Full Idea
Motivation is causality seen from within.
Gist of Idea
Motivation is causality seen from within
Source
Arthur Schopenhauer (Fourfold Root of Princ of Sufficient Reason [1813], p.214), quoted by Christopher Janaway - Schopenhauer 2 'Fourfold'
Book Reference
Janaway,Christopher: 'Schopenhauer' [OUP 2002], p.26
A Reaction
This is more illuminating about causation than about motivation, since we can be motivated without actually doing anything.