Forcing epistemology is a trendy way of defeating the skeptics who since the days of old have cited prima facie error possibilities as some of the most devastating arguments against claims to knowledge. The idea of forcing is to delimit the set of possibilities over which the inquiring agent has to succeed: If the agent can succeed over the relevant possibility set, then the agent may still be said to have knowledge even if he commits many errors, even grave ones, in other but irrelevant possibilities.

Contemporary epistemological studies are roughly either carried out:

1. in a mainstream or informal way, using largely conceptual analyses and concentrating on sometimes folksy and sometimes exorbitantly speculative examples or counterexamples, or (2) in a formal way, by applying a variety of tools and methods from logic, computability theory or probability theory to the theory of knowledge. The two traditions have unfortunately proceeded largely in isolation from one another.

Many contemporary mainstream and formal epistemologies pay homage to the forcing strategy. The aim of this book is to demonstrate systematically that the two traditions have much in common, both epistemologically and methodologically. If they could be brought closer together, not only might they significantly benefit from one another, the way could be paved for a new unifying program in ‘plethoric’ epistemology.