Throughout history philosophers have sought to define, understand, and delineate concepts important to human well-being. One such concept is "knowledge." Many philosophers believed that absolute, certain knowledge, is possible--that the physical world and ideas formulated about it could be given solid foundation unaffected by the varieties of mere opinion.

Sextus Empiricus stands as an example of the "skeptic" school of thought whose members believed that knowledge was either unattainable or, if a genuine possibility, the conditions necessary to achieve it were next to impossible to...