Anglo-Catholic Ninjas

‘Ought’ is a normative term. A statement that includes it as the main verb typically prescribes or proscribes some action or inaction. “I ought to cross the road only when the light is green”, “You ought to attend Mass” and “We ought not to help rude Martians” all entail some imperative to act or not act (not-act = refrain from doing X). Following Gilbert Harman, however, we can distinguish between four types of judgements using ‘ought’. Not all ‘ought’ statements are prescriptive in the aforementioned sense.

1. the ought of expectation
2. the ought of rationality
3. the ought of evaluation
4. the ought of morality

Example judgements that correspond with the above typology are:

1. Oscar ought to be here by now.
2. No child ought to die from hunger.
3. The thief ought to wear gloves.
4. I ought to keep my promises.

Harman calls the second kind of ‘ought’ evaluative. It is seen in the example claim that “No child ought to die from hunger”. This judgement can be genuinely normative, even if it registers no overriding requirement to act (or not act) – in a better world, no child would starve to death, but, for all that, it is not necessarily the case that the agent who makes this judgement should bring about that state of affairs (it may be impossible for the agent to achieve this, regardless of how better an outcome it is).

The fourth ‘ought’ is generally considered the prescriptive or imperative term. Presumably, the agent who judges that she should keep her promises is committed to acting that way in relevant circumstances. So this is an action-guiding ‘ought’, and, since morality concerns actions at some level, it is also the moral ‘ought’. 

Bibliography: An Introduction to Ethics: Five Central Problems of Moral Judgement, by Geoffrey Thomas (London: Gerald Duckworth & Co. Ltd., 1993)