A Chancy Theory of Counterfactuals

Alan Hajek (Australian National University)

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 iff 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.