John Cantwell

The view that decision methods can only be justified by appeal to pragmatic considerations is defended. Pragmatic considerations are viewed as providing the underlying subject matter (“semantics”) of decision theories. It is argued that other approaches (e.g. justifying principles by appeal to obviousness, common usage, etc.) fail to provide grounds for a normative decision theory.It is argued that preferences that can lead to pragmatically adverse outcomes in a relevantly similar possible decision situation are pragmatically unsound, even if the decision situation never arises. This rebuts several standard objections to money-pump and Dutch book arguments. However, because one can only appeal to relevantly similar decision situations in pragmatic arguments, these will have a less general scope than is often imagined. A conclusion is that pragmatic arguments for strong unconditional principles such as ‘always maximise expected utility!’ do not work. Pragmatic considerations can however be used to argue for conditional principles of the form ‘if conditions X, Y and Z are satisfied, then one ought to satisfy W’, where W need not follow logically from X, Y and Z.The notion of a sound pragmatic argument is defined in terms of particular notion of coherence, it is shown how this can be applied and how it handles problematic cases such as van Fraassen’s Dutch book for the principle of Reflection.

It is shown that two simple principles N and P concerning probabilities of conditionals can be combined with the standard ratio analysis of conditional probability only at the expense of complete triviality: no measure that satisfies all three can assign any proposition a non-trivial probability (probability greater than 0 and less than 1). The proof of this is trivial. Moreover, N and P are shown to follow from the Ramsey Test, Import–Export, Reflexivity and a weak principle of suppositional consistency (entailed by the ratio analysis), as well as from considerably weaker plausible properties. Together the results constitute a triviality result with a very strong conclusion from very weak premises, with a trivial proof. It sharpens the question: which principle is to blame?

It is argued that David Lewis' two triviality results (the probability of the conditional cannot be the conditional probability; desire cannot be belief) both present a potential problem for expressivism, are related, and can both be resolved in the same way: by allowing for gappy propositions (propositions that can lack truth value). In particular, a semantics for 'A is good' is provided that allows one to embrace the major premises leading up to Lewis' triviality result while avoiding its conclusion. © 2016 Elsevier B.V., All rights reserved.

The typical function of goals is to regulate action in a way that furthers goal achievement. Goals are typically set on the assumption that they will help bring the agent(s) closer to the desired state of affairs. However, sometimes endorsement of a goal, or the processes by which the goal is set, can obstruct its achievement. When this happens, the goal is self-defeating. Self-defeating goals are common in both private and social decision-making but have not received much attention by decision theorists. In this paper, we investigate different variants of three major types of selfdefeating mechanisms: (1) The goal can be an obstacle to its own fulfilment (self-defeating goal endorsement), (2) goal-setting activities can impede goal achievement (self-defeating goalsetting), and (3) disclosure of the goal can interfere with its attainment (self-defeating goal disclosure). Different strategies against self-defeasance are tentatively explored, and their efficiency against different types of self-defeasance is investigated.

Conditional constructions – constructs of the form If A, then B – have for over a century been subject to intense study in a wide variety of philosophical areas, as well as outside of philosophy. One important reason is that such constructs allow one to encode connections and dependencies, be they causal, epistemic, conceptual, or metaphysical. This chapter briefly outlines some of the main formal models that have been employed to analyze such constructs, as well as their philosophical motivation.

A semantics is presented for belief-revision in the face of common announcements to a group of agents that have beliefs about each other's beliefs. The semantics is based on the idea that possible worlds can be viewed as having an internal structure, representing the belief independent features of the world, and the respective belief states of the agents in a modular fashion. Modularity guarantees that changing one aspect of the world (a belief independent feature or a belief state) has no effect on any other aspect of the world. This allows us to employ an AGM-style selection function to represent revision. The semantics is given a complete axiomatisation (identical to the axiomatisation found by Gerbrandy and Groeneveld for a semantics based on non-wellfounded set theory) for the special case of expansion.

Statements containing epistemic modals (e.g., “by spring 2023 most European countries may have the Covid-19 pandemic under control”) are common expressions of epistemic uncertainty. In this paper, previous published findings (Knobe & Yalcin, 2014; Khoo & Phillips, 2018) on the opposition between Contextualism and Relativism for epistemic modals are re-examined. It is found that these findings contain a substantial degree of individual variation. To investigate whether participants differ in their interpretation of epistemic modals, an experiment with multiple phases and sessions is used to classify participants according to the three semantic theories of Relativism, Contextualism, and Objectivism. Through this study, some of the first empirical evidence for the kind of truth-value shifts postulated by semantic Relativism is presented. It is furthermore found that participants’ disagreement judgments match their truth evaluations and that participants are capable of distinguishing between truth and justification. In a second experimental session, it is investigated whether participants thus classified follow the norm of retraction which Relativism uses to account for argumentation with epistemic modals. Here the results are less favorable for Relativism. In a second experiment, these results are replicated and the normative beliefs of participants concerning the norm of retraction are investigated following work on measuring norms by Bicchieri (2017). Again, it is found that on average participants show no strong preferences concerning the norm of retraction for epistemic modals. Yet, it was found that participants who had committed to Objectivism and had training in logics applied the norm of retraction to might-statements. These results present a substantial challenge to the account of argumentation with epistemic modals presented in MacFarlane (2014), as discussed. Keywords: Epistemic Modals, Relativism, Norm Conflicts, Retraction, Semantics, Truth Conditions, Argumentation.

Conditional constructions – constructs of the form If A, then B – have for over a century been subject to intense study in a wide variety of philosophical areas, as well as outside of philosophy. One important reason is that such constructs allow one to encode connections and dependencies, be they causal, epistemic, conceptual, or metaphysical. This chapter briefly outlines some of the main formal models that have been employed to analyze such constructs, as well as their philosophical motivation.