How does Descartes argue for I am I exist
... The use of knowledge can answer the question “Do we exist?” For all my life, I believed we existed because why should I think otherwise? Everything I have learned or experience has been through the senses. I know fire is hot from its touch. I know the difference between chocolate and lemons from their taste. I know what a bird looks like from viewing them with my own two eyes. But why should I trust my senses? I realize my senses deceive me, suggesting that I may not exist. If I cannot trust my senses, why should I trust other ideas that I accepted as true when they may in fact be falsehoods. Do I not know people cannot be the size of ants?