Arcesilaus redirected the Academy toward skeptical dialectic, arguing against Stoic confidence that a cognitive impression could furnish a secure criterion of truth.
Intellectual setting
His headship marked the transition to the so-called New Academy amid intense Hellenistic disputes about knowledge and action.
Key ideas
Suspension of assent
When arguments are balanced, withholding assent protects inquiry from claiming more than the evidence allows.
Dialectical practice
Arcesilaus used opponents' claims, especially Stoic ones, to test whether any proposed criterion is immune to error.
Legacy
Arcesilaus established a form of Academic skepticism that shaped Carneades, Cicero, and modern readings of Platonic inquiry.