there are commandos firing machine guns behind us. Avatar in 3D might convince us that we were on an alien planet. And, how do we really know that we are not in the Matrix? So let’s go through the philosophical exercise of doubting everything. Let’s say that this computer screen you are looking at is not really there — it’s just some neuronal firings in your brain, like when you are dreaming that you are in front of your computer screen, reading this article (or, more likely, not reading this article). In fact, let’s say there is no brain to begin with. Just a disembodied sensation that results in your perception of a computer screen.
How far can you take this doubting business? We can write off everything material, made of substance, because no substance has an existence other than as its properties in our perception. So our body (including the brain) could be an artefact of our perception. In fact, it really is only a cognitive construct like everything else we sense. But mental things, like thoughts and indeed doubts, cannot be doubted because they exist in and of themselves. So doubts cannot be doubted. I mean, they cannot be reduced to something simpler whose existence can be faked. The same goes for mind as well. And if the mind exists, the person exists. Ergo, if you think, you exist.
I guess this complicated argument is not much better than the simpler rebuttal. If you ask me whether you exist, I only need to rebut by asking, “Who is asking the question?” Perhaps the complex argument sounded better in French. In fact, calling this line of thinking Methodological Skepticism already makes it sound a lot better.