These underlying conditions are, however, flexible because of changes both in the forces of production at men's command and in the knowledge of their use. It follows that the superstructure —the arrangement of social classes and the political institutions by which the existing order is maintained—must also change as the conditions of production are modified. But institutions, once established, are highly resistant to modification. The class structure of society and its political and social institutions there fore tend to lag behind the movement of economic change, until the accumulated disharmony forces drastic readjustment by the method of revolution. Then the entire superstructure is brought crashing down, and a new arrangement of classes and a new set of institutions in harmony with the new economic order arise.
Hegelianism.—The mechanism by which this process is carried into effect is the class-struggle. At this point Marx brings to his aid the Hegelian dialectic in which he had been trained. For Hegel, the history of the world is real only as a history of ideas. Each idea, as it is affirmed as truth, brings with it the idea that is its negation. The ideas do battle, and out of their con flict a new and higher idea arises, to be f ought and conquered in its turn. For this battle of ideas Marx substitutes a battle of economic forces, waged by means of the social classes which are the product of these forces. One set of economic forces raises a particular class to power, and this class makes a State in its own image, for the enforcement of its decrees upon the society as a whole. But no class can rule without bringing an antagonistic class into play.
Thus, modern capitalism cannot develop its powers without calling into being a proletariat—a working class depending solely on its wages for the means of life. This proletariat, moreover, must be gathered together in factory and mine, and organized into a co-operative force labouring to produce wealth for the capitalist. Thus concentrated and organized, it becomes a power, and develops a will of its own, contrary to the will of its capitalist masters. In time, it develops far enough to be able to dispense with these masters, and organize the changing and ever expand ing forces of production in a new way. It turns upon its masters, and in the fulness of time overthrows them, and sets up a new social and political superstructure corresponding to the new needs of the productive forces. This conception of the method of social and political change underlies the fierce invective of the Communist Manifesto of 1847, and indeed all Marx's writings on the practical strategy of socialism and revolution. It has also been the theoretical driving force behind the Communism of modern Russia, and finds dogmatic expression in the writings of Nikolai Lenin.
Marx's only general account of the Materialist Conception of History is found in a few pages of the Preface and Introduction to his Critique of Political Economy, the germ of his larger work, Capital. But the Communist Manifesto is mainly an
of it, while the historical chapters of the first volume of (13-15 and 26-32) are in essence an attempt to work out its bearing on the origin and growth of the capitalist system. The pamphlet Historic Materialism, by Marx's close collaborator and editor, Friedrich Engels, states the doctrine in a more systematic, if cruder form.
Surplus Value.—The doctrine of surplus value, which is the main theme of Capital, is best understood in close relation to Marx's doctrine of historical development and the class struggle.
According to the latter, the capitalist class is the exploiter and the labouring class the exploited which will in due time overthrow its rulers. The extraction of surplus value from the workers is the means by which this exploitation is accomplished. In seeking to prove that this exploitation exists, Marx takes his text from the classical economists of his own day, and especially from Ricardo and his less subtle popularises, M'Culloch. According to the classical doctrine, the value of commodities depends on the amount of labour involved in their production, and incor porated in them as finished products. Socialist writers before Marx, such as William Thompson and Thomas Hodgskin, had used this Ricardian doctrine as the basis for an assertion of the workers' "right to the whole produce of labour," and had treated the reward of the capitalists (rent, interest and profits) as sheer extortion, filched from the workers by means of the capitalists' social power.
Marx refines upon this view, and seeks to show that the ex tortion is made possible because, whereas all commodities sell at their value (apart from temporary market deviations) there is one peculiarity about the worker's only commodity, his labour power, that marks it off from all others. For this commodity alone has the power, in producing other commodities, to produce a value greater than it possesses itself. The value of the com modity, labour-power, is determined, like that of all other com modities, by the quantity of labour required for its production, or in other words, by the amount of labour required to enable the labourer to subsist and reproduce his kind. But the labourer produces by a day's work more than enough for his subsistence and the subsistence of his family. The capitalist, after paying him a subsistence wage, is able to keep for himself the rest of the labourer's product. This residue, the fund from which rent, interest and profits are drawn, Marx calls "surplus value." Sup pose, he says, the labourer works 12 hours a day, and only 6 hours are needed for his subsistence. The capitalist can then filch in the form of surplus value the product of 6 hours' labour. The rate of surplus value is i00% of the labourer's wage, and 5o% of the total product.