A Refutation of the Lewis-Stalnaker Analysis of Counterfactuals

The standard philosophical analysis of counterfactual conditionals—the Lewis-Stalnaker analysis—analyzes the truth-conditions of counterfactuals in terms of nearby possible worlds. This paper demonstrates that this analysis is false. §1 shows that it is a serious epistemic and metaphysical possibility that our “world” is a massive computer simulation, and that if the Lewis-Stalnaker analysis of counterfactuals is correct, then it should extend seamlessly to the case that our world is a computer simulation, in the form of a possible-simulation semantics. §2 then shows, however, that a Lewis-Stalnaker-style possible-simulation semantics clearly fails as an analysis of the truth-conditions of counterfactuals in two types of simulated worlds: Humean Simulations and Necessitarian simulations. §3 then considers and answers several objections to the argument. Finally, §4 draws several skeptical, but compelling lessons about counterfactuals from the argument.