This course traces the origins and consequences of the theory of natural law. Natural law is the idea that there is an objective moral order, grounded in essential humanity, that holds universal and permanent implications for the ways we should conduct ourselves as free and responsible human beings.

In Natural Law and Human Nature, you consider the arguments for natural law, the serious objections that have been raised against it, and the ways, despite all overt criticisms, it remains a vital and even pervasive force in political, moral, and social life today, even while traveling under another name.

Morality, Humanity, and BeingFather Joseph Koterski argues that views about ethics typically derive from views about human nature, and behind these, views about being itself. Thus no consideration of moral theories and their applications can be complete without an investigation of philosophical anthropology and even some consideration of metaphysical questions. These background issues will be things to keep in mind as you listen to or view the lectures.

You then turn your attention to the key arguments about justice that took place in the ancient Greek world, beginning with the pre-Socratic philosophers and the Sophists.

Classical Origins Shaping Father Koterski’s historical treatment is an appreciation of just how much thought, effort, and brilliance went into formulating and defending the crucial insights of natural law theory.

Father Koterski gives a clear example of this when he reconstructs the virtual dialogue that took place between the Ionian scientists, the Sophists, and their great interlocutors, Socrates, Plato, and Aristotle. Dealing not only with arguments about justice but also with questions about how change can occur (metaphysics again!), Aristotle (384–322 B.C.E.) pushed this debate forward dramatically by framing an account of nature and causation that laid the groundwork not only for natural law theory but also for modern physical science (which edits but does not erase Aristotle’s fourfold taxonomy of causes).

Father Koterski explains how Aristotle’s notion of nature as an inner, goal-oriented dynamism set the stage for progress in moral understanding by allowing thinkers to distinguish more readily—albeit never perfectly—between the natural on the one hand and the merely habitual, customary, or familiar, on the other.

Aquinas: The First Systematizer Yet Aristotle, although a major figure in the tradition, cannot be called a natural law thinker. The rise of natural law thought was the fruit of later developments, including the rise of Stoic philosophy with its emphasis on universal human dignity and divine providence, the powerful contributions made by biblical religion, and the tradition of Roman jurisprudence, particularly as expressed by Cicero.

The first thorough treatise on natural law came as part of the Summa Theologica by Thomas Aquinas (1224–1272). Working with newly recovered Aristotelian works as well as the Stoic, biblical-patristic, and Roman traditions, Aquinas set out the account of natural law as that type of law through which humans take part according to their nature as free, intelligent, and responsible beings. He remains to this day the philosopher whose name is most closely associated with natural law.

The Modern Turn Next you review the major developments that natural law thinking has undergone since the inception of the modern period about half a millennium ago. The big questions here are how and why natural law theory, which for Cicero and Aquinas had seemed a “conservative” force, became a doctrine of sociopolitical transformation and even revolution in the hands of Hobbes, Locke, and others.

At this point, the narrative “comes home” to America as Father Koterski explores the ways, by the American Founders’ design, natural law thinking is poured into the foundations of our republican experiment in ordered liberty and constitutional democracy.

You look too at the criticisms leveled against natural law by Descartes, Rousseau, and Kant, pondering all the while Father Koterski’s suggestion that they owed natural law theory more of a debt than they were willing to admit or than might be apparent at first glance.

Challenges and Objections In the course’s final third, you leave the narrative historical framework and turn to a series of topical discussions. Natural law theory today has many critics and faces numerous questions. No philosophical treatment of the subject would be complete without a fair and careful consideration of these.

Father Koterski asks whether modern evolutionary biology can claim to have discovered truths about human nature that render natural law theory unintelligible, whether the findings of anthropological research undercut natural law, and whether accepting the idea of natural law means accepting the existence of God and vice versa.

Controversies and Contemporary Applications The final lectures move from principles to particulars by explaining how natural law reasoning might apply to a range of hotly debated contemporary issues. In the legal arena, you will consider the debates over human rights and the use of the courts in promoting social reform during periods when consensus has not yet developed.

In the sphere of medicine and bioethics, Father Koterski explores natural law arguments regarding the controversial questions of abortion, euthanasia, and stem cell research. In the sphere of social ethics, he asks how natural law would counsel us to think about the family as well as about structures of human obligation more generally.

Finally, he compares natural law theory to the relativist and positivist views that are commonly encountered today, particularly in the academy, and argues that natural law, to its credit, retains an emphasis on human reason that is not to be found in the many forms of contemporary thought that treat humans primarily as willing, rather than thinking, beings.