I will add a remark on the second point. Many will think that if historical materialism is reduced to the limits within which we have confined it, it will not only no longer be a legitimate and real scientific theory (which we are indeed prepared to grant) but will actually lose all importance whatever, and against this second conclusion we once more, as we have done already on another occasion, make vigorous protest. Undoubtedly the horror expressed by some for pure science and for abstractions is inane, since these intellectual methods are indispensable for the very knowledge of concrete reality; but no less inane is the complete and exclusive worship of abstract propositions, of _definitions_, of _theorems_, of _corollaries_: almost as if these constituted a sort of aristocracy of human thought. Well! the economic purists (not to draw examples from other fields, though numbers could be found in pure mathematics) prove to us, in fact, that the discovery of scientific theorems,--strictly, unimpeachably scientific,--is frequently neither an over-important nor over-difficult matter. To be convinced thereof we need only remark how many _eponimi_ of new theorems issue from every corner of the German or English schools. And concrete reality, _i.e._ the very world in which we live and move, and which it concerns us somewhat to know, slips out, unseizable, from the broad-meshed net of abstractions and hypotheses. Marx, as a sociologist, has in truth not given us carefully worked out definitions of _social phenomena_, such as may be found in the books of so many contemporary sociologists, of the Germans Simmel and Stammler, or of the Frenchman Durckheim; but he teaches us, although it is with statements approximate in content and paradoxical in form, to penetrate to what society is in its _actual truth_. Nay, from this point of view, I am surprised that no one has thought of calling him 'the most notable _successor_ of the Italian Niccolo Machiavelli'; a Machiavelli of the labour movement.