[M]oral systems are an informal analogue of public law, with the difference that each person has the responsibility of deciding for himself what set of laws he will follow in his conduct and advocate for others.
(Richard B. Brandt, Ethical Theory: The Problems of Normative and Critical Ethics, Prentice-Hall Philosophy Series, ed. Arthur E. Murphy [Englewood Cliffs, NJ: Prentice-Hall, 1959], 263)
