Don’t Upset Descartes

This is René Descartes’ most famous quotation:

Cogito ergo sum. (I think; therefore, I am.)

The following moldy oldie, known by almost everyone, is based on that quote:

René Descartes was sitting in a bar. When asked if he wanted another, he said, “I think not.” And he promptly disappeared.

Slightly less well known is the following quote by Saul Steinberg:

“I think, therefore Descartes is.”

I rather like the following limerick based on Descartes’ famous quote:

There was a young student named Fred;
When asked about Descartes, he said:
“It’s perfectly clear
That I’m not really here,
For I haven’t a thought in my head.”

Tee-hee.

For my money, though, the best René Descartes quote is the following:

Each problem that I solved became a rule which served afterwards to solve other problems.

That reminds me of another moldy oldie, which comes in many different varieties…

A mathematician had tired of academia, so he decided to join the fire department. During his training, the chief asked him, “If you were walking down an alley and came across a dumpster that was on fire, what would you do?”

“Why, I’d get a hose and douse it, of course!”

“Correct,” said the chief. “And what would you do if you were walking down an alley and came across a dumpster that was not on fire?”

“I suppose I’d light the dumpster on fire.”

“You’d do what?” screams the chief.

“I’d light it on fire,” says the mathematician, “thereby reducing it to a previously solved problem.”