The first thing to understand is that Descartes didn’t just come up with this in a vacuum. He was trying to answer a specific question. Suppose that some sort of evil demon was feeding our minds false perceptions of reality -fake sights, sounds, and all the other senses- such that nothing we experience is actually *real*. In modern terms we ask ourselves this same question using The Matrix instead of a demon, but the principles are the same. In the face of this possibility, how can we really be sure that anything we perceive is real? How can we even be sure that we ourselves are real?
Descartes asserts that even if the demon’s tricks are so crafty that we cannot be sure of anything else, we can be sure of our own existence. The proof is in the fact that we have the capacity to doubt what the demon is showing us: it might be able to control everything we see and hear and touch, but even so, it cannot control our thoughts completely: the simple act of wondering about our reality, rather than simply accepting the demon’s illusions as fact, proves that our thoughts are not under the demon’s control, even indirectly. Our thoughts are real, even if nothing else is. And since our thoughts are real, the beings that think them -us- must also be. We exist, even if the things our brain shows us do not.
Latest Answers