Luminosity Failure, Normative Guidance and the Principle ‘Ought-Implies-Can’

It is widely thought that moral obligations are necessarily guidance giving. This supposed fact has been put to service in defence of the ‘ought-implies-can’ principle according to which one cannot be morally obligated to do the impossible, since impossible-to-satisfy obligations would not give guidance. It is argued here that the supposed fact is no such thing; moral obligations are not necessarily guiding giving, and so the ‘guidance argument’ for ought-implies-can fails.