Arcesilaus

Arcesilaus (c. 316–241 BCE) became head of the Academy and turned Plato’s school toward a radical scepticism, holding that nothing can be known with certainty and that the wise course is to suspend judgement (epochē).

Reviving the questioning manner of Socrates, he argued on both sides of every question and asserted no doctrine of his own, opposing above all the confident dogmatism of the Stoics. With him begins the long sceptical phase of the Academy carried on by Carneades.