 But these principles seem false. You don’t know all the logical and mathematical truths, and there are truths which follow from what you know which you don’t know. (You might be indifferent to those truths; you might even disbelieve them.) This is the problem of logical omniscience (see  epistemic logic  again). There is a rich literature on the problem (Alechina et al. 2004, Duc 1997, Hintikka 1975, Jago 2014a,b, Rantala 1982a), including some who defend these seemingly false principles (Stalnaker 1991, 1999).