SEXTUS EMPIRICUS, physician and philosopher, wrote in the latter part of the third century CE. Little is known of Sextus's life. He seems to have resided for a while in Rome and later in Alexandria.
Though his medical writings are lost, Sextus's surviving philosophical works are Outlines of Pyrrhonism, Against the Dogmatists, Against the Logicians, Against the Physicists, Against the Ethicists, and Against the Professors. Also ascribed to him are a treatise On the Soul and Notes on Medicine.
Sextus represented the new skeptical school founded by Aenesidemus of Cnossos, whose system Sextus endeavored to clarify. Briefly, the skeptics devoted themselves to critiquing and pointing out the shortcomings of every positive philosophical doctrine. Sextus himself was a major proponent of the Pyrrhonistic "suspension of judgment" (named for the philosopher Pyrrho of Elis [ca. 360-270 BCE), which maintained that we can obtain no undeniably true knowledge of reality. This being the case, we should refrain from forming judgments about things we cannot truly understand.
While Sextus's writings may appear wanting in originality, they are a valuable compilation of the work of his predecessors, and for this very reason, they provide us with a much-needed description of ancient skepticism.