Robert L. Frazier ( )

Robert L. Frazier
Christ Church


To have a duty is, above all, to be subject to a binding, normative requirement. This means that unless there are exculpating reasons, someone who has a duty is required satisfy it, and can be justifiably criticized for not doing so. Having a duty to do something is like having been given a command to do it by someone who has a right to be obeyed: it must be done.

Sometimes we speak as if we have duties to individuals (e.g., persons and institutions). So, for example, if Jones makes a promise to Smith, then Jones has a duty to Smith to keep the promise. We also talk as if we have duties to perform, or to refrain from performing, types of actions, e.g., a duty to help those in need. Even if the performance of such a duty involves treating an individual in a certain way, the duty may not be to that individual. For example, a duty to be charitable might not be a duty to anyone, not even the recipient of the charity.

An important feature of duties is that they provide some justifying reason for action. If we explain why we did something by saying that it was our duty, we are offering a justification for the action. Such a justifying reason does not depend on the entire nature of the action. For example, if we make a promise, we have some justifying reason for keeping it, regardless of what was promised, or to whom the promise was made. Again it is like a command. If we are given a command by someone with a right to be obeyed, we have some justification for obeying it, no matter what we are commanded to do. On some views, however, the justifying reason we have for doing something because it is required by duty may not be decisive: we may have an even better reason for doing something else. Nonetheless, that something is required by duty provides some justifying reason for doing it.

Talk about duties is found in many areas; we speak, for example, of legal duties, moral duties, professional duties, the duties of a scholar and, even, matrimonial duties. This discussion will focus on moral duty, but may have wider application.

1 Duty and other normative concepts
2 Kinds of Duties
3 The Grounds of Duties

Duty and other normative concepts

Related to the concept of duty are a number of other important normative concepts. Among these are the concepts of obligation, right, permission and prohibition. The relations between permissions, prohibitions and duties are fairly straightforward: if we are permitted to do something, then we do not have a duty not to do it; if we are prohibited from doing something, we have a duty not to do it (see DEONTIC LOGIC). The relationships between duties, obligations and rights are not as obvious.

According to most modern use, obligation and duty are taken to be coextensive, if not identical. So, to have a duty to do something is the same as to have an obligation to do it. However, there is a narrower view concerning duty. According to this, duties must result from our roles (e.g., statuses, occupations, or positions). For example, subjects are said to have duties to their sovereign, physicians to their patients and parents to their children. The duty arises from the role, e.g., being a subject, physician, or parent. Obligations are distinct from duties on this view. Obligations only result from voluntary actions, e.g., an obligation might result from the making of a promise. It may be that distinction between duties and obligations is currently seldom recognized because many of the roles we have are taken on voluntarily. Although there is much to be said for the narrower view, for the rest of this essay current usage will be followed and it will be assumed that duties and obligations are substantially the same.

One important view about the relationship between rights (see RIGHTS) and duties is that there is a correlation between, at least, some rights and duties. A version of this thesis is expressed in the two following principles.

  1. A right of A against B implies a duty of B to A.
  2. A duty of B to A implies a right of A against B. [Ross, 1930, p. 48]

It should be noted that accepting these principles does not force us to accept the less plausible view that there is a general correlation between rights and duties, where every right implies a duty and every duty implies a right. As has been pointed out, there may be duties concerning individuals which are not duties to those individuals. Likewise, individuals may have rights which are not rights against anyone in particular. About such cases the above principles are silent. Rather, the the proposal is that there is a correlation between, for example, Smith's having a a duty to Jones, and Jones's having a right against Smith.

An evaluation of these principles requires that we examine these questions: (i) What can have duties? (ii) To what can there be duties? (iii) What can have rights? (iv) Against what can there be rights?

The answers to (i) and (iv) are fairly clear. It is reasonable to think that in order for an entity to have a duty, or for there to be a right against it, that entity must be able to recognize that it is subject to a normative requirement, a cognitive ability lacked by beings that are not rational. Consequently, only persons (rational beings), such as humans, can have duties and we can only have rights against persons. This still leaves open whether non-persons can have rights and whether we can have duties to non-persons. Can we, for example, have duties to non-human animals, or, perhaps, the biosphere? Can such things have rights against us?

One important view is that non-rational beings cannot have rights and we cannot have duties to them. Again, the thought is that a required cognitive capacity is lacking. It is sometimes argued that having any right, let alone a right against someone, requires the ability to claim it. Even according to this view, however, we might have duties concerning non-persons, or with respect to them. We could, for example, have a duty not to cause non-persons unnecessary pain, without its being a duty to anyone. Accepting this view would not require rejection of either of the principles.

An alternative view argues that for an individual to have a right, or for us to have a duty to that individual, does not require that individual to have anything like the cognitive capacity needed to have a duty, or to be the sort of thing against whom others can have rights. The standards are different. Perhaps all that is needed is something being sentient, or having interests. If so, then we we could accept that some non-persons can have rights against us and that we can have duties to some non-persons. This also is consistent with both of the principles.

One possible reason for rejecting the second principle is the thought that we can have duties to ourselves, but cannot have rights against ourselves. The idea that persons can have rights against themselves is difficult to accept. That persons can have duties to themselves, e.g., that we can have a duty of self-improvement to ourselves, seems much more plausible. However, if we take it that a duty to a person involves what is owed to that person, then the idea is much less plausible: can we really owe anything to ourselves? Alternatively, it might be that we have duties that concern ourselves, without their actually being duties to ourselves. If this is so, then no reason has been offered for rejecting the two principles.

Kinds of Duties

A number of distinctions have been offered between types or kinds of duties. The most important of these distinctions are those between positive and negative duties, prima facie and `all-in' duties or `all things considered' duties, perfect and imperfect duties, and subjective and objective duties.

The distinction between positive and negative duties is supposed to rest on a more fundamental difference between acting and refraining from acting (see ACTION). The idea is that positive duties concern what we are required to do, while negative duties concern what we are required to refrain from doing. Examples of positive duties might be the duties to help others and to develop our talents. Examples of negative duties might be the duties not to lie and not to kill.

A concentration on negative duties is often associated with deontological theories (see DEONTOLOGY). According to such theories, morality largely consists of constraints on action, none of which we can morally violate, but which may be relevant only in a limited number of situations. Deontologists often hold that the distinction between positive and negative duties can be morally significant: the negative duties are more important, or more stringent than the positive ones. Indeed, it is sometimes held that there can be a duty not to bring about something, while there is no duty to prevent it from occurring (see DOCTRINE OF DOUBLE-EFFECT). For example, there might be a very stringent duty not to kill someone, while there is, at best, a much less stringent duty to save that person's life (see ABORTION; EUTHANASIA).

Teleological theories, especially consequentialist ones (see TELEOLOGY; PERFECTIONISM; CONSEQUENTIALISM), even if they recognize a distinction between positive and negative actions, generally do not consider it to underpin a difference between negative and positive duties that has any moral significance. Such theories are concerned with the promoting of values, and it does not matter whether the values are promoted by acting or refraining from acting. For example, if the value is respect for life, then it can be promoted equally well by refraining from killing and by saving lives.

While it seems reasonable to think that there is some difference between positive and negative actions, that this involves a morally significant difference is much more contentious. Views about this divide roughly along the same lines as do those concerning the relative advantages of deontological and teleological theories. No doubt this will remain a controversial issue as long as these approaches to duty compete.

An equally controversial and, possibly, equally important distinction is made between prima facie duties and `all-in' duties (see ROSS, W D). (Prima facie duties are sometimes called `pro tanto duties' or `duties other things being equal', while all-in duties are sometimes called `duties proper' or `duties all things considered'.) A prima facie duty is not, contrary to its literal meaning, something that merely appears to be a duty. Rather, to say that we have a prima facie duty to perform some action is supposed to express the idea that the action involves an important moral consideration, but one that can be (morally) out weighed, or overridden, by other moral considerations. For example, assume that an agent has a choice between keeping a promise and helping someone in need, but cannot do both. Keeping the promise is a prima facie duty because it involves the morally important consideration of fidelity; helping the person in need is also a prima facie duty as it involves the morally important consideration of beneficence. The agent's all-in duty depends on the nature of all the relevant prima facie duties. That is, an all-in duty is what duty requires all things considered, in particular, given all prima facie duties.

Part of the motivation for this distinction is the idea that (all-in) duties can always be satisfied: there are never any real conflicts of duties (see CONFLICTS OF OBLIGATION). Using this distinction, we can attempt to explain apparent conflicts of duties in terms of conflicts of prima facie duties. When it seems that we have a duty to do two things, when we cannot do both, this distinction allows us to say that they are not really competing duties, but merely competing prima facie duties. (In some cases, of course, we would be permitted to do either, but would not have a duty to do either.) However, that all apparent conflicts of duties or moral dilemmas can be explained away in this fashion is not obvious. There seem to be situations where agents have to choose between courses of action that are so horrible that none is acceptable and the agent should feel regret no matter what is done. Whether such cases involve real conflicts of duties depends on two things. First, it depends on whether we take dilemmas to exclude there being a correct answer to the question of what duty requires. It may be that we call something something a dilemma simply because the choices are so awful. Second, it depends on whether there is some inconsistency in feeling regret for doing something that was required by duty.

Regardless of the attitude that is taken to possible conflicts of duty, the notion of a prima facie duty faces difficulties. Foremost among these is the lack of a persuasive account of how all-in duty results from diverse prima facie duties. No satisfactory account has been given of the conditions under which one prima facie duty `overrides' another. Still, the distinction is one that is, and, no doubt, will continue to be widely invoked.

The view that there is a distinction between perfect and imperfect duties is attributed to Kant (see KANT). He said that a perfect duty `permits no exception in the interest of inclination' [Kant, 1753/1953, pp 84-85]. Although it is not clear exactly what he had in mind, one plausible view is that the distinction is between duties owed to particular individuals and duties that are not owed to anyone, but merely concern someone. If we have a duty to someone, then that person has a right against us. (Kant thinks that we can have duties to ourselves and may even think that we can have rights against ourselves.) If we have a duty that is not to anyone, then that duty does not involve a right against us. This, arguably, gives us more latitude in how to satisfy the duty. A duty not to kill is owed to each person, while a duty of charity is not owed to anyone, and can be satisfied by helping any of a number of persons. Perfect duties are usually associated with negative, stringent duties, while imperfect duties are associated with positive, less stringent duties.

Finally, if a theory allows for a difference between what a person sincerely considers to be required by duty and what is actually required by duty, then it can allow for a distinction between subjective and objective duty. Subjective duty is that which one sincerely takes to be one's duty, while objective duty is that which is actually required by duty. There are other notions closely related to subjective obligation, which are sometimes offered as accounts of subjective duty. One is the notion of that which duty probably requires; another is that which it would be most reasonable to think that duty requires. Each of the latter is distinct from subjective duty, as I have characterized it. One may be sincere but incorrect about what duty probably requires. Also, one may have a sincere belief about what duty requires, which is not the most reasonable belief one can have.

Grounds of Duties

Given that to have a duty is to be subject to a binding normative requirement, we might naturally wonder how it is that we could become subject to such a requirement. Who or what binds us? This, perhaps, is the most difficult and most interesting question concerning duties.

One tradition says that only God could be the source of our duties (see GOD; NATURAL LAW). Given God's existence (see NATURAL THEOLOGY), it might be thought that God has authority over us and can impose duties on us. God would then have a right to our obedience. Giving us the Ten Commandments can be thought of as one way that God has imposed duties on us. If this is correct, then we have a duty to obey them. A problem with this view is that it has the implication that if God does not exist, then there are no duties. Another problem with it is that it is unclear why we are required to do as God commands. That is, it is unclear why God has authority over us. Indeed, a similar question can be asked about anyone else (e.g., person, institution or society) that is supposed to be able to impose duties on us. Why should we think that they have the authority to impose duties on us, or what gives them the right to tell us what to do?

Perhaps instead of someone imposing duties on us, it is the structure of the universe itself that imposes the duties. On this view, duties (or moral laws) would be analogous to physical laws. Just as we are subject to physical laws, e.g., Newton's law of gravitation, we are subject to binding normative requirements, e.g., the duty to help others who are in need. It is not that the universe has authority over us and we must obey its command, rather it is that normativity is part of the very fabric of the universe.

Various problems with this view have been raised, of which I will briefly mention three. The first is that the features of the universe that produce the duty would be very strange, unlike anything else about which we know (see NATURALISM; PHYSICALISM; MACKIE, J L). The second is that we it is difficult to see how we could learn about these duties. We do not have any perceptual experience of them, and perceptual experience is widely thought to be the way that we gain knowledge about the world (see INTUITIONISM IN ETHICS). The third objection rests on the action guiding nature of duty. The idea is that it is a necessary feature of accepting something as being required by duty that we are to some extent motivated to do it. How is it that duties imposed on us by the structure of the world motivate us? (see MORAL MOTIVATION).

If duties are not imposed by things diverse from us, perhaps we impose them on ourselves. Indeed, as Kant argued, it might be that a duty can only be imposed by the person having it (see KANT). A non-Kantian expression of a similar idea is this. Only moral agents can have moral duties. Moral agents are responsible for their actions (see RESPONSIBILITY), and being responsible for an action requires that the agent does it freely (see FREE WILL AND DETERMINISM; RESPONSIBILITY). However, freedom is not sufficient for moral agency. For example, it seems that children are free, but not moral agents. Moral agency also requires that agents act rationally, that they act on reasons that they accept as adequate. This means an action is performed because of the nature of the action. If duties could be imposed on us by others, e.g., God, society, and the universe, then we would not be moral agents. We would not be acting on adequate reason because our reason for acting would not be the nature of the action. Instead, we would be acting because the action was imposed as a duty. It would be like obeying a command simply because it was a command and not because what was commanded was appropriate for the situation. So for something to be someone's duty, it must result from that person, i.e., only we can impose duties on ourselves. A similar point is this: moral agents have authority over themselves, but are subject to no other authority.

Numerous questions can be raised about the idea that we impose duties on ourselves. Why is giving ourselves reasons for actions imposing duties on ourselves? After all, if we have authority over ourselves, can we not change our duties at will? Indeed, what is it to have authority over ourselves? A possible answer to these questions is that the second condition of moral agency, that we act rationally or act from adequate reason, provides additional normative constraints on what we can do as moral agents. In particular, this condition may require a sort of impartiality: a reason for a rational agent acting in a certain way in a particular situation must be a reason for any ration agent to act in the same way in similar situations (see IMPARTIALITY; UNIVERSALIZABILITY).

If we were to accept that others cannot impose duties on us and we cannot impose duties on ourselves, would there any use for the notion of duty? Is the idea of a duty, of morality itself, a fiction to be discarded? Not necessarily. There could be other explanations of why we think that the notion of duty is relevant to our actions.

One position is that we cannot do without some notion of duty: it is a useful instrument (see INSTRUMENTALISM). On such an account, the reasons for accepting a system of morality would not be moral reasons. Instead, the reasons would be ones of self interest, or a combination of self interest and and interest in others. The idea is that people will generally be better off living in a society where there are social institutions and conventions regulating behaviour (see CONTRACTARIANISM; HOBBES; GAUTHIER, D). For example, killing might be proscribed because it is to everyone's mutual advantage not to have to worry about being killed. A problem for this view is that there may be some people in a society who contribute such a small amount to the society that there is no reason to co-operate with them. Indeed, some may contribute so little that there is not even any reason to refrain from killing them.

Another approach suggests that what seem to be claims about duties, e.g., that there is a duty to refrain from killing, actually are not claims at all. Since they are not claims, they cannot be either true or false. They are merely expressions of attitudes. For example, if someone says `we have a duty to help those in need', no claim is being made; the utterance is merely the expression of a positive attitude towards helping those in need. It is as if the person said `Hooray for helping others'. The main challenge for this view is to explain why much of moral conversation seems like reasoned argument. One strategy for dealing with this challenge is to argue that there is a logic of attitudes that mirrors the logic of claims or propositions (see EMOTIVISM; ANTI-REALISM; NONCOGNITIVISM).

In addition to the difficulties in giving an account of how we come to be subject to duties, the entire project of trying to characterize ethical concerns in terms of duties has come under criticism. One main objection is that the idea of duty is so closely connected to the idea of God as a lawmaker or imposer of duties that the concept has no place in secular philosophy (see ANSCOMBE, G E M). Another is that concentrating on duty blinds us to the rich diversity of considerations that are relevant to ethics. Instead of asking what our duties are, we should be asking how we should live (see VIRTUE; WILLIAMS, B).

Which of these views concerning duty will prevail? After only 2,500 years of work on these issues, it is still too early to tell.

See also:


Anscombe, 1958
Anscombe, G. E. M. (1958) `Modern moral philosophy', Philosophy 33: 1-19. (A powerful attack on the use of the concept of duty in secular philosophy)
Bennett, 1995
Bennett, J. (1995) The Act Itself, Oxford: Clarendon Press. (A discussion of the nature of action, including whether there is a morally significant difference between positive and negative actions.)
Frazier, 1995
Frazier, R. L. (1995) `Moral relevance and ceteris paribus principles', Ratio 8: 115-127. (A modern account of prima facie duties.)
Gauthier, 1986
Gauthier, D. (1986) Morals By Agreement, Oxford: Oxford University Press. (A modern defense of contractarianism.)
Gowans, 1987
Gowans, C. (ed.) (1987) Moral Dilemmas, Oxford: Oxford University Press. (A collection of articles concerning the possibility of moral dilemmas.)
Helm, 1981
Helm, P. (ed.) (1981) Divine Commands and Morality, Oxford: Oxford University Press. (A collection containing articles on the proposal that God imposes duties on us.)
Hobbes, 1651/1962
Hobbes, T. (1651/1962) Leviathan, London: Collins. (Ed. J. P. Plamenatz. The classic statement of contractarianism.)
Hume, 1740/1978
Hume, D. (1740/1978) Treatise of Human Nature, Oxford: Oxford University Press, 2nd edn. (Ed. L. A. Selby-Bigge. The classic account of the view that what seem to be moral claims are actually expressions of moral sentiments.)
Kant, 1753/1953
Kant, I. (1753/1953) Groundwork of the Metaphysic of Morals, in The Moral Law, trans. H. J. Paton, London: Hutchinson. (This classic work contains the argument that we impose duties on ourselves.)
Korsgaard, 1996
Korsgaard, C. M. (1996) The Sources of Normativity, Cambridge: Cambridge University Press. (A neo-Kantian account of the grounds of duty, with a good discussion of alternative proposals.)
Mackie, 1977
Mackie, J. L. (1977) Ethics: Inventing Right and Wrong, Harmondsworth: Penguin Books. (Contains a good introductory discussion of the problems with thinking that duty can be imposed on us by the nature of the universe.)
Sayre-McCord, 1988
Sayre-McCord, G. (ed.) (1988) Essays on Moral Realism, Ithaca: Cornell University Press. (A collection of articles concerning whether the nature of the universe can provide the grounds of duty. It contains a very good introductory chapter.)
Sinnott-Armstrong and Timmons, 1996
Sinnott-Armstrong, W. and Timmons, M. (eds.) (1996) Moral Knowledge?: New Readings in Moral Epistemology, Oxford: Oxford University Press. (A collection of articles on the possibility of moral knowledge, containing a very good annotated bibliography.)
Rawls, 1971
Rawls, J. (1971) A Theory of Justice, Cambridge, Mass.: The Belknap Press. (A very influential defense of a position which is an interesting combination of a contractarian and a neo-Kantian approach to ethics.)
Ross, 1930
Ross, W. D. (1930) The Right and the Good, Oxford: Oxford University Press. (The source of the notion of a prima facie duty.)
Thomson, 1990
Thomson, J. J. (1990) The Realm of Rights, Cambridge, Massachusetts: Harvard University Press. (Includes a discussion of the relationship between duties and rights, and a discussion of who (or what) can have rights and duties.)
White, 1984
White, A. R. (1984) Rights, Oxford: Clarendon Press. (Includes a discussion of the relationship between duties and rights, and a discussion of who (or what) can have rights and duties.)
Williams, 1985
Williams, B. (1985) Ethics and the Limits of Philosophy, Cambridge, Massachusetts: Harvard University Press. (A collection of articles supporting the view that duty based moral systems are not sensitive to a wide range of important ethical considerations.)
Zimmerman, 1996
Zimmerman, M. J. (1996) The Concept of Moral Obligation, Cambridge: Cambridge University Press. (A very general and comprehensive account of obligation (or duty), which gives close consideration to many of the topics discussed in this entry.)

Some of these items involve intricate argument but few are technical.

Robert L. Frazier