There is no "why". If there was, then the assumptions wouldn't be called "assumptions". If you want to have a basis for believing anything, you have start from your foundations and build up. If those foundations are supported, then by definition they are not foundations, and the "real" foundations must necessarily be further down the chain. Your only choice is to pick suitable axioms on which to base your epistemology or to become trapped in a cycle of infinite regression, moving further and further down the chain of implications to try and find where it stops, which in practice means you'll sit there and think forever, becoming like unto a rock.
The chain won't stop. Not unless you artificially terminate it.
If there is no why, is any set of axioms better than any other? Could one be just as justified believing that, say, what actually happened is the opposite of what one's memories say?
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.