To understand these losses in extreme isolation, the easiest case to understand is Japan, because the loss of firearms in Japan was witnessed and described. It took place in a literate society. Guns arrived in Japan around 1543 with two Portuguese adventurers who stepped ashore, pulled out a gun, and shot a duck on the wings. A Japanese nobleman happened to be there, was very impressed, bought these two guns for $10,000, and had his sword-maker imitate them. Within a decade, Japan had more guns per capita than any other country in the world, and by the year 1600 Japan had the best guns of any country in the world. And then, over the course of the next century, Japan gradually abandoned guns.

What happened was that the Samurai, the warrior class in Japan, had been used to fighting by standing up in front of their armies and making a graceful speech, the other opposing Samurai made an answering graceful speech, and then they had one-on-one combat. The Samurai discovered that the peasants with their guns would shoot the Samurai while the Samurai were making their graceful speeches. So the Samurai realized that guns were a danger because they were such an equalizer. The Samurai first restricted the licensing of gun factories to a hundred factories, and then they licensed fewer factories, and then they said that only three factories could repair guns, and then they said that those three factories could make only a hundred guns a year, then ten guns a year, then three guns a year, until by the 1840s when Commodore Perry came to Japan, Japan no longer had any guns. That represents the loss of a very powerful technology.

This loss was possible only in Japan because of its isolation; there were no other neighbors threatening Japan. When firearms arrived in Europe, there were European princes who similarly banned firearms, and there were European princes who banned printing, but you can guess what happened. When a prince in the middle of Europe banned firearms, within a short time the prince next door who did not ban firearms either walked in and conquered, or else the prince who banned firearms quickly realized his or her mistake and reacquired firearms from next door. The banning of the guns could work only in isolated Japan, where there were no neighbors as a threat, and where there were no neighbors from whom to reacquire the technology.

So these stories of isolated societies illustrate two general principles about relations between human group size and innovation or creativity. First, in any society except a totally isolated society, most innovations come in from the outside, rather than being conceived within that society. And secondly, any society undergoes local fads. By fads I mean a custom that does not make economic sense. Societies either adopt practices that are not profitable or for whatever reasons abandon practices that are profitable. But usually those fads are reversed, as a result of the societies next door without the fads out-competing the society with the fad, or else as a result of the society with the fad, like those European princes who gave up the guns, realizing they're making a big mistake and reacquiring the fad. In short, competition between human societies that are in contact with each other is what drives the invention of new technology and the continued availability of technology. Only in an isolated society, where there's no competition and no source of reintroduction, can one of these fads result in the permanent loss of a valuable technology. So that's one of the two sets of lessons that I want to draw from history, about what happens in a really isolated society and group.