In Political Liberalism (1993), Rawls turned towards the question of political legitimacy in the context of intractable philosophical, religious, and moral disagreement amongst citizens regarding the human good.

There is nothing new about moral disagreement.

Eberhard is passionate about sportscars but has moral disagreements regarding dependence on oil imported from the Middle East and is also concerned about global warming.

Expressivists argue that such deep moral disagreement is evidence that moral judgment is not a species of descriptive or factual judgment.

Why does the moral sense not settle moral disagreements in a similarly simple way?

For Stevenson, moral disagreements may arise from different fundamental attitudes, different moral beliefs about specific cases, or both.

And aesthetic judgement can be upset just as disastrously--more disastrously, because the cause is less readily recognized--by political or moral disagreement.

There is a fundamental moral disagreement that laws and Supreme Court justices will never change.

Where a subjectivist sees no moral disagreement (because he believes "X is right" just means "I approve of X"), the projectivist can allow for moral disagreement.

Some of the main topics of the field are moral responsibility, moral development, moral character (especially as related to virtue ethics), altruism, psychological egoism, moral luck, and moral disagreement.