Since this is an introduction to ethics, we should begin by defining what ethics is. We could begin by saying that ethics is a branch of philosophy which seeks to establish and rationally defend a universally valid theory of what is right and wrong, good and bad in general, which can be used as a set of moral principles guiding human action. This is a reasonably accurate definition of ethics, but it doesn't give us a very clear or comprehensive sense of what ethics is all about. Perhaps the best way to do that is to see how ethics, or moral philosophy, as it is sometimes called, differs from a host of other activities associated with morality with which we are all familiar in everyday life. Some people believe that extramarital sex is wrong, for example; they criticize others for engaging in such activities, and they try to act in accordance with their moral beliefs, though they may not always succeed. Finally, they try to persuade other people to follow their example. Here, then, are several activities associated with morality in everyday life -- holding moral beliefs about what is morally right or wrong to do, passing moral judgments on other people and their behavior, acting morally or immorally according to one's moral beliefs, and offering moral advice and issuing moral commands to others. But, even though these activities are an important part of everyday morality, they do not constitute ethics itself. Unlike everyday morality, ethics is not primarily in the business of giving moral advice or laying down specific moral injunctions -- be honest, pay your debts, work hard, and so on. These tasks, important as they are, fall to parents, teachers, priests, rabbis, ministers and community leaders, who seek to encourage the adoption of and conformity to customary, socially-approved morality, and to offer guidance in cases where ordinary morality is not clear. But these activities must be distinguished from ethics, as we are using the term here to designate a branch of philosophy, namely, moral philosophy.

There is another, everyday moral activity, however, which brings us much closer to ethics. Let's suppose that Jack is one of those who believe that extramarital sex is morally wrong. But when he criticizes those who disagree with him and tries to persuade them to alter their moral beliefs and practices, Jack may well be challenged: "You say extramarital sex is wrong; I say there is nothing wrong with it. What makes your opinion any better than mine?" Of course, Jack may refuse to offer any reason to show why his moral position is superior to his friend's, but if he does try to justify his moral beliefs, then he is well on his way to engaging in moral philosophy, or ethics.

Ethics, in other words, is a theoretical discipline within the broader study of philosophy that attempts to discover why any action is right or wrong; that is, what makes an action right or wrong. Although there is nothing wrong with this account as it stands, we must say something more to avoid confusing ethics with certain aspects of ordinary morality. After all, we all give reasons in everyday life why our actions are right or wrong -- "The reason you shouldn't sleep with him is that he is married." In this case, we are simply reiterating the traditional moral principle that extramarital sex is wrong. Extramarital sex is always wrong, we are saying, in every and all situations, therefore it is wrong in this situation. But if ethics tries to discover why actions are right or wrong and this is what we do anyway in everyday life, does this mean that everyone is a moral philosopher and that we have been doing moral philosophy all along but not realizing that that is what we were doing? Not quite, although we are now getting very close. Moral philosophy (ethics) differs from ordinary reason-giving in everyday life in the extent to which such justifying reasons are pursued and in the level of their generality.

Suppose, to return to our righteous friend Jack, we ask him why it is wrong to sleep with Martin, and he replies that it is wrong because Martin is married and extramarital sex is wrong. If we agree with Jack, then this will probably settle the matter. "Yes, you're right; I hadn't thought of that (or, I didn't know that)." But if we are not convinced, we will want to ask Jack why he thinks extramarital sex is wrong. Again, Jack may be unwilling or unable to supply a good reason, but suppose he does offer a reason. "Extramarital sex is wrong," he may say, "because it causes marriage vows to be broken." Or, "It is wrong," he may say, "because someone may get hurt." But notice, these are not the ordinary reasons we find in everyday life for justifying particular actions; they are reasons used to justify other reasons. First, there is the particular action contemplated -- sleeping with Martin. Then there is the reason that has been offered why that is wrong, namely, that it is an example of extramarital sex that is wrong in principle. But there is also another reason, a kind of super-reason, which seeks to justify that reason, namely, that extramarital sex is wrong because it breaks the marriage vows (or, alternatively, because it will result in someone's getting hurt)...