Born: 480 BC in (possibly) Athens, Greece
Died: 411 BC in Athens, Greece
Antiphon was an orator and statesman who took up rhetoric as a profession. He was a Sophist and a contemporary of Socrates. These definite assertions are, however, disputed by some historians. The problem seems to revolve round whether there was one Sophist philosopher named Antiphon who lived around this time or whether there are two, or as some experts claim, three distinct Antiphons.
In what follows we shall assume that at least the orator named Antiphon was the same person as the Sophist who made the mathematical advances. This is the same line as taken in  while in  only Antiphon as an orator is discussed without reference to the philosophical or mathematical works. In  the hypothesis that Antiphon is one, or several different men is discussed without any definite view being preferred either way.
A number of speeches which were written by Antiphon have been preserved. Three of these speeches were real speeches made by Antiphon as the prosecutor in murder trials. Twelve speeches are specimen speeches written by Antiphon for use in teaching students the skills of prosecuting and defending clients in cases. The speeches come as three collections of four; two prosecution speeches and two defence speeches for each of three different cases.
Antiphon published a number of works on philosophy which have been lost except for a small number of fragments which have been discovered together with some quotations from the works in the writings of other authors. These works include On Truth, On Concord, The Statesman, and On Interpretation of Dreams. The work On Truth is written to support the views of Parmenides who believed that there was a single sole reality and that the apparent world of many things was unreal. In this work Antiphon is defending the same philosophical ideas which Zeno of Elea supported with his paradoxes.
In On Concord Antiphon :-
... defends the authority of the community as a safeguard against anarchy and recommends the ideals of concord and self-restraint both within communities and within the individual soul. Most probably he was only concerned to criticise the laws of a city by asking whether or not they satisfy the "natural" needs of the individual.
Hobbs in  notes that:-
... some have doubted whether the same man could have written "On Truth" and the conventional gnomic utterances of "On Concord".
In  three reasons are given to support at least the same author for these two philosophical works:-
(1) "On Truth" is not as radical as it appears, but simply a plea for legal reform;
(2) its doctrines, although radical, are not endorsed by Antiphon;
(3) Antiphon changed his mind.