There is a familiar tale told by some Marxists — capitalism will come to an end when it no longer permits the development of productive forces. As described by G.A. Cohen in his book, Karl Marx's Theory of History: a Defence, the thesis of "the primacy of productive forces' proposes that the existence of a set of productive relations is explained by the level of development of the productive forces and that a new set of relations of production emerges when the old set "fetters' the productive forces (Cohen, 1978).