These are the Knowledge Principles:(Disquotational Principle) An utterance of “S knows that p” at time t is true iff at time t S knows-tenseless that p.
(Practical Environment Principle) S’s evidence concerning p is good enough for knowledge iff S’s evidence for p is good enough to make it epistemically rational for her to act on the assumption that p.
(Parity of Evidence Principle) If the evidence concerning p for S and T is the same, then S’s evidence is good enough for knowledge iff T’s evidence is good enough for knowledge.
The Knowledge Principles are inconsistent, given only the truism that different people can have different practical stakes. Take a Bank Case (DeRose 1992), in which Hanna and Leila each have the same rather good evidence that the bank is open Saturday, but acting on a mistaken belief would harm Hannah much more than Leila. Hannah is in a high-stakes context, Leila in a low-stakes context. The Practical Environment Principle, which entails that Leila knows that the bank is open and Hannah does not, here generates an inconsistency with the Parity of Evidence Principle, which entails that Leila knows if and only if Hannah does.
Two things strike me as really strange about this claim, even setting aside the question of whether these principles are plausibly constitutive of the meaning of 'knows'.