This article deals with the theoretical basis of a recent labour market reform proposal: the transitional labour markets (TLM), developed in Europe since 1995. TLM are the systematic and negociated management of transitions in and around the labour market, and of professional and personal careers. The core argument relies on the opposition set out by the philosopher M. Foucault, who made a strong distinction between the consciousness of scarcity (typical of the 19^th century) and the scarcity of consciousness (prevailing since the 20^th century). The first section examines three scarcities typical of the present time, as they are developed by three outstanding economists : scarcity of time (G. Becker), of attention (H. A. Simon), and of freedom (A. K. Sen). These scarcities are analysed and illustrated by references to work and poverty stakes. In the second section, we show how TLM allow to manage these three new forms of scarcity, through the management of careers, the collective organization of the labour market flexibility, the entitlement to social drawing rights and the empowerment of the disadvantaged.