Of course, whatever I have so far accepted as supremely true I have learned either from the senses or through the senses. But I have occasionally caught the senses deceiving me, and it's prudent never completely to trust those who have cheated us even once. But, my senses may deceive me about what is small or far away, there may still be other things that I take in by the senses but that I cannot possibly doubt---like that I am here, sitting before the fire, wearing a dressing gown, touching this paper. And on what grounds might I deny that my hands and other parts of my body exists?---unless perhaps I liken myself to madmen whose brains are so rattled by the persistent vapors of melancholy that they are sure that they are kings when in fact they are paupers, or that they wear purple robes when in fact they're naked, or that their heads are clay, or that they are gourds, or made of glass.

Could I get some perspective or perception on these questions accoeding to your experiences?

1. Think of a time when your senses deceived you. Describe what you thought you saw, heard, or felt, and then e you in the past?

Explain how you came to realize that your initial perception was incorrect.

2. Do you think it is reasonable to rely on your senses considering that they have fooled you in the past?

3. Consider Descartes' comparison of himself to a madman---how do you know that what you experience is any more real than what a so-called madman experiences as real? Who is to say which experience is valid, and on what grounds?

4. How does reason play into the evaluation of what is real?