<P> Socrates, born in Athens in the 5th century BCE, marks a watershed in ancient Greek philosophy . Athens was a center of learning, with sophists and philosophers traveling from across Greece to teach rhetoric, astronomy, cosmology, geometry, and the like . The great statesman Pericles was closely associated with this new learning and a friend of Anaxagoras, however, and his political opponents struck at him by taking advantage of a conservative reaction against the philosophers; it became a crime to investigate the things above the heavens or below the earth, subjects considered impious . Anaxagoras is said to have been charged and to have fled into exile when Socrates was about twenty years of age . There is a story that Protagoras, too, was forced to flee and that the Athenians burned his books . Socrates, however, is the only subject recorded as charged under this law, convicted, and sentenced to death in 399 BCE (see Trial of Socrates). In the version of his defense speech presented by Plato, he claims that it is the envy he arouses on account of his being a philosopher that will convict him . </P> <P> While philosophy was an established pursuit prior to Socrates, Cicero credits him as "the first who brought philosophy down from the heavens, placed it in cities, introduced it into families, and obliged it to examine into life and morals, and good and evil ." By this account he would be considered the founder of political philosophy . The reasons for this turn toward political and ethical subjects remain the object of much study . </P> <P> The fact that many conversations involving Socrates (as recounted by Plato and Xenophon) end without having reached a firm conclusion, or aporetically, has stimulated debate over the meaning of the Socratic method . Socrates is said to have pursued this probing question - and - answer style of examination on a number of topics, usually attempting to arrive at a defensible and attractive definition of a virtue . </P> <P> While Socrates' recorded conversations rarely provide a definite answer to the question under examination, several maxims or paradoxes for which he has become known recur . Socrates taught that no one desires what is bad, and so if anyone does something that truly is bad, it must be unwillingly or out of ignorance; consequently, all virtue is knowledge . He frequently remarks on his own ignorance (claiming that he does not know what courage is, for example). Plato presents him as distinguishing himself from the common run of mankind by the fact that, while they know nothing noble and good, they do not know that they do not know, whereas Socrates knows and acknowledges that he knows nothing noble and good . </P>

When did some greek philosophers start to question the reliability of poetic accounts of the past