Must φ is felicitous only if φ is not known

In recent work (von Fintel & Gillies 2010, Matthewson 2015, Lassiter 2016, Mandelkern 2016), epistemic modals have been claimed to have felicity conditions that require the evidence for the prejacent to be indirect. In contrast, I argue that epistemic modals have felicity conditions that require that the prejacent is not known as claimed in Giannakidou & Mari 2016. New linguistic data is produced in support of this position. The proposed account is argued to explain the new evidence better than accounts that rely on indirectness. The evidence in favor of this account also militates in favor of a weak semantics for must φ . In light of these findings, future prospects are explored. In particular, I suggest that this proposal paves the way for the felicity conditions of epistemic must to be derived as a conversational implicature. Furthermore, I demonstrate that a purported counterexample to the proposal, must φ statements in the conclusions of deductions, is a problem for indirectness accounts as well, and I suggest a way forward. EARLY ACCESS