I argue that if one applies the standard intuitionistic criterion for truth to Kp in (p) (p&Kp), one avoids Fitch’s paradox, but with disastrous consequences having to do with the expressive resources of one’s semantics. On the other hand, if one conceives of Kp as a function recording what happens in the actual world, one gets a double benefit. First, the semantics become tolerably expressive. Second, and because of the same move, the paradox can be blocked. (The solution I provide bares resemb…
Read moreI argue that if one applies the standard intuitionistic criterion for truth to Kp in (p) (p&Kp), one avoids Fitch’s paradox, but with disastrous consequences having to do with the expressive resources of one’s semantics. On the other hand, if one conceives of Kp as a function recording what happens in the actual world, one gets a double benefit. First, the semantics become tolerably expressive. Second, and because of the same move, the paradox can be blocked. (The solution I provide bares resemblances with the ones proposed by Edgington 1985, 2009 and Kvanvig 1995, 2006, and especially with this latter as it has been reformulated by Brogaard and Salerno 2007). Finally, I shown that in some models for temporal intuitionistic logic (Kapantaïs 2009), and which are extensions of Beth models, (i) the knowability principle can be assumed to be valid, (ii) the paradox is blocked in the above mentioned way, and also (iii) a sentence saying that we will come to know something we now ignore becomes true and known in some worlds.