Seeing a red apple is technically evidence that all ravens are black

'All ravens are black' logically means the same thing as 'everything that isn't black isn't a raven.' So spotting a red apple — a non-black non-raven — counts as a tiny piece of confirming evidence for the raven claim, by the same logic used to confirm it with an actual black raven. Carl Hempel used the paradox to expose a flaw in naive theories of how evidence confirms scientific claims.

— Carl Gustav Hempel, Studies in the Logic of Confirmation — Mind, 1945