A Contribution to the Critique of Hegel's Philosophy of Right
A Contribution to the Critique of Hegel's Philosophy of Right, written throughout 1843-1844, was Marx's critique of Hegelian Idealism, a philosophy whom he once followed, but later strayed from and criticized. In his critique, Marx focuses on Hegel's theory of the state, which argued in abstract terms that states were the embodiment of all that society considered rational, and were guided by a metaphysical "World Spirit."
Marx begins by discussing the role of religion in society, that is, as a relief from pain. Here he famously states, "Religion is the sigh of the oppressed creature, the heart of a heartless world, the spirit of spiritless conditions. It is the opium of the people." He discusses criticism of religion and accepts its basic arguments, but argues that religion, being a relief from human suffering, is a reflection of the real world, and thus, "The criticism of religion is, therefore, in embryo, the criticism of that vale of tears of which religion is the halo."
The rest of the introduction is devoted to a criticism of Germany's current political and intellectual state, which he views as backwards, as well as a criticism of philosophical political movements, specifically the Hegelian, which he views as using only insufficient philosophical criticism rather than concrete political action, their mistake being summed up "In a word – You cannot abolish philosophy without making it a reality."