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Other Philosophy Papers

Diachronic Rationality and Prediction-Based Games (2010)

Proceedings of the Aristotelian Society 110 (2010) pp. 243-266

I explore the debate about causal versus evidential decision theory, and its recent developments in the work of Andy Egan, through the method of some simple games based on agents' predictions of each other's actions. My main focus is on the requirement for rational agents to act in a way which is consistent over time and its implications for such games and their more realistic cousins.

Justifying conditionalisation: conditionalisation maximises expected epistemic utility (March 2005)

(Hilary Greaves and DW)

Mind 115 (2006) pp. 607-632

According to Bayesian epistemology, the epistemically rational agent updates her beliefs by conditionalization: that is, her posterior subjective probability after taking account of evidence X, pnew, is to be set equal to her prior conditional probability pold(.|X). Bayesians can be challenged to provide a justification for their claim that conditionalization is recommended by rationality --- whence the normative force of the injunction to conditionalize?

There are several existing justifications for conditionalization, but none directly addresses the idea that conditionalization will be epistemically rational if and only if it can reasonably be expected to lead to epistemically good outcomes. We apply the approach of cognitive decision theory to provide a justification for conditionalization using precisely that idea. We assign epistemic utility functions to epistemically rational agents; an agent's epistemic utility is to depend both upon the actual state of the world and on the agent's credence distribution over possible states. We prove that, under independently motivated conditions, conditionalization is the unique updating rule that maximizes expected epistemic utility.

Protecting cognitive science from quantum theory (2004)

Behavioral and Brain Sciences 27 (2004), pp. 636-637

The relation between micro-objects and macro-objects advocated by Kim is even more problematic than Ross & Spurrett (R&S) argue, for reasons rooted in physics. R&S's own ontological proposals are much more satisfactory from a physicist's viewpoint but may still be problematic. A satisfactory theory of macroscopic ontology must be as independent as possible of the details of microscopic physics.

(Note: Behavioral and Brain Sciences is an interdisciplinary journal in the psychology/cognitive science/AI/philosophy-of-mind nexus. It typically publishes a "target article", several dozen short responses, and then a reply from the authors of the target article. This is my reply to D. Ross and D. Spurrett, What to say to a skeptical metaphysician: A defense manual for cognitive and behavioral scientists, BBS 27 (2004) pp. 603-627.)