Here's the first article I mentioned above. It's a good and short (2.25 pages) overview of the question "why by moral," and whether the existence of God helps. This author, philosophy professor Keith parsons, comes from an agnostic or atheistic point of view.
----------------

Why Be Moral? A Dilemma for Nontheists? (2001)
Keith M. Parsons

"Why be moral?" was basically the question Thrasymachus put to Socrates. According to Thrasymachus, the ideal life would be to have a reputation for perfect justice while being completely unjust. That way you could enjoy all the advantages of injustice while basking in the glow of a good reputation. Socrates had to show that it would be better to be perfectly just even at the price of being thought unjust. Of course, the Christian could say that the unjust man will face judgment in the hereafter, and that this is a reason to be just. However, this misses the point. The question "Why be moral?" is not asking for a prudential consideration. It poses the metaethical question "What is the source or ground of moral obligation?" In other words, why ought we to do anything?

There are two ways a Thrasymachus could defy us to show him that there are genuine moral obligations. One would be to defend moral skepticism, i.e., to argue that there may be truths about right and wrong, but that these cannot be known. The second would be to assert moral nihilism, the claim that there are no true ethical principles. I shall focus on this second option here.

Moral nihilism holds that ethical judgments do assert cognitive claims, so that emotivists and other noncognitivsts are wrong to think that ethical utterances merely express feelings or commitments. Yet, nihilism holds that all such claims are in fact false. One prominent nontheist, J.L. Mackie, did adopt a form of moral nihilism. According to Mackie's "error theory," we all tend to think that there are true ethical principles, but we are wrong.

Therefore, no answer can be given to Thrasymachus. Now from a "public relations" standpoint, it might be bad for nontheists to adopt such nihilism. But so what? Nontheism will never be as popular as theism. Besides, in the true spirit of Socrates, we should value truth rather than popularity.

Still, many nontheists would repudiate moral nihilism and defend some form of ethical objectivism, i.e., the view that some things just are--universally--right or wrong. Here it is important to distinguish ethical objectivism from moral realism. Moral realism holds that ethical principles are universally valid independently of human choices. One can be an ethical objectivist and still hold that ethical principles are in some sense constructed by human choices, or at least hypothetical choices. John Rawls is a case in point. He famously asks what sorts of moral rules we would have chosen if, prior to being born, we had been placed behind a "veil of ignorance" where we would have no knowledge of our future status. That is, we would not know whether we were destined to become a prince or a pauper, attractive or ugly, strong or weak, brilliant or slow, educated or illiterate, or anything else that would give us advantages or disadvantages vis-a-vis others. In such a situation, Rawls argues, we would all opt for justice and fair play, with certain inalienable rights and equal chances for all to compete for life's goodies. Why be just? Because that is what each of us would have chosen had we decided from behind the veil of ignorance.
But can moral realism be defended from a nontheist position? Clearly it can. One could be an intuitionist and hold that rightness or wrongness are objective, non-natural properties that supervene upon certain acts, policies, etc. Such intuitionism has been regarded as metaphysically extravagant by its critics, but it certainly seems no more extravagant than to invoke the God of the "omni" predicates as a basis for moral realism. For the intuitionist, a Thrasymachus suffers from a failure of his intuitive faculties; he is like a person born blind. Anyone with normally functioning intuitive abilities will just see, e.g., that the gratuitous infliction of harm is intrinsically wrong and therefore ought not to be done.

Of course, intuitionism is only one of many options. One could also take the Kantian line that the fundamental rule of morality, the categorical imperative, is simply a deliverance of reason. In this case, a Thrasymachus who demands to know why he should act only on that maxim that can consistently be willed to apply universally, would just be missing the point.

Now it is well known that none of the standard ethical theories is without problems. Still, it is hard to see that the nontheist, qua nontheist, is at any special disadvantage here. No ethical system has won anything like universal agreement, not even (perhaps one should say especially not) ones that invoke theism. For instance, natural law theories have few advocates outside the Catholic Church. The moral nihilist has the job of showing that all these theories are false or at least implausible. That is a heavy enough burden, but even that is not enough to support nihilism. The nihilist has the task of showing that judgments like "it is wrong to inflict gratuitous harm" are reasonably thought not true, not merely that no ethical theory has yet shown why they are true. With all due respect to the late, great J.L. Mackie, I do not think this has been done.

Now I may have gotten Thrasymachus wrong so far. It could be that he is not doing anything as profound as asking the metaethical question about the grounds of moral obligation. The answer to that question would be to give an acceptable metaethical theory, the sort of answer I outline above. It could be that Thrasymachus is just a dull immoralist who is saying "Even if x is the right thing to do, I don't care. Nyah Nyah!" There just is nothing philosophical to say to such immoralism because it is beyond reason. We might invoke prudential considerations as a motivation. Here theists definitely have an advantage since they can threaten hell (though people seldom think that hell is for them). All nontheists can do is point out, correctly I think, that bad people usually have rotten lives. Even if they die rich, they usually die unloved. They can buy sex from prostitutes or trophy wives, but not affection. They may be surrounded with sycophants, but will have no real friends. Their lives are filled with suspicion, anxiety, cynicism, disappointment, and loneliness.

Thrasymachus's tricks may work for a while, but, as Lincoln sagely observed, you cannot fool all the people all the time.

In summary, the question "Why be moral?" strikes me as a nonproblem, or at least no more of a problem for the nontheist than for the theist. Each can address the problem only by developing an acceptable metaethical theory, and it is not clear that this has yet been accomplished by anyone. It is even less clear that the theist will have an easier time developing one than the nontheist.

Here's the second article I mentioned above. It's from the Stanford Encyclopedia of Philosophy; the author comes from a philosophical position known as "Practical Moral Skepticism":

------------------------


Practical Moral Skepticism

Practical moral skepticism answers the common question, "Why be moral?" This question, like many philosophical questions, is too short to be clear. It can be expanded and explained in several different ways.

The first word that needs to be clarified is "Why". This interrogative asks for a reason, but reasons are understood in different ways. Some philosophers suggest that all reasons are self-interested. Then the question "Why be moral?" asks "Why is it in my interest to be moral?" Others, in contrast, argue that some reasons concern effects on others (rather than oneself) or do not concern any effects on anyone. Then the question "Why be moral?" is not just asking why it is in my interest to be moral. Instead, it asks what, if anything, makes it irrational to be immoral or at least keeps it from being irrational to be moral.

The next clarification concerns the phrase "be moral". The question "Why be moral?" might seem to ask, "Why should I be a moral person?" This should be distinguished from the question, "Why should I do moral acts?", if there can be isolated cases where I have no reason not to do a particular immoral act (such as hurting this friend or cheating on this exam) while I still have reason not to want a wider tendency to do immoral acts (such as hurting and cheating regularly). Only such wider tendencies or character traits make someone immoral as a person, but it seems harder to imagine how there could be no reason to avoid such widespread tendencies. If immoral tendencies always directly or indirectly hurt other people, and if some reasons are facts about interests of other people, then there will always be reason not to be an immoral person. Even if reasons are restricted to self-interest, widespread tendencies to immorality might always be dangerous to the agent's self-interest, and then, again, there will always be reason not to be an immoral person. Practical moral skeptics might try to describe cases where a widespread tendency to immorality is in one's self-interest, but critics will respond by calling such cases unrealistic. Whether or not a realistic example can be found, the focus on immoral people or character traits at least makes it easier to argue that real agents always have some reason to be moral people.

The other question, "Why should I do moral acts?", can still be interpreted in different ways, including "Why should I do acts that are morally good?" or "Why should I do acts that are morally required?" These questions are distinct if some acts, such as giving to a particular charity, are morally good but not morally required. If I have no reason to do such an act, then I do not always have a reason to do what is morally good, but I still might always have a reason to do what is morally required. For simplicity, the rest of this entry will focus on practical moral skepticism about what is morally required.

What such practical moral skeptics deny is that I always have reason to do what is morally required. In other words, they deny that I always have reason not to do what is morally wrong. These claims are equivalent because it is morally wrong not to do what is morally required. Practical moral skeptics do not deny that there is sometimes reason not do what is morally wrong. After all, some wrongdoers are caught and punished. However, practical moral skeptics can still deny that there is always reason to do what is morally required or to avoid what is morally wrong.

How much reason? Some practical moral skeptics claim that sometimes there is no reason at all to do what is morally required. If all reasons are self-interested, this means that sometimes doing what is morally required does not serve the agent's interest in any way. That extreme position would be refuted if doing what is morally wrong always creates even a slight risk of some negative repercussion. A more plausible and common version of practical moral skepticism denies, instead, that there is always an adequate (or non-overridden) reason to do what is morally required. To establish this position, practical moral skeptics need only one case where there is overriding reason not to do what is morally required.

It is not hard to imagine such a case if reasons are restricted to self-interest. Just consider an agent who would receive great satisfaction from killing another person whom he hates and whom he can kill without cost because he will die soon anyway. Killing then serves that agent's self-interest, even if it is still morally wrong. Other cases would work as well. If overall self-interest ever conflicts with moral requirements, then there will be overriding reason not to do what is morally required, on the assumption that all reasons are self-interested.

Without that assumption, such practical moral skepticism becomes much less plausible. If harms to others give agents reasons for and against actions, then this agent has some reason not to kill the victim. If that reason overrides the agent's reason to kill, then the agent will not have an adequate reason to kill. Of course, the agent's reason not to kill might also not be overriding. The reasons might be equal or incomparable in some way, in which case each is adequate, but neither is overriding.

This position is closely related to the claim that, when self-interest conflicts with moral requirements, neither alternative is irrational. If so, it is not always irrational to do what is morally wrong, but it still might never be irrational to do what is morally required. (Cf. Sidgwick 1966.) It does not matter much whether this position is classified as a version of practical moral skepticism. It is skeptical insofar as it denies that immoral actions are always irrational. It is anti-skeptical insofar as it claims that moral actions are never irrational.

Copyright © 2002
Walter Sinnott-Armstrong wsa@dartmouth.edu
For the original link, plato.stanford.edu/entries/...ment.html

This is the third reading mentioned above, and it's from an essay in the Stanford Encyclopedia of Philosophy called "Game theory and Ethics" by philosophy professors Bruno Verbeek and Christopher Morris, plato.stanford.edu/entries/game-ethics/

This is section 5, "Morals By Agreement," the part relevant to "Why be moral":

----------------------


5. Morals by agreement

One of the most influential contractarian theories currently around is that of David Gauthier. His theory, however, is different from other contractarian approaches, not only in its extensive use of game- and bargaining theory, but also in the following respect. One of the difficulties we signaled with regards to the functionalist approach is that it provides no answer to the question “Why be moral?” It is here that Gauthier's contractarian theory distinguishes itself from those of Rawls, Harsanyi, and others. Gauthier not only uses bargaining theory to determine, as Rawls and Harsanyi sought to do, the content of fundamental moral principles; he also tries to show that rational agents will act morally. For this reason we discuss it in more detail than the others.

Gauthier's moral theory, “morals by agreement” (Gauthier 1986), is a theory about the nature and rationality of morality. (See also Section 3 of the entry on contractarianism). It consists of four parts. The first is an account of practical reason and the natural condition of humankind, much of it familiar to rational choice theorists and to contractarian moral theorists (Gauthier 1986, chapters 2-4). Next is an account of the principles of conduct that rational agents would hypothetically agree to — a kind of “social contract” (Gauthier 1986, chapter 5). The third element is a controversial revisionist account of practical rationality essential to his argument aiming to show that virtually everyone under normal circumstances has reason to accept and to abide by the constraints imposed by these principles (Gauthier 1986, chapter 6). Lastly, Gauthier argues that the principles in question are principles of morality, an argument which makes implicit reference to a functionalist account of moral norms (Gauthier 1986, chapters 7-8). The third part is Gauthier's answer to the question “Why be moral?”. It touches upon some very fundamental issues in game- and decision theory, which is why we discuss it a bit further here.

As Hobbes already realized, it is one thing to come to an agreement; it is quite another thing to perform one's part of an agreement. Morality, at least as it is traditionally conceived, often requires us to sacrifice our interests or aims. This is, at least on the face of it, contrary to what rationality requires. Gauthier's response to this is to argue that we misconceive practical rationality, even instrumental rationality, if we think the aim of rationality determines in any straightforward way the manner in which we should reason or deliberate. The aim of rationality — to do as well as possible — does not necessarily determine our principle of decision — for instance, to choose the best alternative at each moment of choice. In terms of the utility-maximizing conception of rationality which he has accepted until recently (Gauthier, forthcoming), Gauthier argues that the aim of maximizing utility does not mean that we should, at each decision point, maximize utility. Instead we should reason in ways which are utility maximizing. Just as it is sometimes the case that we do best or at least well by not aiming to do best or well, so it may sometimes be that the utility maximizing course of action is not to maximize utility at each decision point. Given that our mode of reasoning or deliberation itself affects our prospects, our aims or purposes are sometimes best served by our not seeking to do best at every decision point.

Gauthier's discussion in Morals by Agreement is conducted in terms of “dispositions to choose” and specifically of “constrained maximization”, the disposition to cooperate with other cooperators even in circumstances where defecting is more advantageous. In later work Gauthier develops his revisionist account of practical rationality in terms of rational plans and intentions and of modes of deliberation. If we grant that agents may do better in any number of circumstances by acting in ways that are not “straightforwardly maximizing”, the problem is to determine how acting as a constrained maximizer is rational. In the book Gauthier assumes that if our dispositions to choose is rational, then our choices determined by these dispositions are also rational. A number of theorists have followed Thomas Schelling in arguing that it is often rational to do things that are irrational, but they argue that the latter do not in the circumstances cease being irrational. Gauthier thinks that if a course of action is better than any other in its effects, then it may under certain conditions be rational to adopt it and to intend to carry out its element even if some of them are not, from the standpoint of the moment of execution, the best thing to do in terms of one's aims or purposes. He seeks therefore to establish that if a mode of deliberation or a plan of action is rational, then acting according to it can be rational even if so acting requires doing things that are not, considered from the standpoint of the moment of action, optimal. Principled action constrains one's action, and it is rational to be so constrained. Thus, if Gauthier is right, it can be rational to abide by certain norms or principles, even when they require acting in ways that are not best from the standpoint of the time of action. Much of Gauthier's work since Morals by Agreement develops and defends this revisionist account of practical rationality. (See Gauthier 1994, 1996, 1998a and b. For an alternative revisionist account, see McClennen 1990).

Gauthier's defense of “constrained maximization” constitutes a major revision of standard game- and decision theory. Orthodox theory focuses upon the rationality of actions at the time of choice. The mode of deliberation itself about actions falls out of the scope of the theory. (Or rather, orthodox theory presents itself as such a mode of deliberation.) Some critics have argued against including the mode of deliberation in the scope of the theory (for example, Velleman 1997). Most game theorists, however, argue instead that if it is feasible to choose the mode of deliberation, this choice itself can be modeled as a move in a more complex decision game, thus including Gauthier's proposal into standard theory (for example, Binmore 1994, p. 179-182).

I found a few more references

philosophy.lander.edu/ethics/...ral.html

pixnaps.blogspot.com/2005/06...ral.html

www.acton.org/publicat/m_...n1-clark.pdf

www2.sunysuffolk.edu/pecorip...rior.htm

www.iep.utm.edu/e/ethics.htm

Thanks to those of you who sent me links to more good articles on "Why Be Moral" that come from a different point of view and offer different arguments from the one's I listed above. So, at the risk of overwhelming you with too many little things to read or skim, check out the links below. As always, feel free to read or skim any one or more of them, or none of them. Most importantly, come to our discussion with your own ideas and questions! However, these readings will give you food for thought, and probably will improve your thinking on this classic philosophical conundrum.

First, this interesting magazine article, coming from a strongly theistic point of view, attempts to give answers to why one should be moral, and argues that God is necessary for an objective morality. Thanks to Tim for this link, www.chabad.org/magazine/article.asp

I thank Ron for these three, good readings. The first is an excellent mini-essay (4 pages long) posted to a philosophy blog, followed by several brief responses by readers, pixnaps.blogspot.com/2005/06...ral.html

The second reading, made for a college class, is a short (2.5 pages) outline of several traditional ways of approaching the "why be moral" question, but it doesn't try to provide answers, philosophy.lander.edu/ethics/...ral.html

The third one, an excerpt (5.5 pages long) from a book on the philosophy of religion, examines secular versus religious approaches to providing an objective basis for morality and "why be moral," www2.sunysuffolk.edu/pecorip...rior.htm