"Denis Diderot Was A French Philosopher In The 18Th Century" joke
Denis Diderot was a French philosopher in the 18th century. He traveled Europe extensively, and on his travels also stopped at the Russian court in St. Petersburg. His wit and suave charm soon drew a large following among the younger nobles at the court - and so did his atheist philosophy. That worried empress Catherine the Great very much...
Swiss mathematician Leonhard Euler was working at the Russian court at that time, and unlike Diderot, he was a devout Christian. So, the empress asked him for help in dealing with the threat posed by Diderot.
Euler had himself introduced to Diderot as a man who had found a mathematical proof for the existence of God. With a stern face the mathematician confronted the philosopher: "Monsieur, (a+bn)/n = x holds! Hence, God exists. What is your answer to that?"
Quick-witted Diderot was speechless, was laughed at by his followers, and soon returned to France.
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