A law, say, prohibits homosexual conduct or punishes the prostitute for plying her trade. According to some it is a bad law, according to others a necessary one. Those who argue that it is a bad law do so on a variety of grounds—that it is sheer folly to try to change human nature by law, that such legislation can only be effective at the price of the right to privacy, that the punishment of acts arising from compelling desires is cruel and excessive, that the law has no business meddling in what people do to others with their consent. Those who argue that it is a necessary law do so on one ground, that the act in question is immoral, and that what is wrong must be punished, lest the law itself fall into disrepute by failing to carry out a consistent campaign against wrong-doing.