Why did Academic skeptics argue that certainty was impossible?

Academic skeptics, associated with the Academy founded by Plato, argued that certainty was impossible because they believed no reliable criterion exists to distinguish truth from falsehood.12

Leaders of this school, such as Arcesilaus and Carneades, challenged the dogmatic claims of schools like Stoicism and Epicureanism by asserting that human knowledge is limited to probability rather than absolute certainty. They maintained that since there is no definitive standard for truth, one should withhold assent from any experience that claims to be certain knowledge.123

This position, often referred to as acatalepsy, was rooted in the belief that neither the senses nor the intellect can provide conclusive evidence of reality. Consequently, Academic skeptics advocated for a probabilistic approach, suggesting that while we cannot attain absolute truth, we can establish reasonable or probable standards to guide our judgments.231