What can we know? Sooner or later, anyone who wants to seriously engage in science will encounter Kant's famous fundamental question. The theory of science deals with the goals, methods, and basic assumptions of science. It reflects on the nature of knowledge formation and engages with the question of what constitutes scientific validity. What role do truth and objectivity play in relation to our hypotheses and theories? Where are the boundaries of knowledge? What distinguishes the inductive from the deductive method of scientific inquiry? These are some of the core questions of the theory of science. All introductory works on the market regarding the theory of science refer to science as a whole.