post by Bill Gardner
Could you define the market — everybody has to buy food sooner or later, so you define the market as food, therefore, everybody is in the market; therefore, you can make people buy broccoli...
The basic strategy of argument is "if you move a step in direction X, you will inevitably end at location X*, which is horrible." Why stepping toward X leads you to X* is unexplained, so the argument seems to have only rhetorical force.
But there is at least one slippery slope argument which sometimes makes better sense. You can be in a situation where circumstances press you to step in direction X. But the situation has positive feedback, so that moving a step toward X generates consequences that increase the pressure for further movement. The natural and social worlds are full of examples of positive feedback, such as fission warheads, avalanches, cattle stampedes, and bank runs.
The classical example of a slippery slope in politics, as it were, is Pericles' speech to the Athenian Ecclesia urging war with Sparta over a seemingly peripheral issue. It begins, "Athenians, I say, as I always have said, that we must never yield to the Peloponnesians."
For some time past the designs of the Lacedaemonians have been clear enough, and they are still clearer now. Our agreement says that when differences arise, the two parties shall refer them to arbitration, and in the mean time both are to retain what they have. But for arbitration they never ask; and when it is offered by us, they refuse it. They want to redress their grievances by arms and not by argument; and now they come to us, using the language, no longer of expostulation, but of command. They tell us to... rescind the decree respecting the Megarians... I would have none of you imagine that he will be fighting for a small matter if we refuse to annul the Megarian decree, of which they make so much, telling us that its revocation would prevent the war. You should have no lingering uneasiness about this; you are not really going to war for a trifle. For in the seeming trifle is involved the trial and confirmation of your whole purpose. If you yield to them in a small matter, they will think that you are afraid, and will immediately dictate some more oppressive condition.
In other words, the attempt to appease the Spartans will not only cause us harm, but will also embolden them to demand even more.
Now, does positive feedback apply to the constitutionality of health care reform? I don't think so. Scalia may believe that if the government can mandate the purchase of health insurance, it will be emboldened, like the Spartans, to demand further control over economic life. But if there was positive feedback here, wouldn't we expect that the many societies that implemented nationalized health care systems after World War 2 would have accelerated towards totalitarianism? In fact, after a rapid expansion of governmental control of the economy, there was a world wide reversal in the 80s and 90s. So the idea that there is positive feedback loop driving the expansion of social democracy doesn't seem to fit the evidence, but the idea itself is not empty.