The main philosophical context for Marx was the thought of Hegel, which Marx modified in a crucial respect: he removed its idealist perspective. Marx can also, however, be placed in a much longer philosophical tradition, which takes us back to the ancient Greeks, for in his doctoral thesis he engaged with pre-Platonic and post-Platonic thought. The entire thrust of Marx's argumentation is anti-Platonic, and it cannot be sufficiently emphasized how Marx saw his work as a contribution to the science of economics. For Marx, there is no path out of the cave, for there is nothing outside the cave: rather, the revolutionary politics he and Engels espoused aimed at changing how the prisoners governed themselves, and the Marxist conception of liberation is entirely materialist and immanent.