Should governments accept the principle of devoting a proportion of their resources to funding basic research? From the standpoint of economics, science should be considered as a public good and for that reason it should be protected from market forces. This article tries to show that this result can only be maintained at the price of abandoning arguments traditionally deployed by economists themselves. It entails a complete reversal of our habitual ways of thinking about public goods. In order to bring (...) this reversal about, this article draws on the central results obtained by the anthropology and sociology of science and technology over the past several years. Science is a public good, not because of its intrinsic properties but because it is a source of diversity and flexibility. (shrink)