Interest has revived in the works of Sextus Empiricus in recent times, especially, one may say, since the date of Herbart. There is much in the writings of Sextus that finds a parallel in the methods of modern philosophy. There is a common starting-point in the study of the power and limitations of human thought. There is a common desire to investigate the phenomena of sense-perception, and the genetic relations of man to the lower animals, and a common interest in the theory of human knowledge. While, however, some of the pages of Sextus' works would form a possible introduction to certain lines of modern philosophical thought, we cannot carry the analogy farther, for Pyrrhonism as a whole lacked the essential element of all philosophical progress, which is a belief in the possibility of finding and establishing the truth in the subjects investigated. Before beginning a critical study of the writings of Sextus Empiricus, and the light which they throw on the development of Greek Scepticism, it is necessary to make ourselves somewhat familiar with the environment in which he lived and wrote. We shall thus be able to comprehend more fully the standpoint from which he regarded philosophical questions. Let us accordingly attempt to give some details of his life, including his profession, the time when he lived, the place of his birth, the country in which he taught, and the general aim and character of his works. Here, however, we encounter great difficulties, for although we possess most of the writings of Sextus well preserved, the evidence which they provide on the points mentioned is very slight. He does not give us biographical details in regard to himself, nor does he refer to his contemporaries in a way to afford any exact knowledge of them. His name even furnishes us with a problem impossible of solution. He is called [Greek: Sextos ho empeirikos] by Diogenes Laertius[1]: [Greek: Herodotou de diekouse Sextos ho empeirikos hou kai ta deka ton skeptikon kai alla kallista' Sextou de diekouse Satorninos ho Kythenas, empeirikos kai autos]. Although in this passage Diogenes speaks of Sextus the second time without the surname, we cannot understand the meaning otherwise than that Diogenes considered Sextus a physician of the Empirical School. Other evidence also is not wanting that Sextus bore this surname. Fabricius, in his edition of the works of Sextus, quotes from the _Tabella de Sectis Medicorum_ of Lambecius the statement that Sextus was called Empiricus because of his position in medicine.[2] Pseudo-Galen also refers to him as one of the directors of the Empirical School, and calls him [Greek: Sextos ho empeirikos].[3] His name is often found in the manuscripts written with the surname, as for example at the end of _Logic II_.[4] In other places it is found written without the surname, as Fabricius testifies, where Sextus is mentioned as a Sceptic in connection with Pyrrho. [1] Diog. Laert. IX. 12, 116.