Moral realism is the belief that morality should be based on actual human behaviour and instincts, especially on self-interest. A form of moral realism is implied in most religions' claim that people cannot behave well without expecting heavenly rewards. A more sophisticated form of moral realism was presented by Aristotle who described a society based on self-interested citizens acting for common good. Realists want politics to be determined by actual balance of economic and military power, and actual tendencies within society. This way of thinking remained a strong influence within Western thought, though it was tempered by Christian ideal of love. In Chinese philosophy legalism is close to moral realism, as it promoted ruling through "tactics".
During the Enlightenment the idea of social contract arose on the basis of moral realism, and typically modernist ideologies such as liberalism, Marxism and nationalism are all based on self-interest, whether personal or collective. Charles Fourier used a peculiar variety of moral realism to justify his utopian phalansteres, organized in such a way that every person could have a job suiting their "passions". The neoreactionary movement promotes a more cynical variety of moral realism, an autocracy based on evolutionary psychology.
In foreign policy, realism was the dominant philosophy during the era of Concert of Europe and is still more widespread in European and especially Russian politics.
Moral realism is usually contrasted with moral idealism.