Actualism, Possibilism, and the Nature of Consequentialism

The actualism/possibilism debate in ethics is about whether counterfactuals of freedom concerning what an agent would freely do if they were in certain circumstances even partly determines that agent’s obligations. This debate arose from an argument against the coherence of utilitarianism in the deontic logic literature. In this chapter, we first trace the historical origins of this debate and then examine actualism, possibilism, and securitism through the lens of consequentialism. After examining their respective benefits and drawbacks, we argue that, contrary to what has been assumed, actualism and securitism both succumb to the so-called nonratifiability problem. In making this argument, we develop this problem in detail and argue that it’s a much more serious problem than has been appreciated. We conclude by arguing that an alternative view, hybridism, is independently the most plausible position and best fits with the nature of consequentialism, partly in light of avoiding the nonratifiability problem

Frontiers of Conditional Logic

Conditional logics were originally developed for the purpose of modeling intuitively correct modes of reasoning involving conditional—especially counterfactual—expressions in natural language. While the debate over the logic of conditionals is as old as propositional logic, it was the development of worlds semantics for modal logic in the past century that catalyzed the rapid maturation of the field. Moreover, like modal logic, conditional logic has subsequently found a wide array of uses, from the traditional (e.g. counterfactuals) to the exotic (e.g. conditional obligation). Despite the close connections between conditional and modal logic, both the technical development and philosophical exploitation of the latter has outstripped that of the former, with the result that noticeable lacunae exist in the literature on conditional logic. My dissertation addresses a number of these underdeveloped frontiers, producing new technical insights and philosophical applications. I contribute to the solution of a problem posed by Priest of finding sound and complete labeled tableaux for systems of conditional logic from Lewis\u27 V-family. To develop these tableaux, I draw on previous work on labeled tableaux for modal and conditional logic; errors and shortcomings in recent work on this problem are identified and corrected. While modal logic has by now been thoroughly studied in non-classical contexts, e.g. intuitionistic and relevant logic, the literature on conditional logic is still overwhelmingly classical. Another contribution of my dissertation is a thorough analysis of intuitionistic conditional logic, in which I utilize both algebraic and worlds semantics, and investigate how several novel embedding results might shed light on the philosophical interpretation of both intuitionistic logic and conditional logic extensions thereof. My dissertation examines deontic and connexive conditional logic as well as the underappreciated history of connexive notions in the analysis of conditional obligation. The possibility of interpreting deontic modal logics in such systems (via embedding results) serves as an important theoretical guide. A philosophically motivated proscription on impossible obligations is shown to correspond to, and justify, certain (weak) connexive theses. Finally, I contribute to the intensifying debate over counterpossibles, counterfactuals with impossible antecedents, and take—in contrast to Lewis and Williamson—a non-vacuous line. Thus, in my view, a counterpossible like If there had been a counterexample to the law of the excluded middle, Brouwer would not have been vindicated is false, not (vacuously) true, although it has an impossible antecedent. I exploit impossible (non-normal) worlds—originally developed to model non-normal modal logics—to provide non-vacuous semantics for counterpossibles. I buttress the case for non-vacuous semantics by making recourse to both novel technical results and theoretical considerations

Weak and Strong Necessity Modals: On Linguistic Means of Expressing "A Primitive Concept OUGHT"

This paper develops an account of the meaning of `ought', and the distinction between weak necessity modals (`ought', `should') and strong necessity modals (`must', `have to'). I argue that there is nothing specially ``strong'' about strong necessity modals per se: uses of `Must p' predicate the (deontic/epistemic/etc.) necessity of the prejacent p of the actual world (evaluation world). The apparent ``weakness'' of weak necessity modals derives from their bracketing whether the necessity of the prejacent is verified in the actual world. `Ought p' can be accepted without needing to settle that the relevant considerations (norms, expectations, etc.) that actually apply verify the necessity of p. I call the basic account a modal-past approach to the weak/strong necessity modal distinction (for reasons that become evident). Several ways of implementing the approach in the formal semantics/pragmatics are critically examined. The account systematizes a wide range of linguistic phenomena: it generalizes across flavors of modality; it elucidates a special role that weak necessity modals play in discourse and planning; it captures contrasting logical, expressive, and illocutionary properties of weak and strong necessity modals; and it sheds light on how a notion of `ought' is often expressed in other languages. These phenomena have resisted systematic explanation. In closing I briefly consider how linguistic inquiry into differences among necessity modals may improve theorizing on broader philosophical issues

What if God commanded something horrible? A pragmatics-based defence of divine command metaethics

The objection of horrible commands claims that divine command metaethics is doomed to failure because it is committed to the extremely counterintuitive assumption that torture of innocents, rape, and murder would be morally obligatory if God commanded these acts. Morriston, Wielenberg, and Sinnott-Armstrong have argued that formulating this objection in terms of counterpossibles is particularly forceful because it cannot be simply evaded by insisting on God’s necessary perfect moral goodness. I show that divine command metaethics can be defended even against this counterpossible version of the objection of horrible commands because we can explain the truth-value intuitions about the disputed counterpossibles as the result of conversational implicatures. Furthermore, I show that this pragmatics-based defence of divine command metaethics has several advantages over Pruss’s reductio counterargument against the counterpossible version of the objection of horrible commands

Ceteris paribus conditionals and comparative normalcy

Our understanding of subjunctive conditionals has been greatly enhanced through the use of possible world semantics and, more precisely, by the idea that they involve variably strict quantification over possible worlds. I propose to extend this treatment to ceteris paribus conditionals – that is, conditionals that incorporate a ceteris paribus or ‘other things being equal’ clause. Although such conditionals are commonly invoked in scientific theorising, they traditionally arouse suspicion and apprehensiveness amongst philosophers. By treating ceteris paribus conditionals as a species of variably strict conditional I hope to shed new light upon their content and their logic

Obligations to Merely Statistical People

In some cases the morality of action is an inter‐personal affair. I am obliged to do something and there is a person to whom I am obliged to do it. I do wrong and there is a person I wrong. Some routine examples: I do wrong, and wrong you, by doing something bad for you, by feeding you contaminated meat. I do wrong, and wrong you, by failing to do something good for you, by ignoring your S.O.S. I do wrong, and wrong you, by violating your rights, by stealing your stuff. I do wrong, and wrong you, by disrespecting you, by brazenly discounting your opinions

Conditionals and modularity in general logics

In this work in progress, we discuss independence and interpolation and related topics for classical, modal, and non-monotonic logics