The authors point out that the QWERTY example is currently the most favored by those arguing for government intervention. By attacking the QWERTY example, the authors are attacking the case for government intervention.<p>&#62; Stanford University economist Paul Krugman offered the central claim of this literature boldly and with admirable simplicity: "In QWERTY worlds, markets can't be trusted." The reason that he uses "QWERTY worlds," and not DOS worlds, or VHS worlds, is that the DOS and VHS examples are not very compelling. Almost no one uses DOS anymore, and many video recorder purchasers thought VHS was better than Beta (as it was, in terms of recording time, as we have discussed at length elsewhere).<p>In an argument about government intervention, the burden of proof should always be on those arguing for government intervention because they are arguing that freedom should be restricted. To take a simple example, if you publish something on the Internet and I want the government to force you to take it down, the burden should be on me to show why the government should interfere with you. If I don't make a case that is more convincing than yours, you should be left alone. I should not be allowed to require that you prove why you should be allowed to publish.<p>This is an important distinction because freedom often depends on this. Many activities that free people engage in would not happen if people had to ask permission first-- either because there is no plausible reason why the particular activity should be allowed, or just because it would not be worth the trouble.<p>In a free society, government must have a good reason to prohibit. In a non-free society, people must have a good reason to get permission. The authors are assuming a free society, so they content themselves with attacking government's reasons to prohibit.