Second of all, invoking "externalities" verges on intellectual fraud insofar as, in human societies, practically everything generates externalities. If I am in good health, I can work, so I call on society to finance my health. But if I have children and educate them well, there will be workers in the future, which is useful for society, so I call on society to subsidize my parenthood and I ask for all sorts of parental allocations. At this rate, I can get everything subsidized, since it is always possible to invoke some positive externality, which is to say, some result of my private decision that benefits others. In effect, if I am happy and fulfilled, I will not attack my fellows and I will be fully productive in my work. It is therefore society's responsibility to see to my happiness… We're talking here of positive externalities, but the existence of negative externalities is used to justify the regulation of behaviour, and notably the multiplication of prohibitions to the extent that my private decisions have side effects that harm others.

          It is not a matter of questioning the existence of externalities, even if their precise measurement poses real problems, severely limiting the applicability of this type of theory. But we must realize here too that the existence of externalities is not specifically a market phenomenon. We can even suggest that the market itself exists in part to take advantage of this phenomenon, since competition can be seen as a positive externality issuing from the division of labour. Furthermore, to pretend that government action can correct externalities generated by the market is to posit once again that this state intervention does not itself generate externalities. By what miracle? Nobody knows.

          Government intervention implies public financing and the establishment of a technocracy, which entails an increase in the tax burden, which in turn sets off a whole series of negative externalities (tax evasion, corruption, the development of an underground economy, the modification of the way people think, the crowding out effect…). How can we know whether the sum of these negative externalities is not more costly and more serious than the initial problem that motivated and justified the state's intervention?

          In practice, it can be observed that in a growing number of areas, market mechanisms are being reintroduced to compensate for the accumulated failures of public management, in flagrant opposition to the official dogma that posits the need to call on the government to correct for market failures.