Practical judgements (such as ‘I must/ought to ’) are commonly to be understood relatively to a set of ends, quasi-ends (e.g., side-constraints), and circumstances. One can ask: necessary/fitting for what, in virtue of what? It may be true that I must , in order to , because my end is to , although there is no necessity for me to : necessities can be superficial. It is the agent's ends and quasi-ends that play a role in his own deliberations. Yet a speaker can invoke what ends and quasi-ends he likes, and say what the agent must/ought to do relatively to those. ‘Ought’s may be all-in, or pro tanto. The practical ‘ought’ is an operator upon predicates, not sentences. ‘Ought’ entails ‘can’ and ‘may’ relatively to a constant set of circumstances.
Keywords: must, ought, end, quasi-end, circumstances, relative