“I think therefore I am” is a logical proof of my own existence, and as such, I assign a probability of 1 to the proposition: “I exist”.
I’m not at all sure it’s any such thing. It depends a little on how broadly you’re prepared to construe “my own existence”.
You aren’t really entitled to say “I think”. You know that some thought is happening, but you don’t really know that what’s having that thought is the right sort of thing to be labelled “I” because that word carries a lot of baggage (e.g., the assumption of persistence through time) that you aren’t entitled to when all you have is the knowledge that some thinking is going on. So, for instance, if you go on—as Descartes does—to draw further inferences involving “I” from “I exist”, and if you assume at different times that you’re referring to the same “I”, then you are cheating.
Also I mentioned that even if you actually have a logical proof of something, you cannot assign a probability of 1 to the conclusion, because you might have made a mistake in the argument. You are pointing out some ways that might have happened here. Even if it did not, no one can reasonably assign a probability of 1 to the claim that they did not make such a mistake, and hence to the conclusion.
I’m not at all sure it’s any such thing. It depends a little on how broadly you’re prepared to construe “my own existence”.
You aren’t really entitled to say “I think”. You know that some thought is happening, but you don’t really know that what’s having that thought is the right sort of thing to be labelled “I” because that word carries a lot of baggage (e.g., the assumption of persistence through time) that you aren’t entitled to when all you have is the knowledge that some thinking is going on. So, for instance, if you go on—as Descartes does—to draw further inferences involving “I” from “I exist”, and if you assume at different times that you’re referring to the same “I”, then you are cheating.
For more about this stuff, see the Stanford Encyclopedia of Philosophy.
Also I mentioned that even if you actually have a logical proof of something, you cannot assign a probability of 1 to the conclusion, because you might have made a mistake in the argument. You are pointing out some ways that might have happened here. Even if it did not, no one can reasonably assign a probability of 1 to the claim that they did not make such a mistake, and hence to the conclusion.