 If we are committed to the Categorical Analysis, then those desiring to defend compatibilism seem to be committed to the sense of ability in ‘is able to break a law of nature’ along the lines of the strong thesis. Lewis agrees with van Inwagen that it is “incredible” to think humans have such an ability (Lewis 1981, 113), but maintains that compatibilists need only appeal to the ability to break a law of nature in the weak sense. While it is absurd to think that humans are able to do something that is a violation of a law of nature or causes a law of nature to be broken, there is nothing incredible, so Lewis claimed, in thinking that humans are able to do something such that if they did it, a law of nature would be broken. In essence, Lewis is arguing that incompatibilists like van Inwagen have failed to adequately motivate the restrictiveness of the Categorical Analysis.