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Ethics, History of: Other Developments in Twentieth-Century Ethics


Even setting aside the rich interplay between naturalism, nonnaturalism, and noncognitivism that is one of the hallmarks of twentieth-century moral philosophy, a very rich history remains, one that is impossible to even fully summarize here. Much of the story may be found elsewhere in the present volume in discussions devoted to particular moral theories and philosophers. The present entry examines just a few of the many themes that have occupied the attention of moral philosophers working within a diversity of traditions and that have thus exercised substantial influence on the shape of moral philosophy in the twentieth century.

Moral Principles

Whether the number of principles governing right conduct is one, or several, or even indefinitely many is a question that has animated the development of moral philosophy over the past century. Of course, this is by no means a new problem for moral philosophy, and the responses found to it in the twentieth century are themselves shaped by earlier debates between the nineteenth-century utilitarians and their intuitionist and idealist opponents.

Indeed, the ideal utilitarianism developed in George Edward Moore's Principia Ethica (1903) can usefully be seen as a possible rapprochement between utilitarianism and more pluralistic views. Moore maintained that there was but one ultimate principle of duty that one should act so as to promote as much good (intrinsic value) as possible, and in Principia, he maintained this principle to be analytic. It is puzzling that Moore did not take his own Open Question Argument to tell against this identity claim, but setting that aside, Moore appears to be an arch-monist about ultimate principles of right action.

If we take note of Moore's innovative and influential value theory, however, it becomes clear that Moore is in a position (assuming his view is otherwise sustainable) to accommodate many of the insights of pluralists. Two aspects of Moore's value theory are critical. First, Moore held that goodness (or intrinsic value) is not identical to any natural property. Consequently, the bearers of intrinsic value may form an ultimately heterogenous group, having nothing salient in common other than their goodness. Indeed, Moore is a pluralist about the bearers of intrinsic value. Second, Moore argued that the value of a whole need not be the same as the value of the sum of its parts; such wholes are organic unities.

This pluralism about the bearers of intrinsic value and the flexibility that the doctrine of organic unities affords when it comes to the value of a whole, yield a view that seems well poised to accommodate the concerns of pluralists about ultimate principles. For pluralists have long emphasized that there are seemingly many potential grounds of duty and have challenged utilitarians to show that their view could leave in tact the seeming legitimacy of many moral rules that are not directly concerned with promoting utility. For the consequentialist who identifies goodness with a specific natural property and denies the doctrine of organic unities, these are very difficult challenges to meet. For one must then show that the apparently diverse grounds of duty really all involve the (naturalistically construed) property of goodness or else explain away the appearances. And one must show that apparently legitimate moral rules (e.g., rules governing the keeping of promises) really do serve to promote goodness. To a consequentialist of Moore's stripe, however, it is always open to identify further bearers of intrinsic value to accommodate our intuitions about the diverse grounds of duty and to appeal to the doctrine of organic unities to maintain the legitimacy of accepted moral rules even when these seem to lead to a universe with very disvaluable parts. Indeed, it may seem that provided a sufficiently flexible theory of value, the determined consequentialist will be able to say just about anything when it comes to duty.

Shortly, Moore's consequentialism was subjected to influential critique by William David Ross. Where earlier pluralists had identified many principles of (all things considered) duty, in The Right and the Good (1930), Ross sought principles of prima facie duty. For Ross, prima facie duties were acts of a type that tend to be our duty all things considered. Moreover, if someone had a prima facie duty to wash his neighbor's car (say because he had promised to do so), then this would be an all-things-considered duty if it did not pose any conflict with other prima facie duties. Ross argued forcefully that our apprehension of certain kinds of acts as prima facie duties does not depend upon our apprehension of them as being productive of more rather than less good.

In most, or perhaps all, cases, however, an agent will have conflicting prima facie duties. How is one to determine what duty requires, all things considered? To this, Ross answered that there are no principles (or at least no principles we have any prospect of identifying and using) that would determine the answer to this question, and that the best one can do is to exercise good judgment regarding which prima facie duty is, in the circumstances, most weighty. In taking this position, Ross appears to avoid an influential argument for monism about ultimate principles to which John Stuart Mill had given powerful voice in his System of Logic (1843/1874). Mill had argued that there could only be one possible ultimate moral principle because any set of several principles were liable to conflict about a given case, and there would need to be a higher principle to be an umpire between them. By construing principles as principles of prima facie duty and by denying that there are any principles determining final duty, Ross seems to sidestep Mill's argument.

At the same time, Ross cast serious doubt on whether the systematic advantages often credited to monism about principles (especially by the nineteenth-century hedonistic utilitarians) could really survive the death of naturalistic accounts of the good, a death that Moore's arguments were at the time widely held to have confirmed. Ross recognized that some may be dissatisfied that a system of prima facie duties leaves no clear method for determining final duty. Ross plausibly replied that his view was no worse off in this regard than was the ideal utilitarianism of Moore. While Ross's view provides no discernible method for determining which of several prima facie duties is most weighty, Moore's view provides no discernible method for determining which of the various goods (as well as combinations thereof) that we might produce through our action have the greatest intrinsic value. One consequence of this debate between Moore and Ross was that the debate between monists and pluralists was revealed to depend critically on views of value and moral conflict.

Despite Ross's influential case for pluralism, the two dominant normative theories of the twentieth century, utilitarianism and Kantian deontology, both hold that there is only one ultimate principle of duty though, of course, they disagree about what this principle is. A perennial challenge for such views is to explain and or to justify the seeming legitimacy of a diverse set of common moral rules. It is worth looking briefly, then, at some of the resources developed by principle monists to meet this challenge.

For the principle monist, it is critical to define some relationship between whatever principle is taken to be ultimate and more particular midlevel moral rules, such as rules against promise-breaking or against dishonesty. One possibility, discussed influentially by John Rawls in "Two Concepts of Rules" (1955) is that some rules might be constitutive of a practice while other rules serve to justify that rule-constituted practice. Thus, Rawls imagines that a utilitarian might use a consequentialist principle to justify a practice of punishment that is itself constituted by backward-looking retributive rules. For example, a practice of punishment might be constituted in part by a rule that only those who have committed a crime are to be punished (no matter how much good punishing an innocent might do) even while the practice is justified by the good it brings about. Despite what the example of punishment might seem to suggest, this distinction does not entail that the only apt justifications of rule-constituted practices are consequentialist ones. Indeed, a Kantian could claim that the justification for a practice is that it best expresses respect for the dignity of each person even while that practice is constituted by rules that do not directly concern the dignity of persons. Rawls was quick to emphasize that his distinction was not a new one. Nevertheless, his clear and forceful discussion of it led moral philosophers to more steadfastly distinguish different levels of justification.

The latter half of the twentieth century saw the careful development of a variety of views about the relationship between ultimate standards and the more particular and diverse moral rules familiar from everyday life. Many of these developments were advanced by consequentialists. One influential view was put forward by Richard M. Hare in Moral Thinking (1981). According to Hare, there are two distinct levels of moral thinking. One, which Hare called intuitive moral thinking, involves the deployment of familiar and relatively simple moral principles in deciding how to act.

Hare claimed that intuitive moral thinking is characterized by a plurality of such principles and that such principles can conflict with one another by recommending different and incompatible courses of action. When this occurs, Hare argued, we can ascend to critical moral thinking. Doing so requires deploying a superior principle (for Hare, a version of the principle of utility). This principle is capable of both adjudicating the conflict between rival principles at the intuitive level and (in conjunction with facts about human psychology) justifying our everyday use of intuitive moral thinking. For example, instead of trying to determine which of two conflicting intuitive principles is more weighty (as Ross advocated), we can ask directly what course of action would best satisfy the utilitarian principle. Nevertheless, our everyday use of intuitive principles is justified because (for agents like us) directly applying the principle of utility to all of our decisions would be cumbersome, costly, and error prone.

Importantly, Hare's two-level view of the relationship between the principle of utility and more particular moral principles differs from classic versions of rule utilitarianism as well as from other forms of indirect utilitarianism. On the rule utilitarian view, the rightness of an act is defined in terms of its conformity to the best (i.e., best at promoting good consequences) rules whereas for Hare, it is possible both for an act to be in conformity with intuitive principles and yet wrong as well as for an act to be violative of intuitive rules and yet right. Rightness is determined by the principle governing critical moral thinking.

The resources of Hare's view can be deployed not only in considering familiar moral rules, but also in considering qualities of character. For just as the principle of utility might recommend the adoption of a range of more or less simple moral rules, so, too, it might recommend the cultivation of useful character traits. Again, though, one must be careful to distinguish what principle is actually the standard of rightness or duty. For some philosophers, such as Peter Railton, the act-consequentialist principle remains the ultimate moral standard even while it recommends that we develop the kinds of character traits that will sometimes lead us to act contrary to it. Others, however, suggest that the proper way for the utilitarian to evaluate acts is by reference to the motive that leads an agent to act with motives being evaluated by reference to their consequences.

Not surprisingly, the increased attention to indirect and two-level versions of principle monism also spawned more careful criticisms. In the case of indirect theories such as rule utilitarianism, one important worrynicely and influentially discussed by David Lyons (1935) in Forms and Limits of Utilitarianism (1965)has been that such views inevitably collapse into their more direct progenitors. In the case of rule utilitarianism, for example, the collapse supposedly occurs because the really best rules would recommend the very same choices and actions as would a direct application of the principle of utility. In the case of two-level theories, an important set of worries has concerned the stability of the view. Some philosophers worry whether human beings really can smoothly ride the escalator between intuitive and critical thinking more or less as circumstances warrant.

In other cases the worry is more conceptual. For if (as Hare's view seems to require) it is sometimes advisable to set aside the ultimately correct standard, then it seems possible that there could be circumstances in which it is advisable to permanently set aside (or even to banish from thought entirely) the putatively correct standard. Whether a proper standard of conduct could be self-effacing (to borrow a term from Derek Parfit's influential discussion in Reasons and Persons [1984]), has been a matter of intense dispute, especially with regard to moral standards. Some, following philosophers such as Henry Sidgwick, welcome the possibility; others see in it a deep confusion. In some cases the thought has been that moral standards are essentially deliberative tools and so must have some place in the psychology of moral agents. In other cases the thought has been that moral standards essentially play a role in interpersonal relations and so must remain public, where they can be appealed to, criticized, and defended.

Despite the development of new tools to defend principle monism, the last quarter of the twentieth century saw a notable (and ongoing) revival of pluralism, sometimes of a new and more radical variety. Some of this interest centered on the ways in which various values might conflict. Where Ross was cautiously skeptical of identifying principles that would systematically rank prima facie duties, some philosophers, such as Thomas Nagel (1970), began to argue that various values might be fundamentally incommensurable, perhaps because they arise or make sense only within certain standpoints or perspectives. Clearly incommensurable values would seriously complicate the prospects for reasoned and justified choice when such values conflict, and there is no general agreement on whether it would remain possible at all.

But the revival of interest in pluralism has also been inspired by careful reflection on the sheer variety of considerations that can acquire moral significance. Where Ross had countenanced a limited set of principles governing prima facie (but not final) duty, a new breed of pluralists (sometimes called particularists) seek to challenge whether there are any moral principles at allor at least whether a proper understanding of morality must make reference to them. On such views our moral understanding is not best represented as the application of universal rules but, rather, should be seen as kind of direct appreciation of the moral relevance of the particular features before us. The advantages and liabilities of this position are still being explored and debated.

Moral and Personal Value

According to a dominant view of moral value, what is of moral value should be an object of care and concern for any rational agent. This view goes back at least to Plato, and according to it, moral value is of universal appeal; one has reason to care about it no matter who one is. Though widely held this view raises a number of important questions, in part because there seem to be many values that do not necessarily have a claim on any rational person. We might call such values personal values to denote that whether (or perhaps how) one ought to care about them depends upon what sort of person one is. Such values are also commonly referred to as nonmoral values. Among the most commonly offered examples are the value we find in personal relationships, such as the value of one friend to another, the value of achieving a personal goal or project such as the goal of amassing the world's most comprehensive collection of glass paperweights, and the value of living up to a personal ideal such as being a good marine or a good writer.

It is now widely agreed that such personal values need not be self-interested in any intuitive sense since a person's projects and concerns might be directed outward to others and to the world. Intuitively, the person whose project is to save land for a bird sanctuary is working to benefit the birds or the environment and not, at least in the first instance, herself. It is often thought that personal values depend upon the particular relationship in which a person stands to the object of value (as the value a parent finds in their child may depend on it being their child) or upon the particular preferences or choices the person has made (amassing those paperweights may be of importance only because the agent has come, perhaps by choice, to care about doing so).

If we accept some distinction between moral and personal value, then a number of issues arise. Since distinguishing moral and personal value raises the possibility of their coming into conflict, one must wonder whether they really do so. One view, associated with Immanuel Kant, is that personal values cease to be of value if ever their pursuit runs afoul of moral value. Consistent with this, though, one might hold that moral values themselves must make room for the pursuit of nonmoral ends and that our understanding of what moral value requires of us should be shaped by our intuitions about the reasonable pursuit of other values. Then there is the possibility that there is a genuine conflict between moral and personal values, and this raises questions about what the appropriate response to such a conflict would be. Before turning to these issues in more depth, however, it is worth pausing to ask whether they might be sidestepped.

Given the immense energy devoted to understanding the relationship between moral and personal value, it is notable that the twentieth century opened with a classic rejection of the problem. Moore argued that the tendency to distinguish moral and personal value rested on confusion and that in fact there is no such thing as personal value. Though couched as an argument against egoism, Moore's reasoning, if sound, would undermine the possibility of something being valuable to me but not to others. For Moore held that any putative claim of the form X is good for A must be resolved into a claim of absolute value (either into the claim that X is absolutely good and so in having X, A would have something absolutely good or else into the claim that it is absolutely good that A have X ) or else into a psychological claim, such as the claim that A desires X, which Moore argues is not really a value claim at all. To be sure, Moore did not deny that many of the supposed examples of personal value are in fact valuable (if anything, he emphasized their value), but he argued that properly understood, such value must be absolute and so equally of value from any point of view. Few now accept Moore's argument or its conclusion. For a representative criticism see John Leslie Mackie's "Sidgwick's Pessimism" (1976); for a more recent defense of an argument that is similar in spirit to Moore's, see Brian Medlin's (19272004) "Ultimate Principles and Ethical Egoism" (1957).

Setting Moore's position aside, there remain a host of questions about the relationship between moral and personal value. During the heyday of Ross and his fellow intuitionists, these questions received comparatively less attention. But as Rossian pluralism receded from center stage and utilitarianism and Kantian ethics (and later virtue ethics) began to be perceived as the main alternatives, the relationship between moral and personal value became a central topic of debate for moral philosophers.

According to one influential critique initiated by Bernard Williams, some moral theories fail precisely because they do not give a proper place to personal values. In his "Critique of Utilitarianism" (1973), Williams charged that utilitarianism requires agents, in so far as they take up a moral point of view, to regard their own projects and values as of no greater importance than the values and projects of others. Indeed, the value of anyone achieving their personal aims depends not at all on whose aims they are but on what contribution they make to the overall amount of happiness in the world. However, having personal values in the first place seems to presuppose attaching some significant importance to them, and such values are part of what make us who we are.

The problem, Williams charged, is not that utilitarianism implies implausible moral verdicts but that it leaves us thinking about matters in the wrong way. And if utilitarianism asks us to treat our own values and projects as having no greater importance than anyone else's, then, as Williams put it, it amounts to an assault on our psychological health, on our integrity. Though officially directed at utilitarianism, Williams's argument was more broadly influential. It inspired further close attention to the character and variety of personal values and to the ways in which they are an essential element of any familiar picture of human life and agency. Some philosophers were also quick to attempt to extend Williams's point to moral theories other than utilitarianism and to take his critique to undermine any normative theory that embodied a very strict impartiality.

As moral philosophers gave greater attention to personal values in the 1970s and 1980s, there was at the same time a great increase in the moral discussion of concrete moral problems. None received greater attention than the grave problem of hunger and poverty. In light of these developments, a new interest in the demandingness of morality arose. It is important to distinguish the issue of demandingness from the question whether moral requirements represent categorical or hypothetical imperatives. While the latter is a matter of whether moral requirements represent actions as good (or bad) in virtue of the ends that may be brought about by acting on them, the former is a matter of the imposition that complying with morality makes upon the other interests and concerns of the agent. A moral requirement might be categorical (requiring an agent to perform certain actions whether they serve certain purposes or not ) and yet still not be very demanding if complying with it would not frequently or profoundly interfere with an agent pursuing other aims. Conversely, an imperative might be hypothetical and still be very demanding. While the question of whether moral requirements represent categorical or hypothetical imperatives is a matter, in some sense, of the logic of moral requirements, the demandingness of moral requirements depends crucially upon both the content of moral requirements and also upon contingent facts about the aims of the agents to whom moral requirements apply, and also the state of the world.

Demandingness has come to be such an important issue, in part because, given the state of the world, it seems likely that virtually any plausible moral theory threatens to be extremely demanding. While this may be obvious in the case of utilitarianism, it may be no less true of any moral theory that recognizes a duty to aid others in need, as virtually any plausible view must do. As philosophers such as Peter Singer in his famous paper "Famine, Affluence, and Morality" (1972) have emphasized, most people in developed countries, even those of modest means, are in a position to take actions that would save the lives of many other people simply by sacrificing what in the light of comparison seem like trivial personal goods. And yet there is no obvious stopping point to this argument, and if there is not, then morality might require us to sacrifice nearly everythingat least until circumstances change and our aid is no longer needed (which is unlikely to say the least!).

Philosophers have explored various responses to the issue of demandingness. Three will be noted here. First, for some, the problem is not with any account of morality that leaves morality demanding. Morality simply is demandingor at least can be in a world such as oursand if people are often unwilling to do what morality requires, this is because they do not care as much as they should about morality. As an alternative to such rigorism, many philosophers have argued that theories of morality that leave morality highly demanding are dubious for that reason. The task is then to find a plausible revision. In the case of our duties to the needy, some have suggested that those duties are less stringent when those in need are far away and unfamiliar. Others suggest that morality requires us only to do our fair share of the helping, even if this leaves many of those in desperate need without help at all. Still others argue that our duty to aid, especially when applied to those in faraway lands, is a collective not an individual one.

A third approach is to argue that morality may be very demanding but that morality should not be the sole or even dominating concern of a good person. On this view our ideal of a person is of one whose concern with morality is itself tempered by other (possibly conflicting) concerns. This last possibility shows further that the issue of demandingness must be distinguished from the question of whether moral demands are overriding. Just as a job might be very demanding even while only a fool would allow its demands always to override other concerns, so, too, some suspect that morality might be highly demanding but that one can also give it too high a place in one's life.

Though the view that moral value has a claim on all rational agents has been a dominant one, it has also been subjected to interesting and influential critique. In the first half of the twentieth century, much effort was made to understand what attitude is involved in the judgment that something is of moral value. Under the influence of Moore's Open Question Argument and along with the rise of the early noncognitivists, it was often thought that virtually anything could be coherently judged to have moral value. After all, if (as Moore held) moral value is not identical to any natural property, or (as the early noncognitivists maintained) to hold something to have moral value is just to take a special favorable attitude towards it, then there seems to be no conceptual bar to holding virtually anything to have moral value. In the latter half of the twentieth century, however, following the lead of philosophers such as Philippa Foot and Gertrude Elizabeth Margaret Anscombe, many moral theorists began to think that there was a necessary connection between judgments of moral value and particular human concerns. To claim, for example, that painting two of one's toenails green is morally good is, philosophers such as Foot argued, simply unintelligible (absent some special background story) since doing so has no discernible connection to human flourishing or well being.

Once philosophers began to look to the possibility that there might be a necessary connection between moral evaluation and specific human concerns and interests, they also began to look carefully at evaluative concepts that seem clearly to implicate such a connection, such as specific virtue concepts like courage and modesty. Where the first half of the twentieth century was dominated by discussion of ethical concepts such as good and right (sometimes called thin ethical concepts), the latter half of the century saw steadily increasing interest in thick ethical concepts, such as virtue concepts, that single out specific forms of action and practical orientation as worthy of esteem.

To think that moral evaluation must somehow be directed at specific human concerns and interests is clearly consistent with the possibility that the relevant concerns are (or at least can be) universally the concerns of any rational being. Thus, one might suppose that in seeing courage as a moral value one must suppose that it is worthy of the esteem of any rational agent. As the century progressed, however, philosophers such as Alasdair MacIntyre (1981) and Williams began to argue that the very way in which we make moral or ethical evaluations is shaped by particular institutions and practicesby what we might call culture. And since these differ from place to place and time to time, it is not clear that all rational agents must even share a mode of evaluation, much less that there is some thing (moral value ) with which all rational beings should be concerned. Indeed, for such philosophers, the very idea that moral value is that value which has a claim on any rational being is itself a (dubious) product of Enlightenment culture, with Kant receiving a large share of blame. Though such philosophers are not skeptical about moral value, they are denying a particular way of demarcating moral value from supposedly other values. If such philosophers are correct, moral values would seem to have some of the hallmarks commonly associated with personal values: they depend upon the particular position and concerns of agents.


It is scarcely possible to imagine a moral theory that does not depend upon claims about the nature of human or rational agency, but the degree to which moral philosophers actively look to accounts of agency in developing and defending normative theories fluctuates over time. Philosophers such as David Hume and Kant based their moral philosophy on sophisticated and original accounts of agency. By contrast, the beginning of the twentieth century saw a comparative neglect of agency. At least two factors may provide a partial explanation.

The first is that the early intuitionists, beginning with Moore, were highly interested in human agents as knowers of moral propositions or facts. If moral propositions were intuitive or self-evident, then the serious and difficult question became how human beings have such knowledge. On the surface this does not preclude a deep interest in agency (perhaps, in a Kantian vein, human beings know about the moral necessity of certain acts by knowing something about human agency). But the surrounding philosophical climate tended to eclipse this alternative. The nineteenth century saw the rapid and exciting development of psychology as an empirical science. Add to this the fact that Moore's Open Question Argument made it seem scandalous even to appear to derive moral conclusions from empirical observation. But if human agency is ultimately a matter of psychology and psychology is a matter to be settled by empirical methods, then the intuitive moral knowledge the intuitionists attributed to human beings could not be based upon knowledge of agency lest the dreaded naturalistic fallacy be committed. The second factor that may partially explain philosopher's relative neglect of agency is the fact that philosophers were busy looking elsewhere, especially to linguistic phenomena.

The latter part of the twentieth century, however, saw renewed and intense interest in the integration of normative theories with theories of agency. In part, this may be traced to the rise of Kantian ethics that treats moral principles as principles of rational willing. It was also no doubt influenced by the rise of action theory in the latter half of the twentieth century as well as by the renewed interest philosophers showed in problems of personal identity and by exciting work done on the issue of free will. All of these developments had the effect of drawing attention to human beings as actors with values, ideals, beliefs, emotions, evolving desires and interests, plans, habits, addictions, and more. This is quite different from looking to human beings as perceivers of value.

It is not possible to summarize all of the ways in which moral philosophy has been impacted by its renewed and increasing attention to agency. One important theme concerns the possible analogy between the interest agents are rational to take in their own future concerns and the interest agents are morally required to take in the concerns of others. We think of agents as unified across time. To reprise an example of Nagel's: If I expect that I will want to eat a persimmon next week, then I will be concerned to take the steps necessary to make this possible (even if I do not now care whether I eat a persimmon next week or care whether I come to want to eat a persimmon next week). Indeed, the ability to integrate one's desires and concerns this way is considered a hallmark of prudential rationality. In The Possibility of Altruism (1970), Nagel argued that, properly understood, vindicating the rationality of caring about the interests of your own future self also shows how one may vindicate the rationality of caring about the interests of others. Though he later abandoned this argument, Nagel's effort to integrate the justification of important moral norms with an account of an agent as a person persisting through time and potentially aware of other persons and their interests was of lasting importance. Philosophers such as Parfit, as well as Nagel himself, continued to develop these themes.

One such development was an increased attention to a distinction, first introduced by Nagel, between agent relative and agent neutral reasons. Though the proper way of drawing the distinction is a difficult technical matter, the intuitive heart of the distinction is between those reasons that are reasons for some agents but not for others and those reasons that are reasons no matter who you are. For example, I may have a reason to hold a birthday party for my child because it is my child. But many would doubt that you have a reason to hold a party for my child or even to help me hold one (though you might have a reason to hold a birthday party for your child). The reason depends on who I am. By contrast, if a stranger is about to step accidentally in front of an oncoming bus and I can pull him back, then I have a reason to do so. In this case, however, many people are inclined to agree that this is a reason anyone else has as well, or at least would have, provided only that they were in a position to do something about the matter.

The contrast between agent-relative and agent-neutral reasons is of importance in part because agent-relative reasons seem to be at play in the kinds of personal values discussed in the prior section. But many philosophers have also come to see them at work in important aspects of moral thinking, especially in the nature of deontological prohibitions on certain kinds of action. On one plausible interpretation, a person committed to a prohibition against, for example, killing the innocent, will care deeply about who does any killing. Though such a person may recognize any killing of the innocent to be bad, it may matter greatly to them that they not be the one doing the killing. Because many philosophers are interested in defending the rationality of such moral norms, locating their place in an account of the kinds of reasons that agents may have has become a critical question.

The Rise of Naturalism in Moral Philosophy

For much of the twentieth century, the empirical study of moral judgment, norms, and behavior was given little attention by moral philosophers. This state of affairs is undergoing a profound reversal. The present discussion will not attempt to summarize the state of developing research, but three types of inquiry are notable.

First, the rapid development of evolutionary biology spawned renewed interest in developing accounts of how moral norms might have arisen out of a process of evolution. Of course, the suspicion that moral norms do have some such history is an ancient one, but the techniques of modern evolutionary research, including the tools of game theory and the computer simulation, have made it possible to better develop and critically assess possible explanations. Of particular interest are norms regarding helping behavior (or altruism), cooperation, and fair dealing. There are often significant differences in the use of terminology between those conducting this empirical research and those engaged in more traditional moral philosophy. For example, in discussions of the evolution of moral norms, altruistic behavior is often any behavior that in fact benefits another whereas for many traditional moral philosophers, behavior is altruistic only if it is undertaken for the sake of benefiting another. So long as these terminological issues are treated with care, however, they do not seem to present any decisive obstacles.

Another area of rapidly developing research is the application of neuroscience and cognitive science to the topic of moral judgment. While moral philosophers have long deployed hypothetical cases as intuition pumps, the recent use of brain scanning techniques appears to reveal that moral thinking about different kinds of cases involves activity in distinct brain regions. Such results are of interest not least because many moral arguments depend upon claims that different cases are analogous and so merit comparable analysis. The science involved in these studies is both complex and rapidly evolving, and many philosophers and scientists expect increasingly fine-grained and thorough results.

A third area where empirical research has blossomed and impacted moral philosophy is in the area of social psychology. Moral theories of all stripes attribute to human beings beliefs in moral principles, or acceptance of moral norms, or possession of virtuous character traits. In each case the attribution typically brings along with it an expectation that an agent of whom it is true will be appropriately motivated to act accordingly. In this way, moral theories claim that agents have certain moral outlooks and that these outlooks impact the agents' behavior. In short, moral theories make claims about agency. Whether agents really are so motivated, however, appears to many to be an empirically testable hypothesis. Using the tools of social psychology, some scientists and philosophers have begun to emphasize the degree to which human beings of all stripes seem to be influenced by what would seem to be morally irrelevant factors.

For example, one might have thought that whether a person would help a stranger would depend largely on whether that person was a good person (perhaps because they have the virtue of kindness, or because they accept some moral principle that dictates helping others). Experimental studies, however, seem to reveal that whether people help each other is highly correlated with such factors as whether they are in a good mood, a factor that most would count as morally irrelevant and as precisely the kind of thing that sound moral commitment would get round. Thus, some have suggested that certain moral theories may rest upon dubious or false presuppositions about human agency.

In each of these cases, the precise relevance of empirical findings to more familiar questions of moral philosophy is disputed and uncertain. Few, if any, researchers believe that such empirical findings straightforwardly reveal which of our moral commitments are worthy of our endorsement and which are not. Brain scans do not tell us whether a moral intuition is to be trusted or not; evolutionary accounts of the development of norms do not tell us whether those norms are morally worthy or not. At least they do not do so in any simplistic way. Neither, however, do many philosophers assume that such empirical findings are ultimately irrelevant to the familiar normative questions of moral philosophy. For many moral philosophers, the question is not whether empirical science is relevant but how so. The absence of any consensus answer to this question may be due in part to the fact that the empirical sciences in question are not yet fully developed. Perhaps as we get a better scientific picture of the nature and history of moral norms and judgment, the relevance of this picture to normative questions will become clearer. Of note as well, though, is the fact that there is no agreed-upon epistemology for settling normative questions, and unless there is, it seems unlikely that philosophers will be able to agree about the relevance of empirical studies. Indeed, one may suspect that questions of how empirical results are relevant to normative questions will itself become an important locus of dispute (if it is not so already) in assessing rival moral epistemologies. It is often remarked that Moore's writings set the stage for the development of twentieth-century moral philosophy, and in many ways, they did. But he surely would not have written this ending.

See also Anscombe, Gertrude Elizabeth Margaret; Consequentialism; Empiricism; Enlightenment; Epistemology; Foot, Philippa; Hare, Richard M.; Hedonism; Hume, David; Idealism; Intuition; Kant, Immanuel; MacIntyre, Alasdair; Mackie, John Leslie; Mill, John Stuart; Monism and Pluralism; Moore, George Edward; Nagel, Thomas; Naturalism; Parfit, Derek; Plato; Rawls, John; Ross, William David; Sidgwick, Henry; Singer, Peter; Utilitarianism; Virtue Ethics; Williams, Bernard.


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Sean D. McKeever (2005)

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