The Stoics offer us a very puzzling conception of causation and an equally puzzling ontology. The aim of the present paper is to show that these two elements of their system elucidate each other. The Stoic conception of causation, I contend, holds the key to understanding the ontological category of incorporeals and thus Stoic ontology as a whole, and it can in turn only be understood in the light of this connection to ontology. The thesis I defend is that the (...) Stoic incorporeals are to be understood as effects, as effects of the causality of bodies. What is gained by this thesis? First, it explains how the seemingly heterogeneous item of ‘sayables’ (lekta) fits into the category of incorporeals. Second, it allows for a new interpretation of the two verbs with which the Stoics characterize the way of being of incorporeals, huphistanai and huparchein. And, third, it sheds light on the peculiar features of the Stoic conception of causation. (shrink)