In his 1738 book “A Treatise on Human Nature,” Scottish philosopher David Hume noted that in his exploration of different systems of morality, he had found author after author shifted from discussions of facts (what is) to discussions of values (what ought to be) without admitting and explaining the logical connection between the two: In every system of morality, which I have hitherto met with, I have always remarked, that the author proceeds for some time in the ordinary way of reasoning, and establishes the being of a God, or makes observations concerning human affairs; when of a sudden I am surprised to find, that instead of the usual copulations of propositions, is, and is not, I meet with no proposition that is not connected with…