The autonomous character of science - its ‚genuine‘ scientific character - can only be guaranteed, if one arrives at a consistent formulation of an exclusive purpose of science and a functional methodology. The most thoroughgoing attempts at solving this complex problem have been undertaken in the context of ‚critical rationalism‘, in particular by POPPER and LAKATOS. It can be shown, however, that both attempts fail in every respect. Their purpose to constitute science as a self-regulative system and to make it ‚waterproof‘ with respect to social and individual influences of all kind, ends up in logical fallacies, theoretical contradicitions, or metaphysical postulates.