Starting from the problem of tolerance in a multicultural society, the author undermines the limits of a classical-liberal foundation (negative tolerance) and suggests the need for a new meaning: a positive concern of tolerance implying appreciation of a variety of social cultures and value traditions. On an ethical level, positive tolerance can be grounded in the Discourse Theory, developing the classical Kantian deontological ethics in a transcendental-pragmatic and in a transcendental-hermeneutic sense. In this way, discourse ethics can answer two questions posed by tolerance in a multicultural society: the duty to support all in the pursuit of their ideals and realize positive tolerance as well as its restrictions.