The only way that has ever been discovered to have a lot of people cooperate together voluntarily is through the free market. And that’s why it’s so … - Milton Friedman

A largely parallel example involving human behavior has been used elsewhere by Savage and me. Consider the problem of predicting the shots made by an expert billiard player. It seems not at all unreasonable that excellent predictions would be yielded by the hypothesis that the billiard player made his shots as if he knew the complicated mathematical formulas that would give the optimum directions of travel, could estimate accurately by eye the angles, etc., describing the location of the balls, could make lightning calculations from the formulas, and could then make the balls travel in the direction indicated by the formulas. Our confidence in this hypothesis is not based on the belief that billiard players, even expert ones, can or do go through the process described; it derives rather from the belief that, unless in some way or other they were capable of reaching essentially the same result, they would not in fact be expert billiard players.
It is only a short step from these examples to the economic hypothesis that under a wide range of circumstances individual firms behave as if they were seeking rationally to maximize their expected returns (generally if misleadingly called "profits") and had full knowledge of the data needed to succeed in this attempt; as if, that is, they knew the relevant cost and demand functions, calculated marginal cost and marginal revenue from all actions open to them, and pushed each line of action to the point at which the relevant marginal cost and marginal revenue were equal. Now, of course, businessmen do not actually and literally solve the system of simultaneous equations in terms of which the mathematical economist finds it convenient to express this hypothesis, any more than leaves or billiard players explicitly go through complicated mathematical calculations or falling bodies decide to create a vacuum. The billiard player, if asked how he decides where to hit the ball, may say that he "just figures it out" but then also rubs a rabbit's foot just to make sure; and the businessman may well say that he prices at average cost, with of course some minor deviations when the market makes it necessary. The one statement is about as helpful as the other, and neither is a relevant test of the associated hypothesis.

The great enemy of human freedom is the Government. By taking money out of our pockets and spending it, it destroys our freedom.

"(7) The impact on public schools. It is essential to separate the rhetoric of the school bureaucracy from the real problems that would be raised. The National Education Association and the American Federation of Teachers claim that vouchers would destroy the public school system, which, according to them, has been the foundation and cornerstone of our democracy. Their claims are never accompanied by any evidence that the public school system today achieves the results claimed for it — whatever may have been true in earlier times. Nor do the spokesmen for these organizations ever explain why, if the public school system is doing such a splendid job, it needs to fear competition from nongovernmental, competitive schools or, if it isn't, why anyone should object to its "destruction." The threat to public schools arises from their defects, not their accomplishments. In small, closely knit communities where public schools, particularly elementary schools, are now reasonably satisfactory, not even the most comprehensive voucher plan would have much effect. The public schools would remain dominant, perhaps somewhat improved by the threat of potential competition. But elsewhere, and particularly in the urban slums where the public schools are doing such a poor job, most parents would undoubtedly try to send their children to nonpublic schools."