'And when some one boasts of a catalogue of twenty-five
ancestors, and goes back to Heracles, the son of
Amphitryon, he cannot understand his poverty of ideas. Why
is he unable to calculate that Amphitryon had a
twenty-fifth ancestor, who might have been anybody, and was
such as fortune made him, and he had a fiftieth, and so on?
He is amused at the notion that he cannot do a sum, and
thinks that a little arithmetic would have got rid of his
senseless vanity.'