All over there are arguments that employ the following premise: Necessarily, the true moral theory is action-guiding. I must confess that I don’t really have a grip on what this notion is. And yet it is often appealed to to do some very heavy-lifting: most often to establish that some form of subjectivism about moral obligation is true and also that ‘Ought’ Implies ‘Can’ is true. But given that I don’t understand what this action-guidingness is supposed to amount to, I don’t know how to understand these arguments, let alone evaluate them. Mayhaps someone here can help me out with this. Can anyone articulate for me in a non-metaphorical way what it means to say that a theory is action-guiding?