Methodology of science records existing rules in science. There are general rules for all the sciences and specific rules for different branches of science. The latter are changing over time. These rules (principles of rationality, idealization, simplicity, independent verification, correspondence etc.) may be treated as conclusions from observations on development of science. Evaluating scientific theories by these rules allows us to draw a line of demarcation between science and nonscience. A lot of psychological theories do not much these discussed principles. That is the reason for a perma¬nent crisis in psychological science.