Organon §98

Give the most credence to the patient's own words, but also investigate the case with circumspection, scrupulousness, knowledge of human nature, cautious inquiry and patience.

It is certain that, on hearing about a patient's ailments and sensibilities, one has to ascribe belief principally to the patient himself, especially to his own expressions with which he can render an account of his sufferings. (These are wont to be altered and falsified in the mouths of relations and attendants.) However, it is just as certain that the investigation of the true complete image of the disease and its details requires (with all diseases, but principally with the protracted ones) special circumspection, scrupulousness, knowledge of human nature, cautious inquiry and patience-all to a high degree.