Arcesilao

Arcesilao, also spelled Arcesilaus (Greek: Arkésilāos), is the Latinized name commonly used for the Greek philosopher known as the head of the Platonic Academy in Athens during the mid-to-late 3rd century BCE. He is traditionally dated to have led the Academy from roughly 262/1 BCE until his death in the 240s BCE. Details of his early life are scarce, and most of what is known about him comes from later biographers and ancient sources.

Arcesilao is best known for ushering a more skeptical orientation into the Academy, a development later termed Academic Skepticism. He is believed to have argued that certainty in knowledge is unattainable and that philosophical positions should be held with caution. Rather than presenting doctrinal teachings, he emphasized dialectical questioning and the examination of opposing views, aiming to prevent rash assent and to demonstrate the limits of justification.

No authentic writings of Arcesilao survive. Our understanding of his doctrines comes mainly from later skeptical writers and biographers, including Diogenes Laertius and Cicero, who summarize the shift in the Academy under his leadership. His influence is recognized in the way the Academy moved away from fixed dogmas toward a practice of skeptical inquiry, which was carried forward by his successors, notably Carneades.

Arcesilao’s legacy lies in shaping the trajectory of Hellenistic philosophy toward systematic doubt and critical examination. He is viewed as a transitional figure between the Old Academy’s doctrinal debates and the later skeptical tradition that characterized much of ancient Greek philosophy.