The focus of this paper is the dispute between the Academic Arcesilaus of Pitane (ca. 316–214 BC) and the early Stoic philosophy of Zeno of Citium. Scholars typically claim that Arcesilaus set out to attack Zeno's epistemology, or theory of knowledge. The framework of epistemology prevails in the modern reconstruction of Arcesilaus's arguments. Proponents of this framework usually contend that the epistemic possibility of Stoic κατάληψσις is the principal aim of Arcesilaus's attack. The aim of this article is to contest the limited scope of the framework of epistemology in the interpretation of Arcesilaus's attack, and reposition his critical arguments, in view of the fragmentary evidence, within the framework of an ontology of knowledge. The paper reconstructs Academic indiscernibility arguments against the early Stoa to show that the attack on the epistemic possibility of κατάληψσις sets out to undermine the ontological conditions of Stoic κατάληψσις.