The criticism of Marx’s approach essentially boils down to the complaint that he is not an equilibrium economist. This criticism is quite correct. Marx has a fundamentally different method from neoclassical or post-Ricardian economists – dialectical economics.
Bourgeois economics uses as a central tool of analysis the concept of equilibrium – of capitalism in a state of rest. We regard Marxism as essentially based on the economy in a constant state of motion and therefore in permanent disequilibrium – or rather a condition where the notion of equilibrium has no meaning.
Economists, with outstanding exceptions such as Marx, have usually set out to glorify capitalism. They tend to conclude that it will automatically produce full employment and increasing prosperity – so long as nobody messes about with its workings. That is the outlook of monetarism. But Marxists believe that Keynesianism doesn’t work either. It doesn’t work because capitalism can’t be made to work. The problem of capitalism in crisis is not just a matter of inadequate demand - of markets - it’s a problem of profitable markets.