Full Idea
Cause and effect is not a truth but rather a hypothesis - and indeed the one which we use to anthropomorphise the world for ourselves, bringing it in closer proximity to our feelings ('willing' is projected into it).
Gist of Idea
Cause and effect is a hypothesis, based on our supposed willing of actions
Source
Friedrich Nietzsche (Unpublished Notebooks 1884-85 [1884], 25[371])
Book Reference
Nietzsche,Friedrich: 'Fragments from 1884-85 (v 15)', ed/tr. Loeb,P.S./Tinsley,D.F. [Stanford 2022], p.96
A Reaction
That is (I think), we read the gap between thought and action onto natural external events, dividing them up. We treat the flow of events as if they were agent causation. Modern theories seem close to Nietzsche's unified view.