Whereas metaphysics studies reality, epistemology studies knowledge, rationality, and other forms of cognitive access to reality. This is a concern because of skeptical worries about how error-prone we human beings can be. Epistemology debates what knowledge and rationality are, and whether having them requires evidence or at least good reasons. It asks what evidence is to begin with. It also explores knowledge of persons and knowledge of how to do things, as well as other aims of inquiry, such as understanding, which involves grasping explanations of how things may fit together systemically. Social epistemology is a sub-discipline that concerns knowledge (or more broadly cognitive access) in social contexts. For example, it asks how we share knowledge with other people by testimony, whether it is rational to keep our own beliefs in the face of widespread disagreement, how digitalization and social media both facilitate and endanger knowledge, and (overlapping with feminist and critical philosophy) how power dynamics create inequalities and injustice in gaining or sharing knowledge. 

Religions typically come with belief systems or “maps of reality”; these are the focus of the epistemology of religion. A big question is whether faith in them is or can be rational. Important related questions include how to distinguish between rational religious faith and fundamentalism or conspiratorial thinking, and how and whether religious belief fits with contemporary science. Other questions concern scriptures, prophecies, or personal religious experiences – what sort of evidence if any do these provide about a putative divine reality? Additional sources of belief are religious authorities, but religious authority can be abused, and terms like “heresy” deployed to stigmatize nonconformists. Another key question in the epistemology of religion has been whether and how belief in God can be rational in light of the evidence provided by horrendous suffering and evil in the world.