The opposition between a rational and an irrational behavior or thought poses difficulties in understanding: what do we really mean by «irrational»? A behavior or a thought that adheres to emotions and does not arise from slow reflection can be considered irrational; on the other hand, can we state that emotional reactions and intuitions are «irrational»? I draw from Aristotle’s De Anima the idea of bringing emotions, sensations and intellect back to a unitary movement and placing them in a certain (...) distinction with respect to dianoetic reason; Aristotelian’s bestowal of cognitive value on emotions was then lost, in Western gnoseology, in parallel with the devaluation of the prerogatives of the intellect. An analysis of the psychological literature on emotions and a summary of the history of the relationship between intellect and reason allows us to propose a new point of view on these issues. (shrink)