Epistemic Closure, Dogmatism, Scepticism, Fallibilism

This chapter explores an epistemic reading of the two-place TSIM operators, in which they are interpreted as capturing the notion of Knowability Relative to Information (KRI), Kφψ: given total (empirical) information φ, one is in a position to know that ψ. In the KRI setting, the variable strictness of two-place TSIMs makes them suitable to model the non-monotonicity of knowledge acquisition (sometimes one can know less after getting more, even truthful, information) while allowing knowledge to be intrinsically stable. Their topic-sensitivity allows them to invalidate controversial forms of epistemic closure (closure of the relevant knowledge state under full logical consequence) while validating less controversial ones. Unlike the standard Hintikkan modal framework for epistemic logic, the KRI framework models insights friendly to epistemic fallibilism: the view that one can sometimes know that φ even if one is not in a position to rule out all possible scenarios in which φ fails. It also accommodates plausible approaches to the Kripke-Harman dogmatism paradox (the paradox whereby knowing agents seem to be immune to rational persuasion via information bringing in new evidence), which bear on non-monotonicity or on topic-sensitivity.