Fastest thing on earth

Four Irish philosophers were discussing what was the fastest thing on earth.

No 1 said a thought was the fastest thing - "when I think something I forget it before I have time to remember it."

No 2 said a blink. "I can blink and before I know my eyes are shut they're open again."

No 3 said an electric light. "When I turn on the light its on before I can turn my head to look at it."

No 4 said "dysentry" "I woke up last night and before I could Think, Blink or turn on the light, I'd s**t myself"