Plato, the great philosopher of Athens, was born in 427 BCE. In early manhood an admirer of Socrates, he later founded the famous school of philosophy in the grove Academus. Much else recorded of his life is uncertain; that he left Athens for a time after Socrates' execution is probable; that later he went to Cyrene, Egypt, and Sicily is possible; that he was wealthy is likely; that he was critical of 'advanced' democracy is obvious. He lived to be 80 years old. Linguistic tests including those of computer science still try to establish the order of his extant philosophical dialogues, written...

Plato, the great philosopher of Athens, was born in 427 BCE. In early manhood an admirer of Socrates, he later founded the famous school of philosophy in the grove Academus. Much else recorded of his life is uncertain; that he left Athens for a time after Socrates' execution is probable; that later he went to Cyrene, Egypt, and Sicily is possible; that he was wealthy is likely; that he was critical of 'advanced' democracy is obvious. He lived to be 80 years old. Linguistic tests including those of computer science still try to establish the order of his extant philosophical dialogues, written...

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...