The tutor turned his little eyes doubtfully upon the tennis boys, but
answered, reciting the language of his notes: "The idealistic theory
does not apply to the thinking ego, but to the world of external
phenomena. The world exists in our conception of it.

"Then," said the second boy, "when a thing is inconceivable?"

"It has no existence," replied the tutor, complacently.

"But a billion dollars is inconceivable," retorted the boy. "No mind
can take in a sum of that size; but it exists."

"Put that down! put that down!" shrieked the other boy. "You've struck
something. If we get Berkeley on the paper, I'll run that in." He
wrote rapidly, and then took a turn around the room, frowning as he
walked. "The actuality of a thing," said he, summing his clever
thoughts up, "is not disproved by its being inconceivable. Ideas alone
depend upon thought for their existence. There! Anybody can get off
stuff like that by the yard." He picked up a cork and a foot-rule,
tossed the cork, and sent it flying out of the window with the
foot-rule.

"Skip Berkeley," said the other boy.

"How much more is there?"

"Necessary and accidental truths," answered the tutor, reading the
subjects from his notes. "Hume and the causal law. The duality, or
multiplicity, of the ego."