Engels, who outlived him by twelve years, edited the two last volumes of "Capital," while Karl Kautsky, the disciple and successor of Engels and the real disseminator of Marxian doctrines, edited the three volumes of Marx's historical studies on surplus value. The latter work is not far short of being a great history of political economy. FOOTNOTES: [6] By democratic parties were then understood working-class political movements, such as Chartism, etc. IV. THE MARXIAN SYSTEM. I. THE MATERIALIST CONCEPTION OF HISTORY. As a guide to his studies from 1843-4 onwards, Marx used the conception of history, or method of investigation, which--in contradistinction to the idealist conception of history of Hegel--was named materialistic. As its nature is dialectic--as it seeks to conceive in thought the evolving antagonisms of the social process--it is, like Hegel's dialectic, a conception of history and a method of investigation at the same time. Nowhere did Marx work out his method of investigation in a special and comprehensive form; the elements of it are scattered throughout his writings, particularly in the Communist Manifesto and in the "Poverty of Philosophy," and serve the purpose of polemics or demonstration. Only in the preface to his book, "On the Critique of Political Economy" (1859) did he devote two pages to a sketch of his conception of history, but in phraseology which is not always clear, sequential, or free from objection. It was the intention of Marx to write a work on Logic, where he would certainly have formulated clearly his materialistic dialectic. As, however, his fundamental ideas on this subject are available, we are able to extract the essentials of his position. A glance over human history suffices to teach us that from age to age man has held to be true or false various opinions on rights, customs, religion, the State, philosophy, land-holding, trade, industry, etc., that he has had various economic arrangements, and forms of the State and of society, and that he has gone through an endless series of struggles and wars and migrations. How has this complicated variety of human thought and action come about? Marx raises that question, which, so far as he is concerned, does not aim in the first place at the discovery of the origin of thought, of rights, of religion, of society, of trade, etc.; these he takes to be historically given. He is rather concerned to find out the causes, the impulses, or the springs which produce the changes and revolutions of the essentials and forms of the mental and social phenomena, or which create the tendencies thereto. In a sentence: What interested Marx here was not the _origin_, but the development and change of things--he is searching for the dynamic law of history.