ABSTRACT: Decision-theoretic approach and a nonlinguistic theory of norms are applied in the paper in an attempt to explain the nature of scientific rationality. It is considered as a normative system accepted by scientific community. When we say that a certain action is rational, we express a speaker’s acceptance of some norms concerning a definite action. Scientists can choose according to epistemic utility or other rules and values, which themselves have a variable nature. Rationality can be identified with a decision to accept a norm. This type of decision cannot be reduced only to its linguistic formulation; it is an act of evolvement of the normative regulation of human behavior. Norms are treated as decisions of a normative authority...