"Jürgen Habermas, one of the most important contemporary philosophers and social theoreticians, is someone who intervenes in public discourse - but as an analyst not a moralist.
Far from merely publishing for other inhabitants of the celebrated ivory tower of scholarly research, his philosophizing is characterized by an attempt at systematic mediation of thinking and political action. He thereby adheres to the view that rationality is implemented in verbal understanding. That is also the background to his lecture on June the 29th, 2002, at the Berlin-Brandenburg Academy of Sciences, devoted to the question "When Must We Be Tolerant? On Rivalry between Views of the World, Values, and Theories". His speech shows what contradictions we must endure in order to be tolerant, and also that tolerance can only be practiced on the basis of a democratic state founded on the rule of law.
Cognitive Rejection without Practical Consequences
We generally understand tolerance as meaning putting up with divergent convictions. The concept thus contains an element of rejection since we can in fact only demonstrate tolerance towards convictions that we have renounced for good subjective reasons. As soon as we are either indifferent about an alien view or even appreciate the "value" of this other conviction, we do not need to be tolerant. The rejection inherent in tolerance is thus radical. Tolerance is located where non-negotiable fundamental convictions meet and no agreement can be expected. What is expected of a tolerant person is not some unresolvable contradiction between competing convictions. That must be accepted. "At issue is the neutralizing bracketing of specific practical consequences arising out of unresolved interpersonal contradiction" (J. Habermas). In other words, the demand is that no action should be allowed to follow from the collision of competing views.
Potential for Conflict: The Good Takes Precedence over the Just
Anyone who is not "metaphysically restricted" has an easier time with the demand that contradictions between competing views of the world should simply be left open. That becomes problematic for someone who derives an ethos, i.e. personal moral convictions, from a religion. After all every religion lays claim to total structuring of a way of life, orienting itself on an infallible doctrine of salvation which lays down what is good and what bad. A religion thus prescribes how a good life must be led. What is good takes precedence over what is just. For someone who derives his or her personal ethos from religious truths laying claim to universal validity, the burden of tolerance is particularly difficult to bear. As soon as his own ideas about right living are determined by generally binding models of the good or of salvation, there arises a perspective where other ways of life seem not only different but also mistaken. The ethos of the other appears as a question of truth or untruth rather than an assessment of values. That explains the potential for conflict implicit in disputes between religions.
Peaceful Co-Existence: The Just Takes Precedence over the Good
Following that model, religious tolerance does not signify that the adherents of some belief should relativize let alone renounce their own claims to truth and certainty. Instead tolerance calls for limitation of the practical impact of one’s own claims to truth and certainty. The demand is that the way of life prescribed by one’s own religion can only be implemented on condition that the same rights are accorded to all others. What is just takes precedence over what is good, and that precedence manifests itself positively in inter-subjective and supra-confessional recognition of the rules of liberal co-existence - as provided for in democracy and human rights as normative foundations of the constitutional state. So for the individual believer that means he can only implement his own ethos within the boundaries set by civic norms of equality. He recognizes the other as a fellow citizen with equal rights, no matter what his or her religious convictions might be.
The expanded concept of tolerance does not remain restricted to the sphere of religion but can be generally extended to tolerance of others who think differently in any way. Within today’s pluralist societies where the traditions of various linguistic and cultural communities come together, tolerance is always necessary "where ways of life challenge judgements in terms of both existential relevance and claims to truth and rightness" (J. Habermas)"