Is morality a concrete sociological factor that has social consequences? Or is it simply a theoretical construction by philosophers and other moral theorists and advocates?
Human beings act, and their actions are often influenced or even determined by their moral values. This seems to be an empirical fact. (They also act out of self-interest, out of cruelty, out of disregard for others, out of impulse, and in a variety of other ways in which ethics plays no part.) An adequate theory of human deliberation and agency appears to require an account of how values and moral commitments figure into ordinary decision-making and agency. This fact, in turn, seems to provide the beginnings of a basis for a "yes" to the question of whether morality is socially real. Ethical values and norms are a behavioral reality; and this fact about individuals also has aggregative consequences for group behavior (in politics and in ordinary life).
But now shift the focus a bit and consider "philosophical ethics" -- the writing and thinking about ethical principles by philosophers (Mill, Sidgwick, Kant, Aristotle, Rawls, for example). Philosophical ethics is mostly about debates concerning ethical theories. Is the principle of utility the foundation of moral truth? Is the categorical imperative rather the foundation? Are there rational grounds for choosing Kant's moral system over Bentham's? What does the principle of utility require -- maximizing average utility or total utility? Should utility consequences of an action be assessed through the consequence of this particular action or general rules of action that might govern this particular act? Do philosophy and logic have a basis in rationality to allow confident judgment about fundamental questions of ethics? These are abstract, theoretical debates. And it is hard to see how they could have direct behavioral effects. So we might say, "philosophical ethics is not a social factor."
So far, then, we have "morality in social behavior" and "ethics in philosophy". Is there a connection between the two realms? One possible connection is this: Our theory of human decision-making might incorporate a rational faculty of deliberation; so when people act "morally", a part of their deliberation is a consideration of reasons for and against a certain conduct. This is an empirical question. If we pursue this avenue, then ordinary actors are also moral philosophers; they are probing for reasons and facts that would tip the scales of judgment.
On the other hand, our theory of moral psychology might go in the direction of habit and inculcation rather than rational deliberation. We might hypothesize that individuals absorb a set of values and prohibitions, analogous to food preferences and aversions, and that these values are beyond rational deliberation and judgment. (Can one reason herself out of an aversion to eating dog?) On this approach, there is no connection between rationality and moral behavior, and philosophy and real social behavior do not intersect.
From a sociological point of view, it seems we need theories at several levels. We need a theory of the ways that individuals think, reason, and deliberate when they act (an empirical theory of practical agency). We need a theory of the social mechanisms and institutions through which individuals come to have the parameters and content of their deliberative systems set in particular ways. We need empirical descriptions of the real content of human moral deliberation in various groups and cultures.
Of particular importance for a sociology of morality is the question of the social mechanisms through which moral values and commitments are transmitted -- analogous to the question of how languages and practical skills are transmitted. How are value systems and styles of moral reasoning transmitted from one generation of individuals to another? That is, we need a theory of the "micro-foundations" of moral psychology and social development. And we ought to have an account of how it is that the psychological capacity for moral thinking has emerged through human evolution; are there "moral emotions" that support the efficacy of moral thinking in action? (Allan Gibbard provides some very interesting discussion on these issues in Wise Choices, Apt Feelings: A Theory of Normative Judgment.)
The perspective I favor is one in which we understand the individual as a deliberative reasoner, subject to non-rational as well as rational factors. The individual has a spectrum of choice; he or she can consider the nature of the action being contemplated, its fit with other values he adheres to, and the consequences of the action for others. Actions are not causally determined by an antecedent set of likings and aversions. So the individual has the capacity for functioning as his own philosophical consultant. On this perspective, the philosophical concepts of "deliberation" and "reflective equilibrium" are useful and illuminating about real human reasoners. So philosophy can contribute to our understanding of social cognition and decision-making.
At the same time, it strikes me that professional philosophers can contribute best to ethical deliberation and moral development when they refrain from foundational assertions and simply provide good illustrations of how deliberation and consideration of circumstances and consequences can most thoughtfully proceed. Philosophers should consider themselves as "deliberative consultants" rather than "deductive inference engines" when it comes to ethical reasoning.
This perspective allows for morality to play a role in social causation that is analogous to the role of rationality in economics and political science. Descriptive moral sociology can function in a way that is logically similar to rational choice theory, in that it represents a hypothesis about the nature of agency: when agents deliberate in such-and-so a way, within the framework of such-and-so moral commitments and such-and-so interests and goals, they are likely to behave in such-and-so a way.
(Thomas Nagel's The Possibility of Altruism is a particularly interesting and provocative work bringing together ethical theory and theories of real practical reasoning.)