A few years ago I had the chance to have a long conversation with then-Cardinal Joseph Ratzinger in Straubing, a small, beautiful town in Lower Bavaria. Ratzinger was there to celebrate the annual feast day of Germany’s oldest surviving religious confraternity, the St. Salvator Confraternity. In the course of our conversation, I mentioned that the German theologian August Adam once lived and taught in Straubing. Ratzinger was obviously moved. “[Adam’s] book The Primacy of Love was a key reading of my youth,” he said. “It was revolutionary even then.” The key reading of a cardinal is always noteworthy; if that cardinal becomes pope, it acquires special importance. The Primacy of Love is the work of a prescient moral theologian who, while popular in his own time, is little known today outside academic circles. Adam’s books sold thousands of copies, but he was blocked from teaching at German universities because of his controversial views on sexuality. With his first encyclical, Deus caritas est, Ratzinger touches on many of the themes taken up by Adam in The Primacy of Love and other books.

Like Adam, Benedict argues that eros is a divine gift that should be celebrated. Echoing The Primacy of Love, Benedict writes that “eros directs man towards marriage, to a bond which is unique and definitive; thus, and only thus, does it fulfill its deepest purpose.” Such ideas may not seem radical today, but when Adam advanced them in the 1930s, he was a voice in the wilderness. Born in 1884 in the village of Pursruck, August Adam was the younger brother of Karl Adam, a respected theologian who taught at Strasbourg and Tübingen. The elder Adam’s work remains influential today: his The Spirit of Catholicism is still in print. Both Karl and August were priests in the diocese of Regensburg. Adam initially studied with his brother at Tübingen, but to avoid the appearance of nepotism, he finished his degree at Freiburg with the ethicist Otto Schilling. Schilling and Karl Adam encouraged August to seek a second doctoral degree (he needed two in order to teach at a German university) but the local bishop and the Bavarian state education ministry denied permission. The authorities never explained their decision, but it’s likely that Adam was considered too progressive. He took a job teaching at a high school in Straubing, where he remained until 1952. Adam wrote widely for theological journals and, in 1931, published The Primacy of Love, his first and best-known book. Within months, the first printing sold out. Reviews in important German theological journals praised the book as “revolutionary,” and it was eventually translated into several languages.

What was so unusual about The Primacy of Love? Adam’s theology is built on the virtue of love, yet unlike many earlier theologians and most of his contemporaries, he did not separate love from passion. On the contrary, he argued that eros is a manifestation of love: “Eros is not only a demonic power, which destroys, ruins, and captivates all life. It is also a source of energy, which is able to overcome the world. The love between man and woman, which the Creator put in their hearts as one of the mightiest desires...is also one of the greatest power sources of human culture.” This was an unconventional idea in Catholic circles of the 1930s. Most moral theologians viewed sexuality as something essentially dangerous, valuable only insofar as it led to procreation. Adam taught that sexuality could be a source of spiritual power; it was, he thought, a divine gift to be sanctified by charity. “In the field of eros, lust and love encounter each other, the sensual and the spiritual are bound together, filled with energy and power,” he wrote. “Charity is the Christian, baptized eros, which increases the force of natural love, because charity gains its power from supernatural sources. From this disposition, all other moral energies, which we call virtues, flow.” In The Primacy of Love, Adam argued against a moral theology that emphasized chastity as the most important virtue. He called for an end to the kind of catechesis that taught that sins against the sixth commandment were the most serious. There are, he reminded his readers, seven deadly sins, not just one. At the time, words like “immorality” and “impurity” were usually used to describe only sexual sins. Many catechists and theologians seemed to have forgotten the church’s traditional teaching about impurity-that every sin makes us impure because it alienates us from God, the source of life.

To be sure, chastity was important to Adam, but he viewed it as the fruit of love. Without love, the virtue of chastity was worthless. Along with St. Augustine, St. Bonaventure, and St. Francis de Sales, he argued that love has to be the center of church teaching. “A real pedagogue will direct the youth not through chastity to love, but through love to chastity,” he wrote. Like the young philosopher Dietrich von Hildebrand, Adam thought that chastity should be motivated by a healthy reverence for the body rather than the unhealthy shame and fear that were often part of religious education. “It is not the person who ignores sexuality as if he were beyond it but the one who acknowledges it and views it with sanctified eyes who is chaste.” Such views earned Adam his share of critics: conservative church leaders blocked him twice (in 1929 and 1932) from a prestigious professorship in Passau because of “modernist views on sexuality.” The bishop of Regensburg wanted The Primacy of Love to be put on the Index of Forbidden Books, but Karl Adam used his influence to prevent that from happening.

Ironically, the young Bernard Häring, later a prominent critic of Humanae vitae, also denounced Adam’s theology as “too lax.” But a later generation of theologians would endorse and develop the ideas Adam defended. In Deus caritas est, for example, Pope Benedict XVI also seeks to place love at the center of church teaching. Like Adam, he sees sexuality as a divine gift. He invokes the image of marital love to illustrate God’s love for the world: Eros is somehow rooted in man’s very nature; Adam is a seeker who abandons his mother and father in order to find woman; only together do the two represent complete humanity and become one flesh.... From the standpoint of creation, eros directs man towards marriage, to a bond which is unique and definitive; thus, and only thus, does it fulfill its deepest purpose. Corresponding to the image of a monotheistic God is monogamous marriage. Marriage based on exclusive and definitive love becomes the icon of the relationship between God and his people and vice versa. God’s way of loving becomes the measure of human love. Ratzinger also echoes Adam’s notion of the “proper Christian.”

According to Adam, a “proper” (in German, korrekt) Christian is a person who, while fulfilling his ecclesiastical duties, shows no sign of holiness-for example, someone who always attends Sunday Mass, but speaks harshly about his neighbors. (François Mauriac offers a deft portrait of this kind of person in his novel The Woman of the Pharisees.) Adam argued that Christians must fight against the temptation to conform themselves to conventional proprieties. Love has to be at the heart of a Christian’s life, and if that love is to be modeled on Jesus’ love, every cultural accommodation that turns a Christian into a “proper” citizen is a caricature of the gospel. Self-righteous Christians who lack spiritual depth are the best argument against Christianity. It is interesting that in Deus caritas est the pope, too, admonishes us not to become “proper Christians”-a term I’ve never encountered in any of the classical sources. I suspect he got it from Adam’s book, Tension and Harmony: About the Value of Dogma for Personal Life, which was once almost as widely read as The Primacy of Love.

Pope Benedict writes that “proper Christians” do their duties without love, become spiritually arid, and thus lose their attachment to God. As the pope says in Deus caritas est, Christianity is countercultural, antibourgeois, and, above all, radical. In Tensions and Harmony, Adam acknowledges that even priests are tempted by the secure lifestyle of the “proper” Christian: His clothes are proper from the Roman collar down to his shoes-everything exactly according to the directives.... He holds the church in proper order, Mass always starts on time, the homilies are well prepared. He promptly answers and acts if his sheep come to him, but their hearts are never set on fire by him. Everything he does has something impersonal about it, like at the post office, or at the bank. He is “proper” in everything he does...but he lacks a mysterious something, a grain of salt and a speck of ambergris: selfless love. Adam’s courageous witness was not restricted to matters of theology. He was an early critic of the Nazis, arguing that their anti-Semitic ideology was incompatible with church teaching. As a result, he became a target of the regime.

In 1943, the Nazis stopped the publication of his book The Sixth Commandment, and Adam was among those scheduled for execution after the final victory of Hitler’s army. Because of his public resistance to the Nazis, American troops asked him to serve as mayor of Straubing after the Allied victory, but he declined. August’s brother Karl had a less heroic wartime record. Karl was a steadfast monarchist who believed that Hitler would restore order. He viewed the destruction of Catholic societies and unions as a means of bringing about a reformed Catholicism, one freed from the burdens of the past. Karl would not repudiate his error until 1944. As a result, he and August grew estranged. The only correspondence between the two brothers that survives from this period are two postcards. It’s possible that Karl destroyed August’s letters in order to protect his brother from the Nazis, or that August did the same for his brother after the war. Some have suggested that the brothers had weekly phone conversations, but that seems highly unlikely in view of the fact that Karl had been nearly deaf since the 1940s.

Despite the efforts of some of his critics, August Adam was never silenced by the Vatican. Instead, his work was largely ignored. The first official approval of his ideas did not occur until the pontificate of John XXIII, when his work was referenced in a broadcast on Vatican Radio. Pope Paul VI tried to develop some of Adam’s ideas on sexual ethics in Humanae vitae, as did John Paul II in The Theology of the Body. Adam isn’t mentioned by name in either work, but it is not improbable that John Paul, with his excellent command of the German language and his interest in German thought, read some of Adam’s works. We will never know what Adam would have said about either Humanae vitae or The Theology of the Body-or how much of his own influence he would have recognized in them. He died on February 5, 1965, only a few years before his most characteristic ideas began to gain currency and acceptance. He is buried at St. Michael’s Cemetery in Straubing.