Are there some deliberate actions that are always immoral, no matter what the circumstances are?

Take abortion, for example. Or euthanasia. Is it always wrong to deliberately end an innocent human life?

Traditional Christian moral philosophy gives a clear answer: yes.

Many classic Christian works of philosophical argumentation explain why that affirmative answer is true.

The philosopher Dietrich von Hildebrand wrote one such study. The book was first published in 1955 as True Morality and Its Counterfeits. A German edition followed in 1957, and then another English edition (with a new epilogue) in 1966 with the new title Morality and Situation Ethics.

This month the Hildebrand Project republished the book, and one of our finest contemporary Catholic minds, John Finnis of Oxford University, has written an introduction to the new Hildebrand Press edition.

It is worth owning, not just for Hildebrand’s classic argumentation, but also for the new introduction added to it by Finnis.

Finnis is no stranger to the question of moral absolutes. His monumental study Natural Law and Natural Rights, along with two shorter books on ethics (Fundamentals of Ethics and Moral Absolutes), explains the eminently rational basis for traditional moral doctrine.

Finnis is also an exemplary contributor to the field of moral philosophy. In his book Aquinas: Moral, Political, and Legal Theory, he cogently sets forth what St. Thomas Aquinas has achieved in that field, and yet he also persuasively explains what Aquinas left unfinished.

Serious work in moral philosophy still remains to be done. Because Finnis has been one of the foremost contributors within the Catholic intellectual tradition to that ongoing need, he is perfectly suited to write a retrospective introduction to Hildebrand’s book.

In it, Finnis explains the historical context for the years 1955–1966, in which Hildebrand was making his philosophical defence of traditional Christian morality.

After the Second World War, various currents in philosophical thought called into question the traditional idea of moral norms that admit no exceptions.

It seems hard to fathom such a trend after the horrors of that war. But perhaps the unprecedented experience made it easier to entertain the idea: as if there were an exception to everything; as if the unexpected must be freshly accommodated.

Yet the project of calling into question “exceptionless moral norms” – and thereby removing moral absolutes from moral philosophy – was an obvious threat to traditional Christian approaches to morality.

Simply as a matter of practice, Christians had been perennially famous for their countercultural witness to exceptionless moral norms. For example, the Letter to Diognetus, from the second century after Christ, testifies to the Christian refusal to practise infanticide, which at that time was done by abandoning babies outside and leaving them exposed to the elements.

The Letter to Diognetus says this of Christian morality: “Like others, they marry and have children, but they do not expose them. They share their meals, but not their wives. They live in the flesh, but they are not governed by the desires of the flesh. They pass their days upon earth, but they are citizens of heaven. Obedient to the laws, they yet live on a level that transcends the law. Christians love all men, but all men persecute them.”

Because of this traditional Christian witness to exceptionless moral norms, many famous Christian voices arose after the Second World War to defend the idea of moral absolutes.

The systematic theologian Karl Rahner wrote two important essays in 1949 and 1950, later published as part of his 1963 book Nature and Grace.

In April 1952, Pope Pius XII gave an important speech on the subject of moral absolutes. Hildebrand brought the argument of that speech into his book.

For Hildebrand and the Christian tradition, there is such a thing as “true morality,” despite fashionable attempts to substitute a “counterfeit” morality. In his own time, Hildebrand’s book sought to defend traditional moral philosophy from the idea of “situation ethics.”

In situation ethics, morality takes its bearings from the situation at hand, but in a way that fails to admit the proper role of “exceptionless negative norms” in deliberation and choice.

Finnis judges that Hildebrand’s work in ethics presents “a fine album of snapshots of the sound Christian conscience”; but, in philosophical terms, Hildebrand’s work circularly tends to “presuppose its own correctness” at many points, rather than provide a rigorously complete defence of Christian morality on the basis of “philosophically first principles.”

On the basis of first principles, Finnis sagaciously provides readers of the new edition with a sound overview of the controversies in moral philosophy and Church teaching since Hildebrand’s notable effort to defend true morality.

Finnis thus proves an indispensable guide for anyone interested in carrying forward the noble philosophical work of Christian thinkers as diverse and as serious as Aquinas and Hildebrand.