"Theater of the scientific age" is a fundamental term in Brecht´s writings similar to "epic theater" or "non-aristotelian theater". In contrast to these two terms it is scarcely known, but not less important. It arises during the 1930s and can be used to characterize Brecht´s aesthetics as a whole. The lecture will show that the "theater of the scientific age" introduces a concept of artistic modelling which couples the realms of art and science and which functions as the basic principle of theatrical appearing and disappearing.