Abstract
The starting point of considerations developed in this paper is done by the intersection between Descartes' rationalist idea of the human mind and Hume's skeptical thought on the possibility of inferring 'ought' from 'is'. The first part focuses on the normativist responses to the problem of the rationality and critical reactions to them expressed by representatives of the psychological and cognitivist studies of reasoning (J.
Evans, S. Elqayam, K.
Stanovich, D. Over, M.
Oaksford, N. Chater, et al.).
The second part treats the topic of the deontic reasoning and the consequences of the theory of deontic introduction (Elqayam, Evans) for the philosophical idea of the rationality.