Joseph Salerno

Remarks on counterpossibles

Since the publication of David Lewis’ Counterfactuals, the standard line on subjunctive conditionals with impossible antecedents (or counterpossibles) has been that they are vacuously true. That is, a conditional of the form ‘If p were the case, q would be the case’ is trivially true whenever the antecedent, p, is impossible. The primary justification is that Lewis’ semantics best approximates the English subjunctive conditional, and that a vacuous treatment of counterpossibles is a consequence of that very elegant theory. Another justification derives from the classical lore than if an impossibility were true, then anything goes. In this paper we defend non-vacuism, the view that counterpossibles are sometimes non-vacuously true and sometimes non-vacuously false. We do so while retaining a Lewisian semantics, which is to say, the approach we favor does not require us to abandon classical logic or a similarity semantics. It does however require us to countenance impossible worlds. An impossible worlds treatment of counterpossibles is suggested (but not defended) by Lewis (Counterfactuals. Blackwell, Oxford, 1973), and developed by Nolan (Notre Dame J Formal Logic 38:325–527, 1997), Kment (Mind 115:261–310, 2006a: Philos Perspect 20:237–302, 2006b), and Vander Laan (In: Jackson F, Priest G (eds) Lewisian themes. Oxford University Press, Oxford, 2004). We follow this tradition, and develop an account of comparative similarity for impossible worlds.

Introduction to knowability and beyond

Beyond the limits of human knowledge lies nothing at all—no understandable proposition whose truth may outrun our idealized epistemic capacities. So says the semantic anti-realist, who advocates an epistemic theory of truth—one for which, as a matter of metaphysical necessity, anything true is knowable in principle. The interesting idealization remains elusive but is meant to lie somewhere between the triviality of equating truth with God’s knowledge (uninformative realism) and the naivety of equating it with what humans actually know (naive idealism). The former offers no explanatory gain, and the latter fails to appreciate the objectivity and discoverability of truth. The middle way aims for something like this: barring vagueness and ambiguity, we could in principle know the truth value of any fully understood proposition, given only finite improvements to our epistemic capacities, resources or environment. Call this “moderate anti-realism”. Many forms of non-realism are in the neighborhood of the thesis, including some versions of ethical expressivism, Michael Dummett’s mathematical intuitionism, Putnamian internal realism, Peircean pragmatism, logical positivism, Kantian transcendental realism, and Berkeleyian idealism. One great problem for our understanding of the middle way is the knowability paradox—also known as “Fitch’s paradox” because Frederic Fitch first published the result in 1963, and the “Church–Fitch paradox” because Church was the anonymous referee who conveyed it to Fitch in 1945.1 It consists of a proof that appears

Knowability and a New Paradox of Happiness

The paper examines the logic of the knowability paradox and a structural analogue, a new paradox of happiness. We develop a general understanding of what it is to be a Fitch paradox, and follow a natural thread in the literature that attempts to block or resolve Fitch paradoxes. We conclude that, in the case of the attitude of happiness, the new paradox remains even if one finds the knowability analogue non-threatening.