Science and democracy are the right and left hands of what I'll refer to as the move from the realm of necessity to the realm of freedom.
Karl MarxThere are, besides, eternal truths, such as Freedom, , etc., that are common to all states of society. But Communism abolishes eternal truths, it abolishes all religion, and all morality, instead of constituting them on a new basis; it therefore acts in contradiction to all past historical experience.
Karl MarxThe abolition of religion as the illusory happiness of the people is the demand for their real happiness. To call on them to give up their illusions about their condition is to call on them to give up a condition that requires illusions. The criticism of religion is, therefore, in embryo, the criticism of that vale of tears of which religion is the halo.
Karl Marx