Outline of “Nihil Obstat: An Analysis of Ability”

Abstract

This outline for a paper, which develops a compatibilist analysis of abilities, was completed by David Lewis during his sabbatical in the Fall semester of 2000 and is dated 20 January 2001. Starting from the claim that it’s a “Moorean fact” that we are often able to do otherwise, Lewis provides a “simple proof of compatibilism.” He then presents his own account of abilities: S is able to A if and only if there are no obstacles to their A-ing, where an obstacle is a “robust preventer”: something that would (or does) cause S not to A, and which “wouldn’t go away if things were just a little different.”