This quote is a critique of moral relativism and subjectivism. One approach to ethical philosophy is that morals are different for other cultures and individuals, and that there is no such thing as absolute good or bad exterior to the human mind and emotions. This quote disagrees, saying that their are exterior Moral absolutes.
Socrates was not a moral relativist, his were what is called Virtue Based normative ethics. He believed the virtue of WISDOM, knowledge of the good, was what made people do good. Anytime anybody does something bad it is because they are IGNORANT of the good thing to do. He reduced all evil to lack of education or misunderstanding the situation. Socrates believed that there was an absolute Good to know and not that each person had their own concept of good.
