 The earliest version of the proof was conveyed to Fitch by an anonymous referee in 1945. In 2005 we discovered that Alonzo Church was that referee (Salerno 2009b). His reports are published in their entirety in Church (2009). Fitch apparently did not take the result to be paradoxical. He published the proof in 1963 to avert a kind of “conditional fallacy” that threatened his informed-desire analysis of value. The analysis roughly says: \(x\) is valuable to \(s\) just in case there is a truth \(p\) such that were \(s\) to known \(p\) then she would desire \(x\). The existence of unknowable truths ultimately explains why he restricts the propositional variables to knowable propositions. For an unknowable truth provides for an impossible antecedent in Fitch’s counterfactual, and ultimately trivializes the analysis. Since Fitch’s theory of value is not the context in which the paradox is widely discussed, we will say no more about it here. 