Karl Otto Apel was born in Düsseldorf in 1922 and died in Taunus on May 15 2017. He was a professor at the universities of Kiel, Saarbrücken and Frankfurt am Main and he worked on issues of language and linguistic communication. Agreeing with Habermas, Apel thought that the foundations of a community of communication could be established which, while still maintaining the need for hermeneuthics, could be adjusted to some principles of critical rationalism. Apel believed, against Kant, that the a priori of the deep structure of reason is neither the possibility of knowledge nor the universality of science, but language.
Apel called it the ‘a priori of the communication community’ which, on the one hand, makes possible a real communication that does not exclude conceptual schemes in the ideal communication and, on the other hand, ensures the inter validity of knowledge allowing for the foundation of ethics.