Some theorists consider
Karl Marx's thought to be divided into a
"young" period and a "mature" one. There is disagreement to when Marx's thought began to mature, and the problem of the idea of a "Young Marx" is the problem of tracking the development of Marx's works and of its possible unity. The problem thus centres on Marx's transition from
philosophy to
economics, which has been considered by orthodox Marxism as a progressive change towards
scientific socialism. This
positivist reading has however been challenged by
Marxist theorists, like members of the
New Left. They pointed out the humanist side in Marx's work, and how he in his early writings focused on liberation from
wage-slavery and freedom from
alienation, that they claimed was a forgotten element of Marx's writings and central to understanding his later work.