of value incorporating ideas drawn from Austrian economics. Some left-Rothbardians are mutualists whereas other left-Rothbardians and market-oriented left-libertarians have declined to embrace mutualist views of real property while sharing the mutualist opposition to corporate hierarchies and wealth concentration. Those left-libertarians have placed particular emphasis on the articulation and defense of a libertarian theory of class and class conflict, although considerable work in this area has been performed by libertarians of other persuasions. Those left-Rothbardians and libertarians maintain that because of its heritage and its emancipatory goals and potential radical market anarchism should be seen by its proponents and by others as part of the socialist tradition and that market anarchists like anarcho-capitalists can and should call themselves socialists, echoing the language of libertarian socialists like American individualist anarchists Benjamin Tucker and Lysander Spooner and British Thomas Hodgskin. Some of those left-Rothbardians have used Rothbardian arguments such as the homestead principle and a labor theory of property to support anarchist concepts such as workers' self-management. In response to claims from anarcho-capitalists that he uses the term capitalism incorrectly, Kevin Carson says he is deliberately choosing to resurrect what he claims to be an old definition of the term in order to "make a point". He claims that "the term 'capitalism,' as it was originally used, did not refer to a free market, but to a type of statist class system in which capitalists controlled the state and the state intervened in the market on their behalf". Carson holds that "capitalism, arising as a new class society directly from the old class society of the Middle Ages, was founded on an act of robbery as massive as the earlier feudal conquest of the land. It has been sustained to the present by continual state intervention to protect its system of privilege without which its survival is unimaginable". In addition to individualist anarchist Benjamin Tucker's big four monopolies (land, money, tariffs and patents), Carson argues that the state has also transferred wealth to the wealthy by subsidizing organizational centralization in the form of transportation and communication subsidies, arguing that in a truly laissez-faire system the ability to extract a profit from labor and capital would be negligible. In response to criticism from anarcho-capitalists who reject the labor theory of value in favor of the subjective theory of value and support marginalism, the theoretical sections of Carson's Studies in Mutualist Political Economy are presented