Academic Skepticism

Academic Skepticism is the skeptical phase of Plato's Academy that dominated the school from the mid-third century BCE, beginning under the scholarch Arcesilaus and reaching its most systematic form under Carneades, who argued that certain knowledge (in the Stoic sense of an infallible, self-evidently true impression) is unattainable and that the wise course is to suspend judgment (epoche) on all matters rather than assent to any claim as certain. Unlike Pyrrhonism, which suspended judgment on nearly everything including the value of suspension itself, Academic Skeptics such as Carneades held that although certainty is impossible, some impressions are more "convincing" or probable than others, and that a rational person can and should act on the balance of probability without ever claiming to know. The school developed its skeptical arguments largely as a running polemical challenge to Stoic epistemology's claim that certain "cognitive impressions" guarantee truth, and Carneades became famous for arguing both sides of major philosophical questions with equal skill to demonstrate that certainty was unattainable on either side. The skeptical phase of the Academy ended under Antiochus of Ascalon in the early first century BCE, who rejected skepticism in favor of a return to dogmatic Platonism, but Academic Skepticism's arguments survive today chiefly through Cicero's philosophical works, which remain the fullest surviving record of the school's positions.