Karl Popper on Karl Marx - a short passage

Karl Popper was first and foremost a philosopher of science, which makes his criticisms of pseudo-scientific theories of society especially powerful. In his book The Open Society and Its Enemies, Popper takes apart many social theories, including the 'prophecies' of Karl Marx. It is remarkable however how complimentary and sympathetic he is towards Marx.

This following passage from The Open Society and Its Enemies sums up Popper's attitude towards Marx very nicely, and I thought it was worth posting up here.

“[Marx underrated] the significance of his own moral ideas; for it cannot be doubted that the secret of his religious influence was in its moral appeal, that his criticism of capitalism was effective mainly as a moral criticism. Marx showed that a moral system can as such be unjust; that if the system is bad, then all the righteousness of the individuals who profit from it is a mere sham righteousness, is mere hypocrisy. For our responsibility extends to the system, to the institutions which we allow to persist.
"It is this moral radicalism of Marx which explains his influence; and that is a hopeful fact in itself. This moral radicalism is still alive. It is our task to keep it alive, to prevent it from going the way which his political radicalism will have to go. ‘Scientific’ Marxism is dead. Its feeling of social responsibility and its love for freedom must survive."