Encyclopedia of Philosophy: Aenesidemus (1st century BC)

 Aenesidemus was a Greek philosopher of the first century BC who revived Pyrrhonian Scepticism, formulating the basic Ten Modes of Scepticism, or tropoi, and demonstrating that concepts such as cause, explanation, goodness and the goal of life engendered endemic and undecidable dispute; faced with this the Sceptic suspends judgment - and tranquillity follows. Aenesidemus was probably active around the middle of the first century BC. He considered that Academic scepticism under Philo of Larissa had so far abandoned its original, uncompromising attitude to knowledge that he described the dispute between Philo and Antiochus as ‘Stoics fighting with Stoics’ (fr. 71C9).