Full Idea
Every account is either a definition or a demonstration.
Gist of Idea
An account is either a definition or a demonstration
Source
Aristotle (De Anima [c.329 BCE], 407a24)
A Reaction
That is, it is either a summary of the thing's essential nature, or it is a proof of some natural fact, starting from first principles.
Book Reference
Aristotle: 'De Anima (on the psuche)', ed/tr. Reeve, C.D.C. [Hackett 2017], p.11
Related Idea
Idea 24048 Demonstrations move from starting-points to deduced conclusions [Aristotle]