Page:The art of controversy and other posthumous papers (IA artofcontroversy00schouoft).pdf/46

 indeed, long before it had been reached, namely, at 212° Fahrenheit—the sea would have been boiled away, and spread through the air in the form of steam. At this the audience laughs. To refute the objection, your opponent would have to show that the boiling-point depends not only on the degree of warmth, but also on the atmospheric pressure; and that as soon as about half the sea-water had gone off in the shape of steam, this pressure would be so greatly increased that the rest of it would fail to boil even at a temperature of 480°. He is debarred from giving this explanation, as it would require a treatise to demonstrate the matter to those who had no acquaintance with physics.

If you find that you are being worsted, you can make a diversion—that is, you can suddenly begin to talk of something else, as though it had a bearing on the matter in dispute, and afforded an argument against your opponent. This may be done without presumption if the diversion has, in fact, some general bearing on the matter; but it is a piece of impudence if it has nothing to do with the case, and is only brought in by way of attacking your opponent. For example, I praised the system prevailing in China, where there is no such thing as hereditary nobility, and offices are bestowed only on those who succeed in competitive examinations. My opponent maintained that learning, as little as the