>>>>>"I think, therefore I am" said {insert your favorite stupid ethnic group} and vanished.
>>>>
>>>>The variant I've heard is:
>>>>
>>>>Descartes walked into a bar. The bartender asked is he wanted something to drink. Descartes replied "I think not" and ceased to exist.
>>>>
>>>
>>>Was Descartes in the bar before or after the horse?
>>
>>Probably after. Wouldn't be a good idea to have Descartes before the horse.
>
>Um, I think that pun was already understood :-)

Actually, I think the horse in question didn't have to do anything with the cart (it's a bar, not a grocery!). He just came in, and the bartender asked "why the long face, pal?"