I know that it provides such rules as I read it in an article but there was no reference to this statement.
(principle of non-contradiction: "the same thing cannot be affirmed and denied at the same time")
- The good
(principle of practical reason: "good is that which all things seek after.")
- as "whatever is a means of preserving human life, and of warding off its obstacles"
- "according to that nature which he has in common with other animals", "such as sexual intercourse, education of offspring and so forth."
- "according to the nature of his reason", "to know the truth about God, and to live in society"; "for instance, to shun ignorance, to avoid offending those among whom one has to live, and other such things"
On Friss-Grisez's "conventional natural law theory" view, see:
- Hittinger, A Critique of the New Natural Law Theory, ch. 2 "Natural Law, Moral Principles, and Ends", pp. 49-92
🎩 tip Prof Leon's comment