" In previous chapters I have mentioned moral positivism (especially that of Hegel), the theory that there is no moral standard but the one which exists; that what is, is reasonable and good; and therefore, that might is right. The practical aspect of this theory is this. A moral criticism of the existing state of affairs is impossible, since this state itself determines the moral standard of things. Now the historicist moral theory we are considering is nothing but another form of moral positivism. For it holds that coming might is right. The future is here substituted for the present—that is all. And the practical aspect of the theory is this. A moral criticism of the coming state of affairs is impossible, since this state determines the moral standard of things. The difference between ‘the present’ and ‘the future’ is here, of course, only a matter of degree. One can say that the future starts to-morrow, or in 500 years, or in 100. In their theoretical structure there is no difference between moral conservatism, moral modernism, and moral futurism. Nor is there much to choose between them in regard to moral sentiments. If the moral futurist criticizes the cowardice of the moral conservative who takes sides with the powers that be, then the moral conservative can return the charge; he can say that the moral futurist is a coward since he takes sides with the powers that will be, with the rulers of to-morrow. I feel sure that, had he considered these implications, Marx would have repudiated historicist moral theory. Numerous remarks and numerous actions prove that it was not a scientific judgement but a moral impulse, the wish to help the oppressed, the wish to free the shamelessly exploited and miserable workers, which led him to socialism. I do not doubt that it is this moral appeal that is the secret of the influence of his teaching. And the force of this appeal was tremendously strengthened by the fact that he did not preach morality in the abstract. He did not pretend to have any right to do so. Who, he seems to have asked himself, lives up to his own standard, provided it is not a very low one? It was this feeling which led him to rely, in ethical matters, on under-statements, and which led him to the attempt to find in prophetic social science an authority in matters of morals more reliable than he felt himself to be. Surely, in Marx’s practical ethics such categories as freedom and equality played the major rôle. He was, after all, one of those who took the ideals of 1789 seriously. And he had seen how shamelessly a concept like ‘freedom’ could be twisted. This is why he did not preach freedom in words—why he preached it in action. He wanted to improve society and improvement meant to him more freedom, more equality, more justice, more security, higher standards of living, and especially that shortening of the working day which at once gives the workers some freedom. It was his hatred of hypocrisy, his reluctance to speak about these ‘high ideals’, together with his amazing optimism, his trust that all this would be realized in the near future, which led him to veil his moral beliefs behind historicist formulations. "
― Karl Popper , The Open Society and Its Enemies