Cynicism and skepticism are nowadays conceived as curiosities in the history of philosophical thought, reduced to "eccentric" characters like Diogenes of Sinope and Pyrrho of Elis and a series of anecdotes about them.However, they have gone beyond classical antiquity to the present. Both schools of thought offer a constant challenge to the "official" thought bon ton: mocking and irreverent criticism in the case of the first and extreme relativismin the second.This paper presents an epistemological approach supporting the recovery of the cynicism and the pyrrhonian skepticism principles for the criticism of the historical thought in the modernity It is divided into two parts: the first one shows the broad features of these philosophical trends and the second examines their contributions to historical knowledge based on two cases: Cioran for the cynicism and Veyne for the skepticism.