Via Boing Boing, where Maggie Koerth-Baker gave a delightful pointer to this film of Feynman explaining for seven-and-a-half minutes why he can’t really explain why magnets repel each other. Or attract, either.
And trumping him in time and space, Bierce gave us this in 1906:
Something acted upon by magnetism.
Something acting upon a magnet.
The two definitions immediately foregoing are condensed from the works of one thousand eminent scientists, who have illuminated the subject with a great white light, to the inexpressible advancement of human knowledge.