 What is more, Prichard thinks that even if it were true that we ought to aim at this end, it would not follow that we ought to do what (we think) will lead to it. The derived ‘ought’ here can only be identical with the sort of ‘ought’ that we derive in non-moral cases, as when we say to a poisoner ‘you ought to give a second dose’, and such an ‘ought’ has no force for those who have not adopted the relevant end. This is partly because it is not true that we have a moral duty to do those actions that will lead to outcomes that we have a duty to aim at. We might, for instance, have a duty to help the sick, and it may be that the only way to achieve that end is to write begging letters to our more prosperous friends. But it does not follow that we have a duty to write those letters. It will be true that we ought to write those letters, but this only means (says Prichard) that if we do not write them, we will not achieve our end. The ‘ought’ here is the non-moral ‘ought’.