Nyaya externalism, a form of reliabilism, answers Nagarjuna's skeptical attack with a coherentist model of the sources of knowledge. @PhiloofAlexandria
What is belief? What is the relationship between belief and consciousness? There is belief as a linguistic term and there is belief as an inference of experience and culture. Belief as a linguistic term can be argued using epistemological categories. Belief as an inference is the quantum of consciousness. As an epistemological argument belief can break down into an infinite regress. Just as in Zeno's paradox of halfway there means never there, however, the regress is flawed. Flawed because the principle or rule cannot admit it's limit. The limit that one does not need to count to infinity to realize that because the measure is actually getting closer that means it will eventually get there. Nagarjuna, like Zeno, is so stuck in his linguistic rule he fails to admit that because the rule allows for getting close it can get there. Zeno and Nagarjuna want to indulge in infinity legality as opposed to infinity practicality. They can never see the forest because they're always counting individual trees. They refuse to admit that a certain number of trees actually makes for a forest. Even a blind man can admit he's not bouncing into the same tree every time. They both participate in a willful blindness. They prefer to stick to the definition of the rule rather than to admit it's consequence. They enjoy telling you what's going on than telling you what's going to happen. A rule is not an inference. An inference joins things that are not "necessarily" connected. A rule is a definition, it makes distinctions between things, separating things which are not "necessarily" separate.
I'll take up intersubjective agreement (cool phrase btw). If I'm very good at naming things, and another person is...maybe not so good, then after a time our general pictures of the world will differ to some degree. But it is possible that we both are reliable sources of knowledge, ex. there are various teachers who are not identical. So, consider each individual as a world. There are certainly worlds where every time you walk into a room it's different. Excluding those, and taking only the worlds with a modicum of consistency, we might get the set of all reliable sources. Now, why should there be an objective type of knowledge outside this set? Whence this idea of absolute truth? I think people want to know "the way things are," but this is an illusion, because both people and the world (the real world) are in continuuous motion. So...I guess that's an anthropic view of epistemology. People know things.
The classic book that treats metaphysics and logic as quite closely related is Bertrand Russell's "The problems of philosophy". It's short, well-written, and accessible, and you can find a free PDF of it online for sure.
