The moral argument is that it sets out to prove the existence of God from the evidence that morality exists in the world. The Platonic philosopher and novelist Iris Murdoch saw ample reason to believe in the idea of the Good without committing oneself to the belief in a God. Many moral theories argue that morality is a product of cultural and moral relativism: each society teaches it's young what is right and wrong, which results in our feelings of guilt when we do wrong. However, moral psychology is a product of God which seems less plausible than arguing that it is a biological product of social evolution. Another account, usually referred to as emotivism, argues that moral properties are a reflection of our feelings of approval or revulsion. For example, the moral doctrine 'killing is wrong' is not based on any kind of objective, universal moral law, but on the common human feeling of revulsion, and pity.