The problem of scientific rationality is one of the fundamental challenges in the theory of scientific knowledge. This problem was first clearly articulated by philosophers and scientists of Ancient Greece, who proposed a new understanding of scientific knowledge—namely, not as empirical and practically useful knowledge, as it had been previously understood in the civilizations of the Ancient East, but as rational and logically proven true knowledge. Thus, the concept of scientific rationality was introduced, where scientific knowledge began to be understood as a product not 
of sensory (experiential) cognition, but as a product of thought. This article demonstrates how this understanding of scientific knowledge led to the emergence of the modern understanding of science, where the leading role in the construction of scientific knowledge began to be assigned not to experience, but to thought. This article explores the concretization of general scientific rationality not only in different cultural-historical types of science (diachronic scientific rationality), but also 
in relation to different fields of science, different levels of scientific knowledge, and its types (synchronous scientific rationality). Understanding the complex structure of scientific rationality allows for a more concrete approach to understanding not only the complex historical structure 
of science but also the equally complex structure of scientific knowledge, its levels, and types in our time.