To be a moral agent involves the capacity to be morally responsible for what one does. An individual who is a moral agent has the capacity to incur moral responsibility for what he or she does. An individual can, therefore, stand to his or her actions in the relation of being morally responsible for them. Sometimes one's responsibility is of a positive or praiseworthy nature, and sometimes one's responsibility is negative or blameworthy in character. But one incurs a moral responsibility for a particular action just in case one stands in this relation to it.

Characterizing or describing this relation between an individual and his or her actions has received a great deal of attention by philosophers. Already in Aristotle one finds an attempt to explain precisely under what conditions moral responsibility is incurred, and one finds in Aristotle's discussion a treatment of remarkable sophistication. Recognizing that ignorance is a factor which can diminish or remove a persons moral responsibility, for example, Aristotle develops a set of criteria for determining which types of ignorance (and under which types of circumstance) can affect the determination of an agent's responsibility for the agent's actions. Thus, it was evident to philosophers from antiquity that a characterization of moral responsibility is a matter involving considerable complexities. Just as lawyers struggle to define in a precise manner the conditions under which individuals are to be judged legally responsible for their actions, and just as the articulation of these conditions involves a multiplicity of technical distinctions, so philosophers have labored in parallel fashion to define the conditions under which individuals are to be judged morally responsible for their actions.

What is notable about this rich tradition of philosophical investigation, at least the Western tradition, is its emphasis upon individual responsibility. Philosophers from Aristotle to the present for whom moral responsibility has been a significant concern have almost invariably concentrated upon the individuals responsibility for what he or she has done. Moral responsibility has been conceived almost entirely in terms of a relation between an individual and the individuals actions, or, alternatively, as a relation between an individual and states of affairs caused by the individuals actions.

The tradition has had very little to offer, therefore, by way of elucidating the concept of group responsibility. More precisely, the tradition has had very little to say about responsibility as a relation holding between groups and group actions, or, for that matter, as a relation holding between individuals and group actions (or states of affairs caused by these actions). This failure to take group responsibility seriously has not been due to a failure to acknowledge that groups can incur responsibility, nor that individuals can incur responsibility for group actions. On the contrary, people commonly ascribe moral responsibility to groups of individuals. But as an object of careful philosophical investigation, group responsibility has figured only minimally. There seems to have been little motivation among philosophers to undertake a philosophical elucidation of group responsibility and its special characteristics.

Philosophical discussions of moral responsibility, then, have concentrated almost entirely upon the responsibility of an individual moral agent for what the individual has done. Perhaps it can be argued that this concentration of emphasis has been due, at least in part, to there being less need traditionally for a precise understanding of group responsibility. In the less complex societies of the past there was perhaps less likelihood that the harms brought to people were the result of group or committee actions. In contemporary society, on the other hand, there is a much greater need to understand the dynamics of group responsibility. The complexities of decision making in modern institutions is an excellent case in point. Policy decisions in both the public and private sectors are increasingly designed and implemented by groups of individuals. It does not seem extravagant to claim that there has never been a greater need to understand the nature of group responsibility. As contemporary society becomes more complex, there seems to be more occasion to judge the moral status of group actions. Unlike the individual crooks, usurers, racketeers, and blackmailers of the past, those responsible for harms to society are often groups, and these are frequently groups operating in institutional settings. It is less likely in the contemporary scene that harms to society are found to be caused by persons acting alone.

Because the tradition has had little to offer by way of shedding light upon the intricacies of group responsibility it is common to find people confused about the ethical implications of their participation in group actions. According to what criteria should individuals be held responsible for the harm brought about by group actions? Here the tradition seems to offer little, and many people search in vain for clear moral guidance.

Suppose, for example, that a group of people under the supervision of Frank, a certain junior level manager, has presented a formal policy recommendation. The recommendation will automatically proceed to Franks' superior, unless Frank exercises his right to veto the recommendation. Suppose that he declines to veto it, it is subsequently approved and implemented by higher level officers, and it ultimately turns out to bring harm to innocent people, harm which was foreseen by Frank as probable. Who is responsible for this harm? Those who implement the recommendation? Those who give it final approval? Those who initially present it? Does Frank share in the responsibility by virtue of his inaction?

It might appear relatively evident that the responsibility for the final outcome is shared by all of these individuals. However, it is not at all evident that the responsibility for the final outcome is shared equally by them. But if it is not shared equally by them, how is it distributed among them? Is one to judge Frank only minimally responsible in comparison with those who give the recommendation final approval? And how should one compare the responsibility of those who initially present the recommendation with those who give it final approval? How is one to tell? According to what principles is group responsibility distributed among the moral agents who share in it?

Imagine Frank in the process of deciding whether or not to exercise his veto power. Since his department has invested substantial resources in the work of the study committee, there is considerable pressure on him to allow the recommendation to proceed to his superiors. Yet Frank is aware of the potential effects of the recommendation's implementation, and he is aware that inaction on his part makes him a participant in the series of events leading up to the final outcome. But to what extent is he a participant, and to what extent does he share in the responsibility for the final outcome? It is not clear how to arrive at straightforward answers to these questions. Again, these are issues which have seldom been addressed by philosophers. With little difficulty, of course, Frank can learn to what extent he is legally culpable for his inaction by consulting various legal documents. But if Frank is likewise concerned about the extent to which he is morally responsible for the final outcome, how is he to arrive at an answer? In vain will he search to discover philosophical documents of a similar nature capable of offering him genuine guidance.

In spite of the predicament of Frank and many others like him, it should nevertheless be noted that in recent years philosophers have begun addressing issues relevant to group responsibility with an intensity of more than modest proportions. No doubt some of this recent activity has been inspired by Joel Feinberg's classic 1968 paper, 'Collective Responsibility', or a 1971 anthology, Individual and Collective Responsibility: The Massacre at Mai Lai (edited by Peter A. French).¹ l And while Frank may find scarcely more straightforward advice now than twenty years ago, I believe that a clearer understanding of the issues surrounding the concept of group responsibility has been in the process of evolving in recent years. Recent contributions by Virginia Held and Stanley Bates, for example, have helped to clarify what is to count as a group by exploring the conditions under which a random collection of individuals can incur responsibility.² The assignment of responsibility in cases where the members of a group perform actions serially has received significant clarification by Michael J. Zimmerman.³ And Törbjörn Tannsjö has explored the relationship between group actions and the consequences of these actions by virtue of which group actions are judged responsible.⁴

The account of moral responsibility I shall appeal to is, broadly speaking, that of the Aristotelian tradition (as explicated by commentators such as W.D. Ross). I shall assume that something along the lines of such an account is correct, and, based upon this account, the present volume is an attempt to contribute to this process of clarifying the concept of group moral responsibility and the key issues surrounding it. As the title makes clear, the central theme by means of which I attempt to unify the various parts of the discussion is that of shared moral responsibility. When a group of persons is responsible for what happens as the result of their actions, the persons can be said to share responsibility for the outcome of their actions. The concept of shared responsibility is reasonably familiar in ordinary discourse. It is not uncommon for people to judge that certain elected officials share responsibility for the misuse of public funds or that various employees of a large corporation share responsibility for flaws in products it manufactures. Parents are sometimes said to share responsibility for the effects of their child's actions, and the citizens of a community are sometimes said to share responsibility for its substandard schools, high crime rate, or intolerable highways. In Chapter Two I introduce a precise characterization of this concept, and I attempt to do so in such a way as to accord reasonably well with ordinary usage.

One of the central questions I shall confront with regard to the concept of shared responsibility is the following: Which factors do, and which factors do not, influence or affect the degrees to which the individuals sharing responsibility for a state of affairs turn out to bear or incur responsibility for the state of affairs? If several persons share responsibility for what happens as a result of what they have done, what are the factors which affect the degree to which each of the persons is responsible for the outcome? Which factors, for example, have an effect upon Frank's responsibility for the harm resulting from the implementation of the recommendation? And how would the degree of Frank's responsibility differ if certain things had been different in the course of events leading up to the final outcome?

It might be observed that certain presuppositions are made in the very way these questions are formulated. They presuppose, for example, that individuals can be morally responsible for what happens as the result of group actions. To some it might seen intuitively obvious that individuals can incur moral responsibility in this manner, but this point is by no means unanimously recognized by philosophers. Gerald Massey, for example, believes that if Frank and another individual were to perform an action such as a bank robbery, then the bank robbery is performed neither by Frank nor by the other individual but by their "sum individual". Accordingly, neither individual incurs responsibility for the bank robbery; the responsibility is incurred by their sum individual. To judge that Frank as an individual incurs responsibility for the bank robbery is, according to Massey, to make manifest the "unigrade bias of philosophy."⁵ John Ladd likewise has difficulty with the idea that a person such as Frank can bear individual responsibility for what his organization has brought about. Provided that Frank is not acting contrary to the goals and principles of his organization, his individual contribution to the outcome becomes swallowed up in the corporate action. He himself can bear no moral responsibility for the effects of the corporate action.

The questions raised above make another presupposition concerning the nature of moral responsibility. They presuppose that moral responsibility can come in degrees. Depending upon the nature of one's involvement in the sequence of events leading up to a state of affairs, one can bear differing degrees of responsibility for the state of affairs. Moreover, two different people can bear differing degrees of responsibility for the same state of affairs. Philosophers (Nozick,⁶ for example) have commonly spoken of moral responsibility in this manner, but to others it might not be evident that responsibility comes in degrees. At least it is not self-evident that this is the case, and it will be necessary to address this point in the following discussion.

Third, the questions presuppose that responsibility is a two-place relation between a moral agent, or a group of moral agents, on the one hand, and a state of affairs on the other. More will be said later about the states of affairs for which agents are responsible. But it is important to bear in mind that responsibility is sometimes described in ordinary language as if it were a three-place relation. For as moral agents we are often said to be responsible to other moral agents for what has happened or for what ought to happen in the future. A corrupt mayor might be judged responsible to the citizens of his community for his misdeeds, and some moralists speak of agents as being responsible to God for what they have done during the entire course of their lives. One can conceivably have responsibilities to political and social institutions such as governments, corporations, labor unions, ecclesiastical organizations, and the estates of deceased persons, in a manner which is not reducible to responsibilities to individuals. Even animals are sometimes judged to be the objects of our responsibilities. The treatment of moral responsibility in what follows should not be taken as a refusal to acknowledge that agents are often responsible to other agents, God, animals, or whatever. Nevertheless, the discussion will be limited to a treatment of the moral responsibility agents bear for states of affairs.

In much the same way the discussion will not directly apply to situations in ordinary discourse in which moral responsibility constitutes a two-place relation between persons and other persons or between persons and objects. It is often said that someone is responsible for another person or that someone is responsible for an object in his or her possession. I am responsible for the book I borrowed from another and subsequently loaned to a third party, for example. But since moral responsibility is here construed as a relation between persons and states of affairs, cases of this type do not directly fall within the scope of the present discussion.

One can, of course, frequently construe such cases as relations between persons and states of affairs. If I am responsible for the book I borrowed from another person, then I presumably have a responsibility to bring about the state of affairs that your book is returned to you. My responsibility for the book can be described in terms of a responsibility to see to it that a certain state of affairs eventually obtains. If I bring about this state of affairs, I will no longer have the responsibility for the book I borrowed from you.

I further presuppose, in raising the question under consideration, that agents can share responsibility with other agents for a state of affairs without knowing or realizing that they do so. And this is so even if it is assumed that they are aware of their own responsibility for the state of affairs. It is possible, as I understand the concept of shared responsibility, that an agent share responsibility with other agents for a state of affairs without realizing that the other agents are involved in the sequence of events leading up to its occurrence. One might be aware that he or she bears responsibility for a state of affairs and fail to realize that others bear responsibility for it. Such might be the case, for example, if two women attempt to poison the same victim at the same meal, and neither is aware of the other's involvement. Both are responsible for the poisoning, but neither is aware that she shares responsibility for the poisoning with another.

Likewise, it is possible that agents who have no familiarity with the concept of sharing responsibility or agents who are unable to grasp the concept are nevertheless capable of sharing responsibility. In certain societies the concept of sharing responsibility might never have occurred to its inhabitants (indeed, the same might be true of the concept of responsibility itself), but those of us for whom the concept is familiar might have good reason to say of them that they share responsibility for what they have brought about. To say of several agents that they share responsibility for a state of affairs, therefore, is by no means to imply that they knowingly share responsibility. It is perfectly possible that none of them possesses this knowledge.

In many situations, finally, responsibility is ascribed to non-human entities. While these non-human entities sometimes contain or are composed of human agents, as when corporations are said to be responsible for harms to certain people, this is not always the case. Storms, animals, plants, and rocks are sometimes said to be responsible for what happens, whether harmful or beneficial from the point of view of human beings. And even immaterial entities, such as evolution, chance, or fate, are ascribed responsibility for various states of affairs.

In the ensuing discussion, with the exception of brief sections in the second and last chapters, my remarks will be confined to responsibility borne by human agents. Thus, I shall speak of shared responsibility only in terms of responsibility which is shared by two or more human agents. While I do not wish to deny that in some sense, for example, two corporations can share responsibility for a dangerously defective product, the concept of shared responsibility I propose to examine should not automatically be assumed to apply to humans and non-humans alike. The conclusions I draw about group or shared responsibility pertain strictly to situations in which human beings share moral responsibility.

The concept of group responsibility I distinguish in the next chapter from that of collective responsibility. A group is responsible for a state of affairs, as I characterize the notion, if and only if each member of the group bears at least some degree of responsibility for the state of affairs. A collective, on the other hand, can be responsible for a state of affairs even if no member of the collective, or only some of the members, bears responsibility for it. In Chapter Two the concept of group responsibility is likewise distinguished from the responsibility incurred by formal organizations such as corporations and military institutions. Such organizations employ people, and they are sometimes said to consist of these people, but they are obviously much more than simply groups of people. Nevertheless, I urge that these people can incur responsibility for the same states of affairs as the responsibility incurred by the organization itself. In this context I attempt to call into question two lines of argument employed by John Ladd for the conclusion that an individual acting on behalf of a formal organization incurs no personal responsibility for what happens.

The heart of the discussion revolves around the question which factors do, and which factors do not, affect the degree to which an individual bears responsibility for a state of affairs when the responsibility is shared with others. In Chapter Three it is argued that there are at least three factors which possess this capability. They are the agent's motives, the nature of the agent's contributing action, and the circumstances surrounding the performance of the contributing action (it does not appear, however, that the last of these can be the sole factor determining the degree to which the agent bears responsibility).

Chapters Four and Five concern the question whether the fact that others are likewise responsible for a state of affairs should be thought, as it frequently is, to have a diluting effect upon the degree to which an individual is responsible for the state of affairs. In Chapter Four several versions of this view are presented and examined, and in Chapter Five I present and defend an alternative, anti-dilutionist view, arguing that it is more plausible than any of the versions of dilutionism. In this connection I urge that it is a common error to think of shared responsibility as analogous to a pie, where one's share of the responsibility for what happens diminishes as the number of those sharing responsibility increases. I also suggest that, whereas the mere fact that others share responsibility for the same state of affairs cannot dilute the degree of one's responsibility for it, nevertheless there are sometimes extenuating circumstances, connected to the fact that others share the responsibility, which do possess this diluting capability. The reality of such circumstances can easily lead one to embrace dilutionism, but it is crucial to see that dilutionism is not a consequence or entailment of this fact.

Another factor which is sometimes thought to affect the degree to which one is responsible for a state of affairs is the location of one's contributing action in a temporal sequence of actions by other agents. In particular, if one's action triggers the threshold, then it is tempting to suppose that one is more responsible for the relevant outcome than if one's action had been performed earlier in the sequence. In Chapter Six no plausible basis for this view is found. However, in the presence of certain accompanying circumstances, a person whose action triggers the threshold can turn out to bear more responsibility than otherwise. It is sometimes thought, in addition, that an agent whose action is performed after the threshold has already been crossed bears no responsibility for the outcome. With certain qualifications I endorse this view; however, such an agent can still bear responsibility for having performed an action intended to bring about or contribute to an outcome whose occurrence is not known to have already been made inevitable.

Chapter Seven concerns still another factor which is sometimes thought to affect the degree of one's responsibility: the degree of risk one knowingly takes that the outcome will occur. Like intention, recklessness and negligence are regarded by the law as varying degrees of mens rea, and accordingly a reckless or negligent risk taker is sometimes thought to bear a greater responsibility for the occurrence of the risked outcome than one taking a risk of modest proportions. This view, I suggest, can be contrasted with what I call the indiscernibilist view, according to which the degree of risk one knowingly takes has no effect upon the degree of one's responsibility for the risked outcome. However, there are strong and weak versions of indiscernibilism, and I argue that its weaker version emerges in the end as the most attractive of the views under consideration. Thus, I reject the account of the relation between risk and responsibility as it is sometimes popularly characterized.

Having surveyed a number of factors which do, and a number of factors which do not, affect the degree to which individuals bear responsibility when it is shared with others, Chapter Eight takes up the question under which conditions such agents are fully responsible for what happens. It is commonly said of people that they are fully responsible for what happens, even when their responsibility is shared with others. After looking at one criterion which is too weak and another which is too strong, I propose a criterion for one's being fully responsibility which seems correctly to capture the essentials of the concept. Finally, Chapter Nine examines the nature of shared prospective responsibility. I argue that agents can share responsibility to contribute to future states of affairs. But, contrary to the way many speak about prospective responsibility, agents cannot share responsibility to bring about future states of affairs.