Descartes says that we can be deceived by our senses. For instance, I say I see people crossing the streets, but I only see coats and hats, Descartes reminds us. What do you think about this? When can we claim we have knowledge of something? What is the difference between knowing (or understanding) and believing? What is your interpretation of the piece of wax illustration in Meditation Two? What is Descartes trying to prove by that illustration?