Full Idea
Fancy being unable to distinguish between the cause of a thing, and the condition without which it could not be a cause.
Gist of Idea
Fancy being unable to distinguish a cause from its necessary background conditions!
Source
Plato (Phaedo [c.374 BCE], 099c)
Book Reference
Plato: 'The Last Days of Socrates', ed/tr. Tredennick,Hugh [Penguin 1969], p.157
A Reaction
Not as simple as he thinks. It seems fairly easy to construct a case where the immediately impacting event remains constant, and the background condition is changed. Even worse when negligence is held to be the cause.