“Logic, my boy,” said Dr. Boyle patiently, between his teeth. “It doesn’t make sense. You could go back in time, kill a man, and wipe out God-knows-how-many descendants. Knock off Charlemagne, and you kill about every white man on earth. Ridiculous! Why don’t you go into gunrunning, and sell the ancient Athenians a couple of machine guns so they can win the Peloponnesian War? Why not go back and invent the lightbulb, the telephone, and the airplane before Edison, Bell, and the Wrights get around to it? Think of the royalties!”
