Brandt 1959, p. 153: "[Objectivism and subjectivism] have been used more vaguely, confusedly, and in more different senses than the others we are considering. We suggest as a convenient usage, however, that a theory be called subjectivist if and only if, according to it, any ethical assertion implies that somebody does, or somebody of a certain sort under certain conditions would, take some specified attitude toward something."Brandt, Richard (1959). "Ethical Naturalism". Ethical Theory (英語). Englewood Cliffs: Prentice Hall. LCCN59010075。
