ABSTRACT
Keynes's theory, developed under the circumstances of depression in Britain and of the international crisis of the 1930s opposed a priori inflation and unemployment as alternative forms of disequilibrium. In 1958 Phillips, in his famous article, was to give a new expression to the dilemma by presenting it as a possible trade-off, a feasible substitution between two 'evils' according to economic policy preferences. The appearance in 1956 in the USA, then in several European countries, of rising inflation in a period of underemployment of resources dealt an early blow to this image of a symmetry between inflation and unemployment, but not until these disequilibria took on a new order of magnitude after 1970, and especially in 1974, did the adoption of the term 'stagflation' to denote the coexistence of stagnation and inflation, signal the abandonment of that image.
