Stigler took exception to what he believed to be the confused image of the marketplace for ideas that was implicit in Capitalism and Freedom. If Friedman's popularization of Chicago neoclassical economics in his advice to the public was effective, this would imply that the public “underinvests” in knowledge—a market failure. But if agents maximize in collecting information (since his 1961 paper “The Economics of Information,” Stigler argued that they did), they will already have gathered all the information that it was appropriate for them to have. Friedman's efforts at popularization would be of no use to them. Worse still, Stigler believed any reference to market failure tended to provide intellectual support for objectionable efforts to expand regulation, and so popularizations of neoliberal views might turn out to be politically dangerous.

Dieter Plehwe, Quinn Slobodian & Philip Mirowski (eds.), Nine Lives of Neoliberalism, loc. 145