1. Frankfurt School and beyond

The Frankfurt School with protagonists Adorno, Horkheimer, and Herbert Marcuse is the cornerstone of critical social sciences and gained worldwide attention in the wake of the student movements of the last century. Habermas was generally seen as a second-generation Frankfurt School representative but, in many respects, goes beyond their thinking, for example, does not adhere to their pessimistic views on cultural development and the almost inescapable dominance of capitalism. Most importantly, Habermas shifts the theoretical grounds of social theory to language and communication and, in this, finds both normative standards for enabling the good society and a space for rehabilitating reason in its practical use in social interaction and everyday life. He sought to revive a trust in reason that, in the face of the experience of the Holocaust and Fascism, had been buried in the bleak critique of the ‘Dialektik der Aufklärung’ (Dialectic of Enlightenment) of Adorno and Horkheimer. With Habermas’s works covering the diverse grounds of post-national identity, normative law, the role of religion in secular societies, bioethics, the politics of historiography, and many more, what stands out in his oeuvre is his theory of communicative reason. The idea of communication as the brain, the heart, and the bloodstream of social life builds up over time to his multi-level theory of rationality and society.

2. Communicative action and discourse ethics

This engagement starts with his early insights into language and epistemology, including the critical analyses of Schelling and Heidegger. The 1962 Habilitation thesis Strukturwandel der Öffentlichkeit (Structural Transformation of the Public Sphere) outlines the development of the public sphere as the constituens of civil society. The public sphere, emerging from private opinion-forming circles in eighteenth-century Europe that were not penetrated by the feudal state, allows for a critique and at least discursive control of state institutions and their political and economic decisions. As the realm of reasoning, the public sphere is seen as a prerequisite of the constitutional state (and, of course, under attack by particularities of all sorts and hegemonic power games). Habermas acknowledges his debt to Kant in deploying the idea of publicity. He also took to heart Kant’s distinction between the permitted limited use of private reason and the free use of reason in the public sphere of scholarly and well-informed debate.

In his 1981 opus magnum Theorie des kommunikativen Handelns (Theory of Communicative Action), critical thinking, systems theory, the appropriation of linguistic models, and the quest for grounding societal consensus in rationality culminate in a framework for social pragmatics and deliberative reasoning. Here, consensus-oriented communicative action, rooted in the rational agreement based on validity claims, is contrasted with strategic action which is also rational but rooted in the distributions of power and economic interests. At times, this reflexive theory and the critique of functionalist reason it implies have been misunderstood in a programmatic or objectifying way as a moral manual for implementing discursive rules. Instead, it needs to be understood as the normative theory of an ideal speech situation that identifies the preconditions – such as fairness, veracity, and equality – for enabling ‘discourse free of domination’ and permits ‘the unforced force of the better argument’ and, as a consequence, for emancipatory processes to emerge.

The mutual recognition of these norms of the human capacity to deliberate and pursue rational interests is at the core of this concept. Proceeding from communicative reason means that its public use is part of the very concept of reason; reason is not simply intellectual self-control and confined to an inner monologue of the subject but a property of any communicative action which does not force or try to manipulate the communicative other into submission but tries to convince them by means of argumentation. As with Kant, the adherence to truth is carried through to social intercourse.

Habermas’s turn to the ethics of discourse had helped a move away from the Marxist critique of ordinary language use as the realm of ideology and simultaneously opened up critical theory towards pragmatics and linguistic philosophy (and vice versa) and also marked a shift from the cultural pessimism of the early Frankfurt School to a more liberating light at the end of the tunnel. This results ultimately in a relational theory of society and politics where legitimacy is based on reciprocal recognition and conflicting interests need to be sustained by the interchange of arguments. Grounding the mitigation of conflicting positions in validity claims is what distinguishes this from what Habermas called a ‘post-truth democracy’ in which actors would merely try to balance conflicting strategic interests in order to keep them from escalating but not need to share a common understanding of what constitutes a society.

3. In defence of democracy – and the project of modernity

At the beginning of World War II, Habermas was 10 years old; at its end, he was 16; the post-war years and the transition from dictatorship and the most inhumane period in world history to a parliamentary democracy integrated into the West shaped Habermas’s political awareness and his lifelong pursuit of democratic goals. In contrast to the pessimism of the Frankfurt School and later postmodern critics, he holds on to the notion of modernity and enlightenment and sees them as an ongoing task rather than a failed path. In his view, modernity had not come to an end – neither with the instrumental side of rationality turning against the human project nor with the relativist claims of postmodernity or the proclaimed ‘end of history’. For Habermas, the ‘unfinished project’ of enlightenment and modernity requires correction and continuous efforts rather than abandonment.

4. Without contraries, there is no progression

In a concrete and very political sense, the pursuit of democracy manifests itself in Habermas’s many interventions in public debates. Although one might be tempted to classify them into more scholarly – such as the Positivismusstreit, the Habermas-Luhmann-Debatte, or the Historikerstreit – and more political ones – such as the writings on eugenics or the fate of European integration – this distinction does not really hold. In each of Habermas’s writings, theory and the ambition of making a societal impact are intertwined: the political stance rests on theoretical foundations, and the theory aims at a framework for an open society in which rational decisions can be taken without rejecting ethics and a sense of responsibility.

In the many socio-philosophical controversies in which Habermas engaged, he emphasises the ethical responsibility of scientific work and of epistemological positions, and he argues against a science that confines itself to mere observation and positivism.

A fine example of this is Habermas’s review of Martin Heidegger’s ‘Einführung in die Metaphysik’ in the conservative newspaper Frankfurter Allgemeine Zeitung in 1953. Heidegger had just published his 1935 lecture text without feeling the need to remove or comment on his affirmative words regarding the National Socialist movement. Habermas criticised this persistence of undemocratic thought and the continuation of careers in post-war Germany; he did not rebuke Heidegger’s philosophy but argued ‘with Heidegger against Heidegger’ – and publicly attacked the dominant German philosopher of this time. This bold intervention, undertaken as a 24-year-old student, not only indicates how important the democratic transformation of Germany was to the young scholar, but it also demonstrated his willingness to challenge established figures and thought and paved the way for his future contributions to public debates over the next seven decades.

5. Against relativist historiography

In keeping with this very early intervention is Habermas’s contribution to the so-called Historikerstreit (historians’ debate) which took place in the 1980s, with Habermas sharply rebuking conservative historians for attempting to re-evaluate the past with a view to ‘overcoming’ the dark shadow of Hitler. The debate centred on the Federal Republic’s historical interpretation of National Socialism as to whether Germany had taken a Sonderweg (special path) and as a result the Holocaust could be seen as a crime of unique evil, or rather whether it should be explained in its historical context and should also be seen in comparison with and as a reaction to other totalitarian regimes. Connected to this was the question of what role the acknowledgement of the Nazi past and collective guilt should continue to play in German political and national identity. Habermas insisted on the singularity of the Holocaust and criticised the relativist turn as an effort to dispose of the past (Entsorgung der Vergangenheit) that risked ‘normalising’ National Socialism and undermining the moral-political consensus of the Federal Republic.

By opposing attempts to historicise and so relativise Nazi crimes, Habermas sought to preserve a normative horizon that anchors identity in constitutional patriotism (Verfassungspatriotismus) rather than a narrative of positive nationalism. In that sense, the debate revealed how national historiography and the politics of memory directly feed into concepts of citizenship. Acknowledging historical injustice, adopting collective experience and responsibility, and being grateful to other nations that went to war to fight German Fascism can be a heritage and become part of democratic self-reflection that defines a society in a positive and, literally, constructive way.

6. Ach, Europa!

Habermas’s support for supranational democratic institutions stemmed from his concern that globalisation has outpaced the regulatory capacities of the nation state. Economic interdependence and transnational crises require governance structures that exceed national frameworks. However, Habermas insisted that such structures must be democratically legitimised. His advocacy of a stronger European Parliament and a shared supranational public sphere reflects an attempt to align institutional design with the principles of discourse ethics. His support for a united Europe was not merely procedural but rests on the idea that shared norms must emerge from inclusive public deliberation rather than technocratic imposition.

His partiality for Europe is not uncritical. During the Eurozone crisis in the early 2000s, Habermas became one of the most vocal critics of what he perceived as a technocratic drift of governance. Decision-making processes, dominated by executive bodies such as the European Council and informal negotiations among national leaders in support of mainly economic goals, appeared to ignore democratic deliberation. This tension reveals a central dilemma: the EU is both the most advanced realisation of post-national democracy and a site where democratic deficits are acutely visible, for example, in the absence of a European public sphere capable of sustaining transnational deliberation. The emergence of a distinctively European public sphere was for him aimed at enhancing global cooperation and legal-political cooperation. It was intended to advance better global governance through a peaceful steering of economic and political relations. Habermas did not admit a tension between his Europeanism and his cosmopolitanism, though his many commentators were not sure about this.

7. By virtue of language

Habermas’s intellectual style has been marked by a dialectical openness and precision in language. While in the tradition of his mentor Adorno, Habermas departs from negative dialectics by a willingness to appropriate insights from diverse traditions. His engagements, for example, with John Searle, Charles Sanders Peirce, Noam Chomsky in linguistics, or John Rawls on social justice exemplify a mode of theorising that is neither derivative nor eclectic. Rather, it is integrative in a critical sense: external frameworks are subjected to reconstruction within his own theory.

This approach is greatly in evidence in his monumental final work Auch eine Geschichte der Philosophie (Also a History of Philosophy) which appeared in German in two volumes in 2019 and has only recently appeared in three volumes in English. In these volumes, Habermas reconsiders the relationship between faith and knowledge in the light of the completion of his own post-metaphysical and detranscendentalised philosophy. Earlier philosophers are seen, in a fashion influenced by Hegel, as developing positions which culminate in his less metaphysically complete synthesis of Kant’s, Hegel’s, and Marx’s philosophies, drawn together by the pragmatic standpoint influenced by Peirce and the linguistic philosophy exemplified by Herder, mediated by Wilhelm von Humboldt and the linguistic philosophers of the twentieth century. The encyclopaedic range of his thinking was extraordinary. He attempted valiantly to include non-Western religions and philosophies in an epic story of struggles from what he calls the Axial Age in the human condition and our self-wrought triumphs and disasters. His eyes were always on the future, envisaged in a Kantian fashion as a Reich der Zwecke (kingdom of ends) but impeded in its arrival through the shortcomings of a world economy guided by naked self-interest and dangerously rivalrous big states. In seeking to achieve such a better future, Kant had recognised the importance of drawing upon religious beliefs and practices which, though not necessarily open to scientific verification, encouraged people to identify themselves as a potential community.

This methodological openness has enabled Habermas to exert influence across philosophy, sociology, political theory, linguistics, philology, and legal studies. In a hypothetical network graph of contemporary scholarship, his concepts would appear as central nodes, linking otherwise disparate areas of inquiry. Such centrality is not merely a function of citation metrics but reflects a deeper capacity to mediate between paradigms. Habermas’s engagement with others is grounded in a normative commitment: debate, even disagreement, presupposes recognition. Against the indifference of polarising arguments, he models a form of critique that takes the other’s position seriously – which also includes stating differences clearly and not shying away from dissent.

Equally significant is his rhetorical and conceptual precision. Habermas repeatedly introduced formulations that coined phenomena into tractable concepts. Formulations like structural transformation of the public sphere (Strukturwandel der Öffentlichkeit), discourse ethics (Diskursethik), colonisation of the lifeworld (Kolonialisierung der Lebenswelt), modernity as an unfinished project (unvollendetes Projekt der Moderne), constitutional patriotism (Verfassungspatriotismus), radical reformism (radikaler Reformismus), and post-national constellation (postnationale Konstellation) often became hegemonic within academic discourse. Such influence can provoke unease with adversaries; to define the language of debate is to exercise a form of intellectual power, maybe the power of the better concept.

8. With disappointment, tenacity

Throughout his life, Jürgen Habermas defended modernity’s claims to truth and democracy. His ideal of the public sphere now appears besieged by dynamics that invert the normative presuppositions of discourse ethics and seem the opposite of his conception of the public use of reason: the dismissal of factual argumentation, polarisation fuelled by intermediaries and algorithms, the fragmentation of publics into self-asserting bubbles of conviction, the frequent disparagement and dehumanisation of the other in public discourse, the disintegration of the Western alliance, and the rise of a radical right and totalitarian vocalism in so many ‘modern’ countries.

In the face of complacent post-factual politics, unjustified wars, and the spread of radical unreason, Habermas’s disappointment was tangible; still, he remained an insistent and interventionist thinker. In November 2025, he published in the newspaper Süddeutsche Zeitung a last essay with the striking title ‘Von hier an müssen wir alleine weitergehen’, about the unprecedented fissures in the Western democratic alliance, the disturbing path the US has taken under their current leader, and the necessity of upholding a strong and increasingly independent European position as a matter of democratic survival. On the author’s death, the title of this last piece resonates with us in a different way. He left, and the title of his piece ‘From here, we must go on alone’ took on a new meaning. – And go on, we must.