We know the scientists reading this blog will find this joke funny….
A scientist has two large jars in front of him. One jar contains many fleas, the other jar is empty. He gently removes a flea from the flea jar, places it on the table before the empty jar, steps back, and commands “Jump,” whereupon the flea jumps into the empty jar. Methodically he gently removes each flea, places it on the table, says “Jump,” and the flea jumps into the originally empty jar.
When he has transferred all the fleas in this way, he removes one from the now full jar, carefully pulls off its back legs, and places it on the table before the original jar. He commands “Jump,” but the flea does not move. He takes another flea from the jar, carefully pulls off its back legs, and places it on the table. Again he commands “Jump,” but the flea does not move. Methodically, he goes through this same procedure with the remaining fleas, and gets the same results.
The scientist records in his notebook, “A flea, when its back legs are pulled off, cannot hear.”