In previous eras you would inadvertently get exercise by doing almost anything—running after buffalo, harvesting rice, gathering firewood, avoiding hostile neighbors. Today we have built a culture in which exercise is nonessential and even inconvenient. You seldom have to lift or carry anything of any weight, you need never walk more than a city block, and elevators (essentiallyforklifts for humans) can take you to any floor of any building you enter.Today, people who want to be more fit often find that they have to drive to a business specially devoted to that purpose, change their clothes, get on special exercise machines that accomplish nothing other than help the inert burn energy, change their clothes again, and drive home. Some gyms have escalators, so you needn’t exhaust yourself climbing any stairs before you arrive at the StairMaster.Of course, anyone who watches late-night television will know that gyms are not essential; one can simply purchase cheaply built home exercise equipment. This is easily avoided, but if you one day awaken and discover with alarm that you or a well-meaning friend has ordered such a device, all is not lost. Just do what almost everyone else does. Hang a piece of clothing on it. Henceforth it is unlikely to be used for anything else.