Why might not whole communities and public bodies be seized with fits of insanity, as well as individuals? Nothing but this principle, that they are liable to insanity, equally at least with private persons, can account for the major part of those transactions of which we read in history.
Bishop Joseph Butler
Friedman continues, but I shortened the quote to make it punchier. Essentially he says that, (1) given a large number of individuals irrationality will average out in the aggregate, (2) In most cases that an economist would be interested in (eg. investors, CEOs) the individuals have been selected to be good at the task they are performing, i.e. not irrational in that domain.
A writer on structuralism in the Times Literary Supplement has suggested that thoughts which are confused and tortuous by reason of their profundity are most appropriately expressed in prose that is deliberately unclear. What a preposterously silly idea! I am reminded of an air-raid warden in wartime Oxford who, when bright moonlight seemed to be defeating the spirit of the blackout, exhorted us to wear dark glasses. He, however, was being funny on purpose.
Peter Medawar
I think Mencken was using it in the sense of, "A peasant; a rustic; a farm servant.", (see also). It's an unusual usage.
Suppose we know someone's objective and also know that half the time that person correctly figures out how to achieve it and half the time he acts at random. Since there is generally only one right way of doing things (or perhaps a few) but very many wrong ways, the "rational" behavior can be predicted but the "irrational" behavior cannot. If we predict the person's behavior on the assumption that he is rational, we will be right half the time. If we assume he is irrational, we will almost never be right, since we still have to guess which irrational thing he will do. We are better off assuming he is rational and recognizing that we will sometimes be wrong. To put the argument more generally, the tendency to be rational is the consistent (and hence predictable) element in human behavior. The only alternative to assuming rationality (other than giving up and assuming that human behavior cannot be understood and predicted) would be a theory of irrational behavior - a theory that told us not only that someone would not always do the rational thing but also which particular irrational thing he would do. So far as I know, no satisfactory theory of that sort exists.
David Friedman, Price Theory, An Intermediate Text
The inferior man's reasons for hating knowledge are not hard to discern. He hates it because it is complex - because it puts an unbearable burden upon his meagre capacity to take in ideas. Thus his search is always for short cuts. All superstitions are short cuts. Their aim is to make the unintelligible simple, and even obvious. So on what seem to be higher levels. No man who has not had a long and arduous education can understand even the most elementary concepts of modern pathology. But even a hind at the plough can grasp the theory of chiropractic in two lessons. Hence the vast popularity of chiropractic among the submerged - and of osteopathy, Christian Science and other such quackeries with it. They are idiotic, but they are simple - and every man prefers what he can understand to what puzzles and dismays him. The popularity of fundamentalism among the inferior orders of men is explicable in exactly the same way. The cosmogenies that educated men toy with are all inordinately complex. To comprehend their veriest outlines requires an immense stock of knowledge, and a habit of thought. It would be be as vain to try to teach the peasants or to the city proletariat as it would be to try to teach them to streptococci. But the cosmogeny of Genesis is so simple that even a yokel can grasp it. It is set forth in a few phrases. It offers, to an ignorant man, the irresistible reasonableness of the nonsensical. So he accepts it with loud hosannas, and has one more excuse for hating his betters.
H. L. Mencken, Homo Neanderthalensis
The day we allow biochauvinism to overtake Less Wrong is the day I leave for good.
Thank you, I stand corrected.
Brother Ty's seventh law