Famous German philosopher (1724-1804).
MontyPython says, in the first line of the Philosophers Song (from the "Bruces Sketch"):
''ImmanuelKant was a real pissant who was very rarely stable..."
A highly misunderstood famous German philosopher who strikes terror into the hearts of undergraduates everywhere. And those are just ones who only have to read TheGroundingOfTheMetaphysicsOfMorals?, not TheCritiqueOfPureReason.
(I got 67% in Kant without reading the texts)
Perhaps that's an indicator of just how much mindshare his philosophy occupies in modern Western thought - you're familiar with his work without even realizing it. -- MikeSmith
Kant was also the first person to publish the hypothesis that the "nebulae" were "island universes" like our own milky way -- in effect, he was the first person to figure out that they were galaxies.
See also KantsCategoricalImperative