In his report, the author examines the science of psychology with an unusual perspective – as the science of variability, which generates variable concepts. He puts emphasis on the first underestimated works carried out on a par with the problems highlighted by Bernstein Severtsev, Leontiev, Rubinstein, Blonsky, Vernadsky, Bergson, Berg and others. The article highlights the main challenges of the historical and evolutionary approach of social constructivism: a selection considering the class of purposeful activity as a universal form of life existence, the allocation of the communicative discourse categories of activity, which is interpreted as the basis for the existence of biological, social and psychological systems. The concept of activity as a process of generating diversity at various levels of the system is disclosed. The works of such scholars as Gurevich, Batkin, Gergen, etc. that help to see how the evolutionary significance of diversity are mentioned. The higher one rises through evolution, the more divergent model programs of his/her behaviour are, and there appears a set of variable programs. The author shows that through the activity approach many phenomenological issues of culture are perceived, the development of cultural activity paradigm leads to the fact that psychology goes beyond the scope of a separate science, and serves as a unique paradigm of the future. Since the A.N. Leontiev veiwed psychology as a kind of workshop to support diversity, where the psychologist is as an expert in designing new worlds. The author concludes that the research of activities by which the development of diversity in this world of uncertainty is meant is incredibly important.