This paper concerns a controversy between two compelling and popular claims in the theory of ability. One is the claim that ability requires control. The other is the claim that success entails ability, that is, that φ-ing entails that you are able to φ. Since actually φ-ing obviously does not entail that φ is in your control, these two claims cannot both be true. I introduce a new form of evidence to help adjudicate this controversy: judgments about the possibility and (...) probability of ability ascriptions. I argue that these judgments provide evidence in favor of the thesis that success entails ability, and against the thesis that ability requires control. Moreover, I argue that these judgments support an analysis of ability in terms of conditionals. (shrink)

Recent work by Alfred Mele, Romy Jaster and Chandra Sripada recognizes that abilities come in degrees of fallibility. The rough idea is that abilities are often not surefire. They are liable to fail. The more liable an ability is to fail, the more fallible it is. Fallibility is plausibly significant for addiction, responsibility, and normative theorizing. However, we lack an adequate account of what fallibility consists in. This article addresses that problem. Perhaps the most natural approach is to say (roughly) (...) the fallibility of your ability to F is the proportion of scenarios in which you do not F, among those in which you try to F. I argue that this approach (in all plausible versions) is mistaken. I then introduce the notion of an action’s “fragility,” and propose that we use that new notion to understand fallibility. (shrink)