In order to create an accurate model of psychology, which is needed to show the beliefs are wrong, you need to accept the very axioms I'm disagreeing with. You also need to accept them in order to show that not accepting them is a bad idea.
I don't see any way to justify anything that isn't either based on unfounded premises or circular reasoning. After all, I can respond to any argument, no matter how convincing, and say, "Everything you said makes sense, but I have no reason to believe my reasoning's trustworthy, so I'll ignore what you say." My question really does seem to have no answer.
I question how important justifying the axioms is, though. Even though I don't believe any of the axioms are justified, I'm still acting as if I did believe them.
You keep on using the word "justified". I don't think you realize that when discussing axioms, this just plain doesn't make sense. Axioms are, by definition, unjustifiable. Requesting justification for a set of axioms makes about as much sense as asking what the color of the number 3 is. It just doesn't work that way.
Standard methods of inferring knowledge about the world are based off premises that I don’t know the justifications for. Any justification (or a link to an article or book with one) for why these premises are true or should be assumed to be true would be appreciated.
Here are the premises:
“One has knowledge of one’s own percepts.” Percepts are often given epistemic privileges, meaning that they need no justification to be known, but I see no justification for giving them epistemic privileges. It seems like the dark side of epistemology to me.
“One’s reasoning is trustworthy.” If one’s reasoning is untrustworthy, then one’s evaluation of the trustworthiness of one’s reasoning can’t be trusted, so I don’t see how one could determine if one’s reasoning is correct. Why should one even consider one’s reasoning is correct to begin with? It seems like privileging the hypothesis, as there are many different ways one’s mind could work, and presumably only a very small proportion of possible minds would be remotely valid reasoners.
“One’s memories are true.” Though one’s memories of how the world works gives a consistent explanation of why one is perceiving one’s current percepts, a perhaps simpler explanation is that the percepts one are currently experiencing are the only percepts one has ever experienced, and one’s memories are false. This hypothesis is still simple, as one only needs to have a very small number of memories, as one can only think of a small number of memories at any one time, and the memory of having other memories could be false as well.