Ἄδηλον. Unclear, non-evident. (Privative a plus dēlon, clear). Anaxagoras says, “Phenomena are a glimpse of the adēla” (B21). For the Epicureans, adēla are those things that exist but cannot be directly perceived, only demonstrated on the basis of observation—for example, the void. Academic Skeptics were accused of making everything non-evident. (HDAGP)