"although Jevons started his career a supporter of laissez-faire, by his last book [...] he had arrived at a position where he [...] found more and more contexts where state intervention was justified [...]: public health, working conditions, education, transport, and many others. Marshall, the dominant economist of the following generation, saw a smaller role for state intervention than did Jevons. However, he still assigned a significative role to the state, going along with the wider movement towards support for progressive taxation [...]. Though his socialism was somwhat limited, Walras even described himself as a socialist. If there was a causal link between socialism and marginalism, therefore, it did not involve marginalism being adopted as a way of defending laissez-faire against socialist criticism. Marginalism was used to argue in favour of social reform" (p. 270).
Backhouse deixa claro que a conexão que costumamos fazer entre marginalismo e laissez-faire não faz sentido. Nada como um pesquisador sério de HPE para nos explicar:
Backhouse, Roger (2002). The Penguin History of Economics. Penguin: London.