In this paper I propose to investigate the problem of liberty in Adam Smith's work. Suggesting that there is a “problem” may strike some as strange. After all, is not Smith simply the great defender of the system of natural liberty, a set of economic proposals that would remove the State from the business of directing the economy? Does he not maintain unequivocally that individuals are the best judges of their own self-interest and argue that they should be allowed to commit their labor and capital to those enterprises they deem most useful? Is Smith not one of the great defenders of the concept of negative liberty in modern liberal thought?

Since the 1980s, institutional change has become a matter of great interest as economists faced the necessity and the challenge to provide a theory of economic or cultural evolution. Their first reaction was to refer to biology, a field in which theories of evolution have reached a high degree of sophistication. This was all the more legitimate and relevant given that biology has been largely influenced by economics (Schweber 1977, 1980; Gordon 1991; Kresge and Wenar 1994; Depew and Weber 1995). Indeed, the influence of classical political economy on the views of one of the fathers of the modern theory of evolution, Charles Darwin, is widely admitted. Darwin borrowed from economists fundamental ideas such as spontaneous order and methodological individualism (from Adam Smith), the positive role of diversity and variety (from Charles Babbage) and the concept of the struggle for life (from Thomas Malthus). Therefore, the ideas promoted by the founding fathers of political economy, sometimes called “Darwinians before Darwin” (Hayek 1973, p. 23), have shaped Darwin's theory of biological evolution.

The ideal of Political Economy is not unrestricted competition, but competition that is truly free, because controlled by justice and by law. The distinction between freedom and license needs to be preserved in this department of political philosophy. With that distinction clearly maintained, we may still retain, in economics as in politics, our beautiful watchword, liberty (John Bates Clark 1879, p. 167).

John Bates Clark has had a formidable impact on the development of economic theory and the theory of income distribution. In addition, Clark's marginal product theory of distribution has often played an instrumental role in the defense of laissez-faire policies. His theory has been used to criticize a wide variety of market interventions, including minimum wage legislation. As a result it is not surprising that Clark's theory of income distribution, and Clark himself, have drawn more than a few critics.