Beyond the Magical Thinking behind the Principal Principle

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David Lewis's Principal Principle (PP) states that our credence in a single case follows from the general probability of all such cases. Against this stands the Challenge Argument (CA) – to show that the inference is justified. Recent (1) law-to-chance, (2) Bayesian, and (3) propensity theories of probability take up the challenge – but, I argue, fall short. Rather, we should understand (4) propensity via Aristotle's analysis of spontaneity (5) and probabilistic reasoning via the Anti-PP and (6) the practice of bundling one offs, where (7) forced bad-odds one offs illuminate how extensive a role luck plays in our lives.

Original Citation

James, E. (2015). Beyond the Magical Thinking behind the Principal Principle. Philosophy, 90 (3), 479-503. https://doi.org/10.1017/S0031819115000121