An immense amount of material bearing on this is contained in all the works of Marx, particularly in the four volumes of his correspondence with Engels, published in 1913. This material is still far from having been brought together, collected, examined and studied. We shall therefore have to confine ourselves here to the most general and brief remarks, emphasizing that Marx justly considered that, without this aspect, materialism is incomplete, one-sided, and lifeless. The fundamental task of proletarian tactics was defined by Marx in strict conformity with all the postulates of his materialist-dialectical Weltanschauung . Only an objective consideration of the sum total of the relations between absolutely all the classes in a given society, and consequently a consideration of the objective stage of development reached by that society and of the relations between it and other societies, can serve as a basis for the correct tactics of an advanced class.
Competition divides their interests.
Once it has reached this point, association takes on a political character. In Germany, Marx, in 1848 and 1849, supported the extreme revolutionary democrats, and subsequently never retracted what he had then said about tactics.