Moral realism is the meta-ethical position that there are moral truths independent of subjective opinion.
Moral realism is a cognitivist approach to morality, in that it states that ethical sentences express propositions. Unlike error theory, however, moral realism holds that some of these propositions can be true.
The advantage of moral realism is that, if ethical sentences are propositions, then they can be evaluated and used to draw conclusions by means of logic in the way that other propositions can. This can lead to certain and unambiguous conclusions about ethical decisions. However, the obvious disadvantage of moral realism, which is shared with other forms of moral objectivism, is that the reality of moral truths cannot be proven, observed or accessed directly.