A short life of the author
Hans Küng (19 March 1928 – 6 April 2021) was a Swiss Catholic priest, theologian, and author who was one of the most influential and most controversial Christian thinkers of the twentieth century — a man who served as an official theological adviser (peritus) at the Second Vatican Council, helped shape the reforms of the 1960s, and then found himself stripped of his authority to teach Catholic theology by the Vatican in 1979 for questioning the doctrine of papal infallibility. His subsequent career as a public intellectual, best-selling author, and advocate for a “Global Ethic” made him the most widely read Catholic theologian in the world — a distinction that the Vatican regarded with unyielding disapproval.
Early Life and Vatican II
Küng was born in Sursee, Switzerland, studied philosophy and theology at the Pontifical Gregorian University in Rome, and was ordained a priest in 1954. He earned his doctorate in theology from the Institut Catholique de Paris with a dissertation on Karl Barth’s doctrine of justification — a work that argued, provocatively, that there was no fundamental disagreement between the Protestant Barth and Catholic teaching on this crucial theological point. The dissertation was published as Justification (1957) and immediately established Küng as a theologian willing to cross confessional boundaries.
In 1960, at age thirty-two, Küng was appointed professor of theology at the University of Tübingen, where he remained for the rest of his academic career. Pope John XXIII appointed him a peritus at the Second Vatican Council (1962–1965), where he was a passionate advocate for reform — liturgical renewal, ecumenism, episcopal collegiality, and the engagement of the Church with the modern world. His colleague and rival at Tübingen was Joseph Ratzinger, the future Pope Benedict XVI, who had been a reformer at the Council but moved steadily rightward in subsequent decades.
The Infallibility Crisis
Küng’s book Infallible? An Inquiry (1970) challenged the doctrine of papal infallibility defined at the First Vatican Council in 1870. Küng argued that the claim that the pope can make infallible pronouncements on faith and morals was historically unfounded, theologically problematic, and an obstacle to ecumenical dialogue. The book provoked a firestorm. After years of warnings and dialogue, the Congregation for the Doctrine of the Faith — headed by Ratzinger — withdrew Küng’s missio canonica (his licence to teach as a Catholic theologian) on 18 December 1979.
Küng continued to teach at Tübingen as a professor of ecumenical theology (a position funded by the university rather than the Church) and continued to say Mass and to describe himself as a Catholic priest. He never left the Church, and the Church never excommunicated him. The stand-off — a Catholic theologian who rejected a central doctrine but remained within the institution — was one of the defining dramas of post-conciliar Catholicism.
Major Works
On Being a Christian (1974) is Küng’s most widely read book — a 700-page work that presents the essential content of Christian faith in language accessible to educated general readers. It sold millions of copies and was translated into dozens of languages.
Does God Exist? An Answer for Today (1978) is a philosophical survey of the arguments for and against God’s existence, engaging with Descartes, Kant, Hegel, Feuerbach, Marx, Freud, and Nietzsche before arriving at a qualified affirmation. It is one of the most comprehensive treatments of the question written in the twentieth century.
Eternal Life? (1982) examines beliefs about death, immortality, resurrection, heaven, and hell across religious traditions.
The Global Ethic Project
In the last decades of his life, Küng devoted himself to the idea of a “Global Ethic” — a set of fundamental ethical principles shared by all the world’s religions that could serve as a basis for peaceful coexistence. The Declaration Toward a Global Ethic, drafted by Küng, was adopted by the Parliament of the World’s Religions in Chicago in 1993. He argued that there could be no peace among nations without peace among religions, and no peace among religions without dialogue.
His trilogy on the world religions — Judaism (1991), Christianity (1994), and Islam (2004) — attempted to present each tradition sympathetically and comprehensively to readers of other faiths.
Critical Assessment
Küng’s admirers regard him as the most courageous and intellectually honest Catholic theologian of his era — a man who paid a professional price for speaking truth to ecclesiastical power. His critics — within the Church — argue that he was a gifted populariser rather than an original theologian, that his challenge to infallibility was more polemical than scholarly, and that his Global Ethic project was well-intentioned but theologically thin.
His significance is undeniable. He forced the Catholic Church to debate questions it preferred to consider settled, he brought serious theology to millions of general readers, and his interfaith work anticipated concerns about religious pluralism and conflict that have only grown more urgent.
Collecting Küng
On Being a Christian (1976, Doubleday, English translation) is affordable and widely available. Infallible? (1971, Doubleday) is of historical interest. German first editions (Piper Verlag) are sought by theology collectors. Küng’s papers are held at the University of Tübingen.
Bibliography
| Title | Year | Publisher | Language |
|---|---|---|---|
| Christianity: Essence, History, and Future Küng's most comprehensive work on his own tradition — the final volume of his Abrahamic trilogy — traces Christianity from Jesus through two thousand years of development, identifying the paradigm shifts that transformed a Jewish sect into a world religion and asking what Christianity must become to survive the twenty-first century. | 1994 | R. Piper & Co. Verlag | English |
| Does God Exist? An Answer for Today Küng's massive philosophical theology — over 800 pages in English translation — engages systematically with the modern critique of religion from Descartes through Nietzsche and beyond, arguing that belief in God is rationally defensible (though not provable) and that atheism requires as much faith as theism. | 1978 | R. Piper & Co. Verlag | English |
| Eternal Life? Life After Death as a Medical, Philosophical, and Theological Problem Küng's examination of the question of life after death engages with medical evidence (near-death experiences), philosophical arguments, and the diversity of religious traditions to argue that hope for eternal life is rationally defensible though unprovable — and that how one answers this question determines how one lives. | 1982 | R. Piper & Co. Verlag | English |
| Global Responsibility: In Search of a New World Ethic Küng's argument for a universal ethic shared across religious and cultural traditions — proposing that the world's religions, despite their doctrinal differences, share common moral principles that could form the basis of a global ethic for an interconnected world. | 1990 | R. Piper & Co. Verlag | English |
| Infallible? An Inquiry Küng's challenge to papal infallibility — published on the centenary of the First Vatican Council's definition of the doctrine — argued that the concept was historically unjustified, theologically incoherent, and practically harmful, triggering a crisis in Küng's relationship with the Vatican that would eventually cost him his license to teach as a Catholic theologian. | 1970 | Benziger Verlag | English |
| Islam: Past, Present and Future Küng's massive study of Islam — over 700 pages — applies the same historical-critical method he used on Christianity to the Muslim tradition, tracing Islam's development from Muhammad through its golden age to its modern crisis, arguing for the possibility of an Islamic reform analogous to the Christian Reformation. | 2004 | R. Piper & Co. Verlag | English |
| Judaism: Between Yesterday and Tomorrow Küng's study of Judaism — the first volume of his trilogy on the Abrahamic religions — traces Jewish history and theology from the patriarchs to the modern state of Israel, treating Judaism not as a mere precursor to Christianity but as a living religious tradition with its own integrity, its own development, and its own contemporary challenges. | 1991 | R. Piper & Co. Verlag | English |
| On Being a Christian Küng's most widely read work — a 700-page attempt to articulate what Christian faith means in the modern world — argues that authentic Christianity requires neither fundamentalist literalism nor liberal dissolution but a return to the radical message of Jesus himself, stripped of later ecclesiastical accretions and dogmatic elaborations. | 1974 | R. Piper & Co. Verlag | English |
| The Catholic Church: A Short History Küng's concise history of Catholicism from Jesus to John Paul II — written for general readers — traces the church's development from a persecuted sect through imperial religion, medieval power, Reformation crisis, and modern retrenchment, arguing that the church must reform or become irrelevant to the modern world. | 2001 | Weidenfeld & Nicolson | English |
| The Church Küng's ecclesiology — written in the wake of Vatican II — argues for a radical reform of Catholic Church structures, proposing a return to the New Testament model of the church as a community of believers rather than a hierarchical institution, and anticipating many of the conflicts with Rome that would mark his later career. | 1967 | Herder Verlag | English |