In English, the term sophist is most often used pejoratively, for one who argues with devious abuses of logic. The Greek Sophistês took on a similar sense in the fifth century BCE., but its original meaning is simply expert or wise person. In the study of Greek philosophy, the sophists denote a group of teachers and intellectuals of the fifth and fourth century BCE (the term is also used for later practitioners of their profession; this soon comes to be interchangeable with rhetoric or public speaking, as in the so-called Second Sophistic movement of the second century CE).

The sophists are perennially ambiguous and controversial figures, and it has long been debated whether they should be deemed philosophers. Two central points seem clear: First, the sophists did not constitute a philosophical school with a shared set of metaphysical and ethical positions; second, a number of them did...