Research Seminar in Decision and Action Theory: Alan Hájek (ANU)

Title:

A Chancy Theory of Counterfactuals

Abstract:

I have long argued against the Stalnaker/Lewis ‘similarity’ accounts of counterfactuals. Roughly, they say that the counterfactual
if p were the case, q would be the case
is true if and only if
at the most similar p-worlds, q is true.
Most philosophers agree with this. I disagree. I will summarise my main arguments against this entire approach and add some new ones.
I will offer a paradigm shift based on conditional chances. The counterfactual is true if the chance of q, given p, equals 1 at a time shortly, but not too shortly, before the truth value of p was settled. I will argue that this account has many advantages over the similarity accounts.
What are the chances? I will present my version of a propensity account, and I will argue that it avoids the main objections that have been levelled against propensities. In short, I offer a conditional propensity account of counterfactuals.