Loyalty is faithfulness or a devotion to a person or cause. The concept of loyalty is an important part of ethics. Plato originally said that only a man who is just can be loyal, and that loyalty is a condition of genuine philosophy. The philosopher Josiah Royce said it was the supreme moral good, and that one's devotion to an object mattered more than the merits of the object itself. Loyalty is a quality you look for in a friend.