[E]very positive law, or every law strictly so called, is a direct or circuitous command of a monarch or sovereign number to a person or persons in a state of subjection to its author. And being a command (and therefore flowing from a determinate source), every positive law is a law proper, or a law properly so called.

Besides the human laws which I style positive law, there are human laws which I style positive morality, rules of positive morality, or positive moral rules. (134)

In consequence of the frequent coincidence of positive law and morality, and of positive law and the law of God, the true nature and fountain of positive law is often absurdly mistaken by writers upon jurisprudence. (162)

[Justice] Brandeis the other day drove a harpoon into my midriff with reference to my summer occupations. He said you talk about improving your mind, you only exercise it on the subjects with which you are familiar. Why don't you try something new, study some domain of fact? Take up the textile industries in Massachusetts and after reading the reports sufficiently you can go to Lawrence [Mass.] and get a human notion of how it really is. I hate facts. […]