In the Daily Mail of 13 March 1931, he called the assumption of perfect sectoral labour mobility "nonsense" since it states that a person made unemployed contributes to a reduction in the wage rate until he finds a job. But for Keynes, this change of job may involve costs (job search, training) and is not always possible. Generally speaking, for Keynes, the assumptions of full employment and automatic return to equilibrium discredit the theory of comparative advantage.
