The Nous

The nous was carefully distinguished from sense perception, imagination, and reason, although these terms are closely inter-related. The term was apparently already singled out by earlier philosophers such as Parmenides, whose works are largely lost. In post-Aristotelian discussions, the exact boundaries between perception, understanding of perception, and reasoning have not always agreed with the definitions of Aristotle, even though his terminology remains influential. In the Aristotelian scheme, nous is the basic understanding or awareness that allows human beings to think rationally. For Aristotle, this was distinct from the processing of sensory perception, including the use of imagination and memory, which other animals can do.