them, Feuerbach differed from Hegel in arguing that worship of God is itself a form of alienation, because it projects human qualities on to an external idea, rather than realising them as part of the self. Marx Marx was initially in the Young Hegelian camp and, like Feuerbach, rejected the spiritual basis, and adapted Hegel's dialectic model to a theory of (historical) materialism. Marx's theory of alienation is articulated most clearly in the Economic and Philosophic Manuscripts of 1844 and The German Ideology (1846). The 'young' Marx wrote more often and directly of alienation than the 'mature' Marx, which some regard as an ideological break while others maintain that the concept remained central. Structuralists generally hold that there was a transition from a philosophical-anthropological (Marxist humanism) concept (e.g. internal alienation from the self) to a structural-historical interpretation (e.g. external alienation by appropriation of labor), accompanied by a change in terminology from alienation to exploitation to commodity fetishism and reification. Marx's concepts of alienation have been classed into four types by Kostas Axelos: economic and social alienation, political alienation, human alienation, and ideological alienation. In the concept's most prominent use, it refers to the economic and social alienation aspect in which workers are disconnected from what they produce and why they produce. Marx believed that alienation is a systematic result of capitalism. Essentially, there is an "exploitation of men by men" where the division of labor creates an economic hierarchy. His theory of alienation was based upon his observation that in emerging industrial production under capitalism, workers inevitably lose control of their lives and selves by not having any control of their work. Workers never become autonomous, self-realized human beings in any significant sense, except in the way the bourgeoisie wants the worker to be realized. His theory relies on Feuerbach's The Essence of Christianity (1841), which argues that the idea of God has alienated the characteristics of the human being. Stirner would take the analysis further in The Ego and Its Own (1844), declaring that even 'humanity' is an alienating ideal for the individual, to which Marx and Engels responded in The German Ideology (1845). Alienation in capitalist societies occurs because in work each contributes to the common wealth but they can only express this fundamentally social aspect of individuality through a production system that is not publicly social but privately owned, for which each individual functions as an instrument,