"So many humbugs, dear reader, and so little time," the authors remark at one point. And as for all the efforts of world improvement, they have this to say: "[t]he negative consequences at the end of an effort at world improvement are roughly equal and opposite to the positive aspirations at the beginning." The problem is that otherwise reasonable, intelligent individuals, be they "[i]mperialists, anti-imperialists, capitalists, communists — as soon as they get a grand scheme into their heads, a pet project for world improvement, they all seem to end up in the same place — bungling, botching, and butchering." If you "put them at a head of a country or an army, then they are off on some fool mission — bringing civilization to the barbarians, making the world safe for democracy, or ushering in the proletarian revolution."

To get at an answer for why this happens, the authors turn to the work of the British anthropologist Robin Dunbar. Dunbar has studied the human animal, as also other primates like monkeys, chimpanzees, and baboons, and has come to the conclusion that there is a "maximum number of people and things with which the human brain can cope effectively." Though humans are very social animals, being in possession of a well-developed neocortex to deal with complex reasoning, we really have the capacity to effectively deal with only about 150 people. Dunbar has studied 21 different hunter-gatherer cultures and found the average number of people in their villages to be 148.4. And groups in modern societies seem to have picked up on this as well, from communal groups like the Hutterites to cohesive fighting units in militaries from the classical Roman army to the modern army company.

This is one of the most interesting parts of the book, and crucial to the central argument. "Human beings, according to the sociobiologists, cannot understand much more than the things about which they are concerned for their daily existence." Yet in our modern society individuals are put in positions in which they are asked to plan for millions of people and deal with dollar figures in the billions and even trillions. Dealing with all manner of things outside of their immediate circle, people are liable to accept inadequate or wrong explanations. "The human brain," the authors argue, "is just not big enough for the big world. In order to think, people are forced to start simplifying and eliminating a lot of detail. They have to abstract ... theorize ... generalize." And that's how mob mentality begins. And the problem with the mob, with crowds, is that "[t]hey can only feel and act. They can't think, because they have no set of facts solid enough on which to build." And at that point, the authors warn, "[s]logans replace reason. And the private world of right and wrong has been replaced by the public spectacle, which knows no moral authority beyond its own desires."