Everywhere except in the field of jurisprudence, the reductio ad absurdum is accepted as a logical argument. The reductio always takes this form: If you can show that a certain premise leads to an absurd conclusion, then there is something radically wrong with the premise, and you then either have to reject the premise or at least amend it so that it no longer produces an absurd conclusion.
For instance, every semester I teach a college course in Ethics (or Moral Philosophy), and along the way I tell my students about the theory of ethical hedonism, according to which pleasure is the only good, pain the only evil. Other things — wealth or poverty, for example — might be good or evil in an instrumental way (that is, insofar as they lead to pleasure or pain), but only pleasure is good in itself, and only pain is bad in itself. I ask my students if they agree with the hedonistic theory. A few hands go up, indicating agreement. And who can be surprised? After all, wouldn’t we all like a life filled with enjoyment, devoid of pain?
Having explained the theory, I then refute it by means of a reductio ad absurdum. I offer my students something called a “happiness pill.” It is a new scientific development, I tell them, guaranteeing a lifetime of uninterrupted pleasure without even the slightest bit of pain. It’s a tiny pill that’s easy to take: You only have to take a single pill, and you only have to take it once — no repeated administrations are ever needed. It is free of charge (the manufacturer happens to be a friend of mine, and he has given me a few dozen samples). The happiness pill does not shorten your life: Given moderate amounts of nutrition, hydration, and sleep, you’ll live to be at least 100 years old.
Now, if you truly believe in hedonism, you should take the pill, since it gives you, better than anything else that has ever been devised or thought of, a life of pure pleasure and no pain. I invite my students to take the pill. Most of them hesitate, even the ones who earlier indicated that they agree with the hedonistic theory. “Why do you hesitate?” I ask. They ask me a few questions, which I answer as best I can, and as I do it emerges that this marvelous pill has a few drawbacks (though none that should deter a true hedonist).
Having taken the pill, you will feel such complete contentment that you will feel no desire to get out of bed in the morning; you will lie pleasantly in bed for the rest of your long life. And of course you’ll have no desire to eat or drink, and no desire to get up and take a bath or shower. “No problem,” I assure the students. “We’ll provide you with round-the-clock nursing care. Your nutrition and hydration will be provided to you intravenously. The nurses will roll you over from time to time so that you don’t develop bedsores; and needless to say the nurses will bathe you every day. Your muscles will deteriorate, of course. But so what? You’ll have no need for muscles. You will have no friends, no sports, no sex life, no love affairs, no spouse, no children or grandchildren, no job, no TV or movies, no books, no Internet, no mobile phone, no travel, no college degree, and so on.
“In the old days — the days prior to the happiness pill — these things often gave pleasure (always mixed, however, with a certain amount of pain). But who needs them now — now that we have an infallible device for delivering pleasure and preventing all pain?”
In the end, none of the students wants the pill. They now realize that, while they consider pleasure to be a good thing and pain a bad thing, they don’t consider pleasure to be the only good thing or pain the only bad thing. They want a pleasant life, yes, but also a life of family, friends, career, and so on — even if this life of family, friends, and career is notably less pleasant than a life of pill-induced, totally inactive, bed-ridden delight.
I then announce that I have refuted the theory of hedonism by means of a reductio. If the hedonistic premise leads to the conclusion that we should ingest the happiness pill, then there must be something wrong with this premise; hedonism must a false theory.
Return now to our judicial theorists. Nearly a half-century ago, they determined that “privacy” is a fundamental right guaranteed by the United States Constitution. Of course, no right of privacy is literally mentioned in the Constitution, but no matter: You can find it in the document’s “penumbra” if you wear the right kind of juridical reading glasses. And so in the Griswold v. Connecticut decision (1965), the Supreme Court discovered that, because of this right of privacy, married couples have a constitutional right to practice contraception. A few years later (in the 1973 Roe v. Wade decision), this led to a new discovery, namely the constitutional right to kill unborn babies. By the early 21st century (in the Lawrence v. Texas ruling), the Court had discovered a constitutional right to sodomy. In the future, the Court will probably discover a right to same-sex marriage, and after that (who can doubt it?) a right to polygamy.
Now, the normal human mind, seeing that the right to privacy leads to the absurd conclusion that the U.S. Constitution is an instrument made to protect abortion, sodomy, same-sex marriage, polygamy, and God knows what else, would pause and say: “Maybe we made a mistake with our initial premise of privacy.” But not the judicial mind. It says instead: “If a certain constitutional theory leads to absurdity, then we must conclude that absurdity is what James Madison and the Framers of the Constitution intended. Long live absurdity!”