This paper provides a comprehensive study of the Epicurean theory of ‘preconception’. It addresses what a preconception is; how our preconception of the gods can be called innata, innate; the role played by epibolai ; and how preconceptions play a semantic role different from that of ‘sayables’ in Stoicism. The paper highlights the conceptual connections between these issues, and also shows how later Epicureans develop Epicurus’ doctrine of preconceptions while remaining orthodox about the core of that doctrine.