The article considers the problem of a rational reconstruction K. Popper’s concept of the methodology of science. The notion of rational reconstruction includes such aspects of scientific rationality as logicality, methodological, axiological and purposeful aspects of investigation. They are reconstructed conventional approach to the construction of the theory of scientific method, which is based on the choice of the values of freedom of scientific research, while maintaining empirical research. The concept of the method of rational discussion emphasizes the concept of an objective ideal tool rational criticism. Because the experience is understood as a method of differences one theoretical system from another, insofar the theory of knowledge of empirical science is conceptualized as a theory of empirical method. Since the «basic» statements are accepted as withstood the test at the moment of state of scientific debate, insofar opening of a new scientific fact is proposed as convention regarding admission statement, it expresses, in the category of scientific statements.