Margaret Simon, my sixth grade English teacher and grammar martinet, would have been shocked by this book’s title: What We Can’t Not Know: A Guide . Back in 1970 I learned, under pain of death, never to use a double negative. But that was thirty-some years ago. Today, Miss Simon might be shocked by an even greater claim: that such basic moral principles as the Decalogue itself are believed, by many of the West’s most vocal elites, to be unknowable.

The unknowability of the Commandments lies in the epistemological terra incognita of modern and postmodern thought, which denies a human capacity to know anything with certainty in ethics or morality. What is called moral knowledge may be a reflection of the interests of the dominant class, race, gender, etc. It may express subjective feelings or sentiments. There’s but one thing moral knowledge is not, at least according to reigning opinion: it is not real knowledge, knowable with certainty, which imposes a claim precisely because it is knowable.

In some ways, then, J. Budziszewski’s book could not be more untimely. Its thesis”that there are certain basic moral truths that human beings just plain can’t not know”would have hardly generated a yawn for most of the past three thousand years of Western history. Yet today, that same thesis is liable to provoke a firestorm as intense as when Supreme Court Justice Clarence Thomas started paying compliments to such extremist and radical notions as Aristotelian natural law theory.

The erosion of confidence in the certainty of moral knowledge has been developing for some four centuries, although it has come to widespread notice only in the past three generations. Budziszewski labors under no illusions: he doesn’t for a moment believe he can reverse the philosophical tide with one book. One might even say he’s writing to the choir, for he acknowledges his audience to be “the persuaded, the half-persuaded and the wish-I-were-persuaded”; he aims to reassure “plain people [of] the rational foundations of the common moral sense.” That’s not an unimportant task when, living in the topsy-turvy world of postmodern moral laxity, those who are convinced of the possibility of morally certain knowledge often feel like the last sane men in the madhouse.

Budziszewski argues that “a good deal” of the moral knowledge we can know with certainty is encapsulated on both tablets of the Ten Commandments. Budziszewski stresses the relevance of God to the ethical enterprise, devoting an entire chapter to detailing the deficiencies of what he calls “the Second Tablet Project.” Since it is at a minimum passé to speak of God publicly, there are those who try to make the Decalogue more palatable to modern sensibilities by lopping off those Commandments directly referring to God, concentrating instead on the ones that govern human relations more generally.

Against this approach Budziszewski insists that man’s natural knowledge of God is essential to his natural knowledge of morality: a naked public ethic is as dangerous as a naked public square. Such a “godless natural law” entails nothing less than “a direct attack on humanity itself,” because it “would revere the laws of human nature only insofar as we continued to be human. Denying that our humanity is a creation, it would have no reason to preserve this humanity, and no objection to its abolition.” Jettisoning the idea of creation also destroys both the notions of obligation (reducing it to a cautious prudence that restrains no one but the timid) and order (replacing it with arbitrariness and caprice by denying any basis for a unifying principle of reality).

Budziszewski adduces four “witnesses” to testify to the human capacity for certain moral knowledge: “deep conscience” ( synderesis ), design as such, our own design as human beings, and natural consequences. He also examines how the human being who denies these moral truths steeps himself ever deeper in perverted forms of remorse, confession, atonement, reconciliation, and justification, all in the vain attempt to convince himself and others that evil is really good. These five practices, if engaged in sincerely, can reorient the person back to the objective true good. But sincere remorse, confession, atonement, reconciliation, and justification demand that the wrong one has done be acknowledged and repented. The most basic truth of our capacity for certain moral knowledge is, after all, the first principle of practical reason: do good and avoid evil. Nobody asks, “Why do good?” The good is self-justifying, so much so that even its counterfeits want to trade in its value.

The human orientation toward good is so fundamental that even when moral agents do evil, they inevitably seek to redefine it as good. Budziszewski insists that such efforts are self-deceptions, because human beings cannot evade the deepest voice of conscience pronouncing their deeds evil. That is when remorse, confession, atonement, reconciliation, and justification become the “five furies” that seek to avenge moral truth in the face of mauvaise foi . False remorse can facilitate repetition of the evil deed: self-anesthetization is a temporarily effective if ultimately destructive means of drowning out remorse. Confession can be an acknowledgement of guilt or an exercise in self-justification, the difference being that the latter usually results in a compulsive need to repeat the story over and over in a kind of morose delectation not far removed from today’s “tell-all” talk shows.

When atonement is attempted without acknowledgement of the real ethical debt, conscience becomes a kind of moral “loan shark,” compelling us to “pay pain after pain, price after price in a cycle that has no end because we refuse to pay the one price demanded.” Shared guilt is often a form of pseudo-reconciliation, binding together those who would build new world orders”from the Thousand Year Reich to “tolerant” approaches to “sexual diversity””in their need to reconcile the people of the world to themselves. Justification then means subverting reality to one’s desiderata, rechristening the latter as “reality” and then claiming that it demands respect and even legal protection.

For whom is this book written? On one level, it’s wildly out-of-sync with the times, defending such ideas as moral knowledge and design, which contemporary philosophy has long believed to be dead and buried. The book has other eccentricities, as well. Some chapters are argued in philosophical prose. Others, such as the chapter on “objections” to the claim that we can be certain of at least some moral knowledge, are written in dialogue form, opening the way for hostile critics to suggest that Budziszewski constructs and demolishes his own straw men. Yet despite these quirks, Budziszewski’s engaging style and intellectual rigor suggest that his primary audience is students”that is, those who most need and crave intellectual immunization against orthodox relativism. And for them, Budziszewski’s commonsense approach to moral phenomena is perfectly suited. All too often higher education today deems its task to be the production of epistemological agnostics and moral nihilists. What We Can’t Not Know provides young people with the argumentative ammunition they need to resist that juggernaut.

John M. Grondelski was formerly Associate Dean and Associate Professor of Christian Ethics at the School of Theology, Seton Hall University.