'Ought' Implies 'Can' and the Argument from Self-Imposed Impossibility: a Critical Examination

Defenders of the Kantian maxim, i.e. ‘ought’ implies ‘can’, defend the maxim taking the term “implication” in the sense of ‘entailment’. But if it is granted that “implication” means entailment, then it can be shown that the Kantian maxim that ‘ought’ implies ‘can’ is false. Sinnott-Armstrong attempts to prove the falsity of the maxim by his argument from Self-Imposed Impossibility in which he offers his famous example of Adams. But Sinnott-Armstrong’s example of Adams appears to be not strong enough to prove the falsity of the maxim; it is a subject to be captured by a version of the maxim, namely the Maxim-KT. That is why two new examples of the argument from Self-Imposed Impossibility are presented in this paper which are stronger and are able to prove the falsity of the Kantian maxim.