Nous is most likely derived from the root snu, meaning "to sniff." Homer uses nous to mark the realization or understanding of a situation or state of affairs. Nous penetrates beyond the surface features of a situation and reveals the underlying truth of the matter. It is not divorced from perception and its most primitive function is that of apprehending or "smelling" danger. In Homer nous is also linked to the visualization of a plan of action that is immediately prompted by the awareness of a situation possessing emotional impact.

In Parmenides nous maintains its Homeric function as that which reveals ultimate truth. However, it also serves as the source of logical reasoning. In Parmenides nous is divorced from perception and it is best understood to mean "thought" or "intellect." In accordance with his rather austere ontology, Parmenides may well hold that that which exists is also that...