For years i had been bothered about how to more precisely formulate my ideas about fallibilism and make them consistent with the existence of noncontingent propositions. The question was: if some propositions are necessarily true, how can it be possible to be wrong about them? Since they are necessarily true, it is impossible for them to be false. But still, there was some sense in which it was possible to be wrong about such things. History of full of examples of noncontingent propositions that people were wrong about (like squaring the circle, naive set theory).
Then i read IEP’s article on falliblism and that makes things clear. Yay! Maybe now i can convince my math friends that they can be wrong about their proofs and simple math truths like 2+2=4.