Self-Reference and Correspondence. How Constructive is Our Knowledge? Basing on scientific results Radical Constructivism and Evolutionary Epistemology claim to be able to answer the question concerning the epistemological status of our knowledge — but they arrive at opposite conditions regarding the constructive or realistic character of our worldview. A critical discussion of these two positions reveals that they don't satisfy their own demands. The limits of an exclusively scientifically based epistemology are getting obvious when we bring up the genetic epistemology of Jean Piaget who ties the knowledge of the world down to acting in the world, which brings the actor back into epistemology and transcends the realm of science. This discloses at the same time the insufficiency of a bipolar questioning that turns constructivism and realism into an unsuperable antogonism. In a concluding reflection the necessity of a sociological enlargement of the analysis of the process of knowledge is being established.