Sextus Empiricus lived in the late second, early third centuries AD. He was a physician and a philosopher, and the last of the followers of Pyrrho of Elis (fourth/third century BC), an early Greek sceptic. One of Sextus' works, Outlines of Pyrrhonism (or here) (Gr. Purroneioi Hupotuposeis), is most known for this formulation of the earlier sceptical arguments. Pyrrhonian sceptics do not deny knowledge altogether. Rather, they deny that there is any way we can know something to be true. That is to say, the problems are (as in the three most important of the Agrippan modes): a) infinite regress (i. e., that one's belief is justified by something else, which itself needs justified by something else, and so on ad infinitum), or b) circular reasoning (i. e., that one's belief is justified by something else, but that other thing receives its justification by the belief in question), or c) dogmatism (i. e., that one's belief is justified by simple assertion of its truth, but this is no justification). Further, and this will have bearing on our ethical discussion in a moment, there is the <a href="http://www.geocities.com/Athens/