
A Simpler and More Realistic Subjective Decision TheorySynthese 195 (10). 2018.In his classic book “the Foundations of Statistics” Savage developed a formal system of rational decision making. The system is based on (i) a set of possible states of the world, (ii) a set of consequences, (iii) a set of acts, which are functions from states to consequences, and (iv) a preference relation over the acts, which represents the preferences of an idealized rational agent. The goal and the culmination of the enterprise is a representation theorem: Any preference relation that satisf…Read more

Frege's Begriffsschrift is Indeed FirstOrder CompleteHistory and Philosophy of Logic 38 (4): 342344. 2017.It is widely taken that the firstorder part of Frege's Begriffsschrift is complete. However, there does not seem to have been a formal verification of this received claim. The general concern is that Frege's system is one axiom short in the firstorder predicate calculus comparing to, by now, the standard firstorder theory. Yet Frege has one extra inference rule in his system. Then the question is whether Frege's firstorder calculus is still deductively sufficient as far as the firstorder co…Read more

"Click!" Bait for CausalistsIn Arif Ahmed (ed.), Newcomb's Problem, Cambridge University Press. pp. 160179. 2018.Causalists and Evidentialists can agree about the right course of action in an (apparent) Newcomb problem, if the causal facts are not as initially they seem. If declining $1,000 causes the Predictor to have placed $1m in the opaque box, CDT agrees with EDT that oneboxing is rational. This creates a difficulty for Causalists. We explain the problem with reference to Dummett's work on backward causation and Lewis's on chance and crystal balls. We show that the possibility that the causal facts …Read more

Heart of DARCnessAustralasian Journal of Philosophy 115. forthcoming.There is a longstanding disagreement in the philosophy of probability and Bayesian decision theory about whether an agent can hold a meaningful credence about an upcoming action, while she deliberates about what to do. Can she believe that it is, say, 70% probable that she will do A, while she chooses whether to do A? No, say some philosophers, for Deliberation Crowds Out Prediction (DCOP), but others disagree. In this paper, we propose a valid core for DCOP, and identify terminological causes …Read more

Ramsey and Joyce on Deliberation and PredictionSynthese 122. forthcoming.Can an agent deliberating about an action A hold a meaningful credence that she will do A? 'No', say some authors, for 'Deliberation Crowds Out Prediction' (DCOP). Others disagree, but we argue here that such disagreements are often terminological. We explain why DCOP holds in a Ramseyian operationalist model of credence, but show that it is trivial to extend this model so that DCOP fails. We then discuss a model due to Joyce, and show that Joyce's rejection of DCOP rests on terminological choic…Read more

The Surething Principle and P2Economics Letters 159 221223. 2017.This paper offers a fine analysis of different versions of the well known surething principle. We show that Savage's formal formulation of the principle, i.e., his second postulate (P2), is strictly stronger than what is intended originally.

Contextdependent UtilitiesIn Wiebe Van Der Hoek, Wesley H. Holliday & Wen Fang Wang (eds.), Logic, Rationality, and Interaction, Springer. pp. 90101. 2015.Savage's framework of subjective preference among acts provides a paradigmatic derivation of rational subjective probabilities within a more general theory of rational decisions. The system is based on a set of possible states of the world, and on acts, which are functions that assign to each state a consequence. The representation theorem states that the given preference between acts is determined by their expected utilities, based on uniquely determined probabilities (assigned to sets of sta…Read more

Countable Additivity, Idealisation, and Conceptual RealismEconomics and Philosophy. forthcoming.This paper addresses the issue of finite versus countable additivity in Bayesian probability and decision Theory  in particular, Savage's theory of subjective expected utility and personal probability. I show that Savage's reason for not requiring countable additivity in his theory is inconclusive. The assessment leads to an analysis of various highly idealised assumptions commonly adopted in Bayesian theory, where I argue that a healthy dose of, what I call, conceptual realism is often helpfu…Read more
Cambridge, Cambridgeshire, United Kingdom of Great Britain and Northern Ireland
Areas of Specialization
Logic and Philosophy of Logic 
Philosophy of Probability 
Decision Theory 
Philosophy of Artificial Intelligence 