Of prima facie duties I suggest, without claiming completeness or finality for it, the following division.

(1) Some duties rest on previous acts of my own. These duties seem to include two kinds, (a) those resting on a promise or what may fairly be called an implicit promise, such as the implicit undertaking not to tell lies which seems to be implied in the act of entering into conversation (at any rate by civilized men), or of writing books that purport to be history and not fiction. These may be called the duties of fidelity. (b) Those resting on a previous wrongful act. These may be called the duties of reparation. (2) Some rest on previous acts of other men, i.e. services done by them to me. These may be loosely described as the duties of gratitude. (3) Some rest on the fact or possibility of a distribution of pleasure or happiness (or of the means thereto) which is not in accordance with the merit of the persons concerned; in such cases there arises a duty to upset or prevent such a distribution. These are the duties of justice. (4) Some rest on the mere fact that there are other beings in the world whose condition we can make better in respect of virtue, or of intelligence, or of pleasure. These are the duties of beneficence. (5) Some rest on the fact that we can improve our own condition in respect of virtue or of intelligence. These are the duties of self-improvement. (6) I think that we should distinguish from (4) the duties that may be summed up under the title of ‘not injuring others’. No doubt to injure others is incidentally to fail to do them good; but it seems to me clear that non-maleficence is apprehended as a duty distinct from that of beneficence, and as a duty of a more stringent character. It will be noticed that this alone among the types of duty has been stated in a negative way. An attempt might no doubt be made to state this duty, like the others, in a positive way. It might be said that it is really the duty to prevent ourselves from acting either from an inclination to harm others or from an inclination to seek our own pleasure, in doing which we should incidentally harm them. But on reflection it seems clear that the primary duty here is the duty not to harm others, this being a duty whether or not we have an inclination that if followed would lead to our harming them; and that when we have such an inclination the primary duty not to harm others gives rise to a consequential duty to resist the inclination. The recognition of this duty of non-maleficence is the first step on the way to the recognition of the duty of beneficence; and that accounts for the prominence of the commands ‘thou shalt not kill’, ‘thou shalt not commit adultery’, ‘thou shalt not steal’, ‘thou shalt not bear false witness’, in so early a code as the Decalogue. But even when we have come to recognize the duty of beneficence, it appears to me that the duty of non-maleficence is recognized as a distinct one, and as prima facie more binding. We should not in general consider it justifiable to kill one person in order to keep another alive, or to steal from one in order to give alms to another.

(W. D. Ross, The Right and the Good [1930; repr., Indianapolis/Cambridge: Hackett Publishing Company, 1988], 20-2 [boldface added; footnotes omitted])