Finnis critiques a number of authors and philosophical traditions, thereby offering polemical support for his conception of Natural Law.

Whilst following them, he also notes substantive limitations in Aquinas’ and Aristotle's accounts of Natural Law.

Such choices are guided through participation in (through a natural apprehension of), and (subsequent) reflection on, the basic goods (listed in the next section).

Thereby, they lose their moral authority since individuals will be inclined to disregard them as not satisfying their own understanding of a good life.

Incidentally, Finnis argues that people should not despair from failing in their life goals, provided they have participated in the basic goods.

The postscript systematically reviews all the arguments in the book, expanding and clarifying them by reference to Finnis' other writings.