Hans Küng

1. Introduction

Hans Küng (1928–2021) was a Swiss Catholic priest and theologian whose work reshaped late‑20th‑ and early‑21st‑century debates about Christian doctrine, religious authority, and the role of religions in a globalized world. Active primarily in the post–World War II era and formed by the Second Vatican Council (Vatican II), he sought to articulate a form of Christian faith that could remain intellectually credible, ethically responsible, and dialogically open in modern pluralistic societies.

Küng is widely associated with three interconnected projects: a historically conscious reform theology within Roman Catholicism; a sustained critique of infallibilist and authoritarian models of church authority; and the proposal of a “global ethic” (Weltethos) grounded in convergent moral insights of world religions and secular humanisms. His writings span systematic theology, philosophy of religion, ecclesiology, comparative religion, and political ethics.

Sympathetic readers often portray him as a bridge figure between church and modernity, and between Christianity and other religions. Critics within ecclesiastical and academic circles, however, have questioned both his interpretations of Catholic doctrine and his claims about cross‑cultural moral consensus. Debates surrounding his work have made him a reference point for discussions of religious pluralism, the rationality of faith, and the ethical responsibilities of religious institutions.

This entry examines Küng’s life and historical setting, the phases of his intellectual development, his major writings and projects, his core theological and philosophical ideas, his methodological commitments, and the reception—both positive and critical—of his attempt to link Christian theology with a universalizing ethical vision for global politics and civil society.

2. Life and Historical Context

Küng’s life intersected with key upheavals in European and global history, which shaped the questions he pursued. Born in Sursee, Switzerland, in 1928, he grew up during the crises of the Great Depression, fascism, and World War II. Commentators often suggest that the moral catastrophes of the mid‑20th century fostered his later insistence on responsibility, peace, and human rights.

2.1 Biographical Milestones

2.2 Ecclesial and Intellectual Setting

Küng’s career unfolded against the backdrop of Vatican II’s program of aggiornamento (“updating”), Cold War rivalries, decolonization, and accelerating globalization. The Council’s emphasis on religious liberty, ecumenism, and dialogue with modern culture formed the immediate framework for his early ecclesiological and Christological work.

At the same time, he worked within German‑speaking academic theology, where historical‑critical methods, existential and hermeneutic philosophy, and social theory shaped debates about faith and modernity. Observers frequently note that his conflicts with the Roman Curia mirrored wider post‑1968 contestations over authority and democratization in church and society.

From the 1980s onward, the rise of religious pluralism as a public issue, together with intensified global economic and political interdependence, provided the historical horizon for Küng’s shift toward world religions and a global ethic.

3. Intellectual Development

Küng’s intellectual trajectory is often described in distinct but overlapping phases, corresponding both to his biographical situation and to changing global concerns.

3.1 From Neo‑scholasticism to Historical Consciousness

In his early formation (1948–1962), Küng was trained in Thomistic and neo‑scholastic theology in Rome, while also encountering modern philosophy in Paris. Scholars note that this dual exposure led him to seek a theology loyal to the Christian tradition yet open to historical‑critical exegesis and contemporary thought. His early work on the doctrine of the Church already shows an effort to reinterpret dogma historically rather than as timeless propositions.

3.2 Vatican II and Reform Theology

As a peritus at Vatican II and young professor at Tübingen (1962–1971), Küng developed a programmatic reform theology. Works of this period, such as Konzil und Wiedervereinigung and Die Kirche, interpret the Council as a mandate for ongoing structural and doctrinal renewal. Commentators often see here his emerging emphasis on dialogue, service, and the church’s responsibility to the world.

3.3 Conflict, Ecclesiology, and Authority

The controversies around Unfehlbar? Eine Anfrage (1971) and the removal of his missio canonica in 1979 mark a second major phase. His focus turned more explicitly to questions of authority, dogma, and conscience, in conversation with political theory and critical social thought. Some interpreters view this period as radicalizing his earlier reform commitments; others see it as a consistent development of his Vatican II hermeneutic.

3.4 World Religions and Global Ethic

From the 1980s through roughly 2000, Küng expanded his horizon beyond Christian intra‑debates to large‑scale studies of Judaism, Christianity, Islam, and world religions in general. Parallel to this, he formulated the Weltethos project, arguing for convergent ethical norms across traditions.

3.5 Late Interdisciplinary Engagements

In his later years, he engaged questions of science, cosmology, bioethics, and the future of the church, integrating autobiographical reflection with interdisciplinary dialogue. Analysts typically interpret this as a consolidation of his life‑long attempt to hold faith, reason, and global responsibility together.

4. Major Works and Projects

Küng’s corpus is extensive; a number of works are widely regarded as landmarks for understanding his thought.

4.1 Systematic and Doctrinal Works

4.2 Authority and Infallibility

The short but influential Infallible? An Inquiry (Unfehlbar? Eine Anfrage, 1971) critically examines the Catholic doctrine of papal infallibility. Supporters consider it a careful historical and theological reassessment; critics judge it a challenge to magisterial coherence.

4.3 World Religions Trilogy

These volumes aim to combine historical scholarship with constructive proposals for interreligious understanding.

4.4 Global Ethic and Institutional Projects

Works such as Global Responsibility: In Search of a New World Ethic (Projekt Weltethos, 1991) and A Global Ethic for Global Politics and Economics (1997) formulate his moral‑political vision. The 1993 “Declaration Toward a Global Ethic,” presented at the Parliament of the World’s Religions, crystallized this project.

The Global Ethic Foundation (Stiftung Weltethos), established in Tübingen, institutionalized research, education, and dialogue around these themes, collaborating with political bodies, NGOs, and religious organizations.

5. Core Theological and Philosophical Ideas

Küng’s central ideas revolve around the nature of Christian faith, the structure of religious authority, and the possibility of shared ethical norms in a plural world.

5.1 Fallibility and Critical Accountability

Against any claim to exempt status for doctrinal propositions, Küng argues that all human formulations about God are historically conditioned and therefore fallible. This applies, in his view, to papal and conciliar statements as well as to academic theology. Proponents of his approach regard this as aligning theology with modern epistemology; detractors fear it undermines doctrinal stability.

5.2 Rationality of Faith

Küng maintains that faith is not irrational submission but a responsible, existential trust that can be argued for in dialogue with philosophy and science. In Does God Exist?, he interacts with classical proofs, modern critiques, and existential questions to defend belief in God as a rational option. Some philosophers welcome his attempt at “public” theology; others consider his arguments insufficiently rigorous or overly dependent on Christian presuppositions.

5.3 Christology and Discipleship

In On Being a Christian, Küng presents Jesus as the decisive norm for Christian life, emphasizing discipleship, praxis, and following Christ in solidarity with the marginalized. Supporters highlight the ethical and existential orientation of this Christology; more traditionalist critics argue that it risks sidelining metaphysical formulations of Christ’s divinity.

5.4 Church as People of God and Servant Community

Küng conceives the church less as a juridical institution and more as a community of believers called to service, dialogue, and openness to reform. This ecclesiological vision supports democratic participation, transparency, and ecumenism. Admirers see it as faithful to Vatican II; opponents contend it weakens hierarchical structures considered essential in Catholic teaching.

5.5 Global Ethic as Minimal Moral Consensus

Philosophically, Küng proposes that diverse religious and humanist traditions share a “minimal ethic” centered on human dignity, non‑violence, justice, truthfulness, and gender equality. He presents this not as a new religion but as a foundational set of norms capable of undergirding global law and politics. Advocates find here a promising basis for cosmopolitan ethics; critics argue that the extent and depth of such consensus remain contested.

6. Methodology: Faith, Reason, and History

Küng’s methodological stance is a key to understanding his work across theology, philosophy, and ethics.

6.1 Historical‑Critical Orientation

Küng treats Christian doctrines as historically developed responses to experiences of faith, shaped by specific cultural contexts. He makes extensive use of historical‑critical exegesis and church history to reinterpret dogmas. Supporters regard this as enabling responsible reform; critics argue that such historicization risks relativizing revealed truth.

6.2 Correlational Approach to Faith and Reason

Methodologically, Küng rejects both fideism (faith without critical reason) and rationalism (reason excluding faith). He works with a correlational model: human questions—about meaning, guilt, death, and hope—are placed in dialogue with Christian answers. In Does God Exist?, this appears as a systematic engagement with philosophical skepticism, scientific cosmology, and existential doubt before presenting a theistic response.

6.3 Public Rationality and Interdisciplinary Dialogue

Küng insists that theological claims must be articulated in a way accessible to non‑believers and tested in interdisciplinary conversation—with philosophy, natural sciences, and social sciences. This “public” methodology aims to make theology a partner in broader intellectual life. Some scholars see parallels with Jürgen Habermas’s notion of post‑secular dialogue; others argue that Küng underestimates tensions between confessional commitments and secular rationality.

6.4 Hermeneutics of Reform

A further methodological feature is his hermeneutic of aggiornamento: tradition is neither abandoned nor repeated unchanged, but critically retrieved and updated. For Küng, Vatican II exemplifies this model. Proponents consider this faithful to early Christian and patristic developments; opponents maintain that his application of reform goes beyond what conciliar texts warrant.

7. Global Ethic and Political Relevance

Küng’s global ethic (Weltethos) concept connects religious thought with international law, human rights, and global governance.

7.1 Basic Thesis

His oft‑cited formula is:

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“There will be no peace among the nations without peace among the religions. There will be no peace among the religions without dialogue among the religions.”

— Hans Küng, Projekt Weltethos

From this, he infers that a minimal set of shared ethical principles is required for peaceful coexistence in a religiously plural world. He identifies core norms: commitment to human dignity, non‑violence, economic justice, truthfulness, and equal rights for men and women.

7.2 The 1993 Global Ethic Declaration

At the 1993 Parliament of the World’s Religions in Chicago, a “Declaration Toward a Global Ethic,” largely drafted by Küng, was endorsed by representatives of many traditions. Supporters interpret the document as evidence of cross‑religious convergence on basic moral values; skeptics note that signatories often represented liberal currents and that grass‑roots acceptance remains diverse.

7.3 Political and Economic Dimensions

In A Global Ethic for Global Politics and Economics, Küng extends the project to international relations and market structures, arguing that unchecked economic globalization and power politics require ethical constraints grounded in widely acceptable norms. Political theorists and policy practitioners have engaged his proposals in discussions of cosmopolitan democracy, sustainable development, and corporate responsibility, sometimes praising their moral clarity and sometimes questioning their institutional feasibility.

7.4 Reception and Critique

Proponents within international organizations and NGOs see the global ethic as a useful soft‑law framework informing charters and educational programs. Critics argue that:

• the identified norms may reflect Western liberal priorities more than truly global consensus;
• emphasizing moral agreement might obscure deep doctrinal and cultural conflicts;
• ethical language without binding institutions risks remaining merely aspirational.

Despite such debates, Küng’s project is frequently cited in discussions about religion’s constructive role in global civil society.

8. Engagement with World Religions

Küng devoted several decades to extensive study of non‑Christian religions, particularly Judaism and Islam, as well as to broader comparative work.

8.1 Methodological Assumptions

He approaches religions as historically evolving traditions that respond to fundamental human questions. Rather than ranking them, he seeks to understand each on its own terms while also exploring possibilities for ethical convergence. This stance is often described as inclusivist: he upholds the distinctiveness of Christian faith while recognizing genuine truth and salvation in other traditions.

8.2 Judaism

In Judaism: Between Yesterday and Tomorrow, Küng presents Judaism as Christianity’s “elder brother,” tracing shared roots and later divergences. He strongly rejects Christian anti‑Judaism and argues for a theological recognition of Judaism’s ongoing covenantal status. Jewish and Christian scholars have welcomed his critique of supersessionism, though some Jewish readers question whether his framing remains ultimately Christian‑centric.

8.3 Islam

In Islam: Past, Present and Future, he offers a detailed historical and theological survey, emphasizing both commonalities (monotheism, prophetic tradition, ethical concerns) and differences (view of Muhammad, scripture, law). He argues that dialogue with Islam is crucial for world peace and that stereotypes must be replaced by informed understanding. Many Muslim and Western scholars appreciate the breadth of his treatment, while some Muslim critics perceive misunderstandings or contest specific theological judgments.

8.4 World Religions and Pluralism

Küng’s broader work on world religions underlies his global ethic thesis. He contends that despite doctrinal divergences, religions share core ethical imperatives. Proponents of religious pluralism see his approach as a constructive middle path between relativism and exclusivism. Critics from more exclusivist Christian and non‑Christian positions argue that his model downplays irreducible truth‑claims; some philosophers of religion question whether ethical overlap suffices to ground robust pluralist theory.

9. Debates with Ecclesiastical Authority

Küng’s most visible controversies concern his relationship with Roman Catholic magisterial authority, especially around papal infallibility and church structure.

9.1 Critique of Papal Infallibility

In Infallible? An Inquiry, Küng re‑examines the First Vatican Council’s 1870 definition of papal infallibility. He argues historically that the dogma emerged within a particular 19th‑century context and theologically that no human office can be absolutely immune from error. Supporters hold that this restores a more collegial and scriptural ecclesiology; church officials and many theologians respond that his interpretation is incompatible with authoritative Catholic teaching.

9.2 Withdrawal of the Missio Canonica (1979)

After protracted exchanges with the Congregation for the Doctrine of the Faith, the Vatican withdrew Küng’s license to teach as a Catholic theologian at Tübingen. He remained a priest and a university professor, but no longer under ecclesial mandate.

9.3 Ongoing Tensions and Dialogue

Küng continued to criticize centralized papal authority, clericalism, and lack of internal democracy, advocating structural reforms such as bishops’ collegiality and greater lay participation. He also engaged in occasional personal correspondence and public exchanges with popes, including John Paul II and Benedict XVI, sometimes stressing shared concerns (e.g., for peace, dialogue) while maintaining sharp disagreement on governance and doctrine.

Some theologians view his stance as a prophetic challenge necessary for reform; others consider it a persistent source of polarization. Within broader Catholic debates, his case has become emblematic of tensions between critical theology and hierarchical oversight in the post‑Vatican II church.

10. Impact on Philosophy of Religion and Ethics

Although primarily a theologian, Küng has been an important interlocutor for philosophers of religion and ethicists.

10.1 Rationality of Theism

In Does God Exist?, Küng surveys classical theistic proofs, Kantian critiques, and modern existentialist and analytic objections. He proposes a form of “fundamental trust” in reality as the precondition for both science and faith, arguing that theism offers a coherent grounding for this trust. Philosophers sympathetic to religious existentialism and hermeneutics have welcomed this as a sophisticated alternative to both evidentialism and atheism. Analytic philosophers have sometimes criticized the work for lacking precise argumentation by their standards, though they often acknowledge its breadth of engagement.

10.2 Ethics, Human Rights, and Global Justice

Küng’s global ethic project has influenced discussions in political philosophy, international law, and applied ethics. His claim that religions can underwrite a cross‑cultural foundation for human rights, democracy, and economic justice has been cited in debates about cosmopolitanism and global governance.

Proponents argue that his work provides a narrative and motivational depth often missing in secular accounts of rights. Critics contend that rights can be grounded without appeal to religion and that his consensus model may obscure power asymmetries.

10.3 Pluralism and Interreligious Philosophy

Küng’s comparative studies and pluralist orientations have contributed to philosophical discussions on religious diversity, supporting views that see multiple traditions as bearers of partial truth. Some philosophers of religion align his stance with “inclusivist” or “convergent” models; others argue that his emphasis on ethical convergence sidelines metaphysical and soteriological disagreements.

Overall, his work has encouraged greater engagement between theology and secular philosophy, particularly around questions of global ethics and the public role of religion.

11. Criticisms and Controversies

Küng’s prominence has generated substantial criticism from different directions—ecclesial authorities, fellow theologians, philosophers, and representatives of other religions.

11.1 Intra‑Catholic and Ecclesial Critiques

Within the Catholic Church, leading officials and many systematic theologians have argued that Küng’s positions on papal infallibility, church authority, and moral questions conflict with magisterial teaching. They contend that:

• his fallibilist view of doctrine undermines confidence in the church’s teaching office;
• his ecclesiology underestimates the theological role of hierarchy;
• his emphasis on conscience may relativize objective moral norms.

Supporters respond that he remains within a reformist, not revisionist, trajectory of Catholic tradition, appealing to Vatican II’s spirit.

11.2 Academic Theological Critiques

Even among sympathetic scholars, some question aspects of Küng’s method and conclusions. Historical theologians have debated his readings of councils and doctrinal development, occasionally judging them selective. Systematic theologians from various confessional backgrounds sometimes argue that his drive for accessibility leads to doctrinal simplification.

11.3 Philosophical and Ethical Critiques

Philosophers of religion have raised concerns about the rigor and structure of his arguments for God’s existence, especially when measured against analytic standards. In ethics and political theory, critics of his global ethic project argue that:

• the supposed cross‑cultural consensus may be more aspirational than descriptive;
• normative universals risk marginalizing local traditions and minority voices;
• the project can be co‑opted for “civil religion” or soft power purposes.

11.4 Interreligious Concerns

Jewish and Muslim scholars, while often appreciative of his irenic intentions, have sometimes noted asymmetries in his treatment of their traditions, suggesting that Christianity still functions as the implicit norm. More exclusivist Christian and non‑Christian thinkers argue that his pluralist leanings relativize unique truth‑claims.

Despite these critiques, many observers agree that the controversies themselves have sharpened debates about authority, pluralism, and global ethics.

12. Legacy and Historical Significance

Küng’s long career left a multifaceted legacy in theology, interreligious relations, and global ethics.

12.1 Reform Catholicism and Ecclesial Debates

Within Catholicism, he is widely seen—positively or negatively—as a key figure of post‑Vatican II reform. His critique of infallibility and advocacy of participatory church structures have influenced generations of theologians, clergy, and lay movements concerned with transparency, collegiality, and the role of conscience. Even critics acknowledge that his work helped define the parameters of acceptable theological dissent and highlighted unresolved tensions in conciliar reception.

12.2 Interreligious Dialogue and Global Civil Society

Küng’s large‑scale studies of Judaism, Christianity, and Islam, along with his involvement in Christian‑Jewish and Christian‑Muslim dialogue, contributed to a climate of greater mutual understanding. The Global Ethic project and associated institutions (such as the Global Ethic Foundation) have had sustained impact in educational curricula, NGO initiatives, and certain international forums, where his formulations continue to inform discourse on religion’s role in peacebuilding and human rights.

12.3 Influence Beyond Theology

In broader intellectual history, Küng is often grouped with thinkers who sought a constructive engagement between religion and modernity rather than withdrawal or confrontation. His attempts to argue for the rationality of faith in conversation with philosophy and science, and to ground universal ethics in cross‑cultural religious resources, have been taken up—not always uncritically—by philosophers, political theorists, and practitioners in diplomacy and business ethics.

Assessments of Küng’s overall historical significance differ: some portray him as a pioneering architect of a post‑conciliar, globally engaged theology; others see him as representative of a particular liberal reform current whose long‑term outcomes remain uncertain. Nonetheless, his work continues to serve as a major reference point for debates on the future of Christianity, religious pluralism, and the ethical foundations of a global order.