"The strength of the Friedman's critique of active policy does not lie in general principles or broad sweeps of history. It lies in the itemization of government failures: industrial regulation that is primarily in the interests of the special groups regulated, inefficient post offices, disappointing schools, welfare " messes," the failure of public housing. To some extent the Friedmans document these changes; to a greater extent they rely on current popular perceptions. These failures are in part real, and the Friedmans are not wrong in suggesting that the pursuit of social goals is very apt to be carried on much less efficiently than the pursuit of one's own self-interest. They do not question the theoretical need for internalization of externalities, as in pollution, but argue that the arrangements are bound to be inefficient (actually, they are rather muted on this particular argument, and nowhere flatly assert that the social gains do not exceed the costs). They are strongly opposed to testing drugs for efficacy but do not seem to question testing them for safety. In short, the critique tends to be selective, They are very ingenious at suggesting alternative policies for some problems, such as the voucher system for elementary education, the negative income tax to replace welfare, or the abolition of licensing for physicians. But when advocating comprehensive changes, it is important to consider the effects on the entire system."