"I think, therefore I am" only implies that the speaker exists. It says nothing about the speaker's mental state.
Consider the philosophical riddle: How do you know that the world did not simply come into being last Thursday? You have memories from before then, but there is nothing that proves that these memories were not, like the history of the world, likewise fabricated.
For that matter, Descartes also arrived at another problem: The certainty of one's surroundings. Cogito, ergo sum. I think, therefore I am. But I do not know that you are. You could be a construct talking to me. I could be a figment of your imagination.
From a philosophical standpoint, 'truth' is difficult to establish.
no subject
Consider the philosophical riddle: How do you know that the world did not simply come into being last Thursday? You have memories from before then, but there is nothing that proves that these memories were not, like the history of the world, likewise fabricated.
For that matter, Descartes also arrived at another problem: The certainty of one's surroundings. Cogito, ergo sum. I think, therefore I am. But I do not know that you are. You could be a construct talking to me. I could be a figment of your imagination.
From a philosophical standpoint, 'truth' is difficult to establish.