The article analyzes how evidentiary reasoning works and what is its incidence in the accreditation of facts. The existing links between the evidential statements and the propositional attitudes of judge are explained. From there, the evidentiary issue in relation to psychological facts is analyzed in a particularized manner, reviewing the different postulates that have led the doctrine to argue that we are not dealing with facts susceptible of being proved. Finally, it is explained that, in spite of the diculties, there is no impediment to sustain that psychological facts can be proved.