Since these conditions correspond at every stage to the simultaneous development of the productive forces, their history is at the same time the history of the evolving productive forces taken over by each new generation, and is, therefore, the history of the development of the forces of the individuals themselves.
Since this evolution takes place naturally, i.e. is not subordinated to a general plan of freely combined individuals, it proceeds from various localities, tribes, nations, branches of labour, etc. each of which to start with develops independently of the others and only gradually enters into relation with the others. Furthermore, it takes place only very slowly; the various stages and interests are never completely overcome, but only subordinated to the prevailing interest and trail along beside the latter for centuries afterwards. It follows from this that within a nation itself the individuals, even apart from their pecuniary circumstances, have quite different developments, and that an earlier interest, the peculiar form of intercourse of which has already been ousted by that belonging to a later interest, remains for a long time afterwards in possession of a traditional power in the illusory community (State, law), which has won an existence independent of the individuals; a power which in the last resort can only be broken by a revolution. This explains why, with reference to individual points which allow of a more general summing-up, consciousness can sometimes appear further advanced than the contemporary empirical relationships, so that in the struggles of a later epoch one can refer to earlier theoreticians as authorities.
On the other hand, in countries which, like North America, begin in an already advanced historical epoch, the development proceeds very rapidly.
Such countries have no other natural premises than the individuals, who settled there and were led to do so because the forms of intercourse of the old countries did not correspond to their wants. Thus they begin with the most advanced individuals of the old countries, and, therefore, with the correspondingly most advanced form of intercourse, before this form of intercourse has been able to establish itself in the old countries.
This is the case with all colonies, insofar as they are not mere military or trading stations. Carthage, the Greek colonies, and Iceland in the eleventh and twelfth centuries, provide examples of this. A similar relationship issues from conquest, when a form of intercourse which has evolved on another soil is brought over complete to the conquered country: whereas in its home it was still encumbered with interests and relationships left over from earlier periods, here it can and must be established completely and without hindrance, if only to assure the conquerors' lasting power. (England and Naples after the Norman conquest. when they received the most perfect form of feudal organisation.)
This contradiction between the productive forces and the form of intercourse, which, as we saw, has occurred several times in past history, without, however, endangering the basis, necessarily on each occasion burst out in a revolution, taking on at the same time various subsidiary forms, such as all-embracing collisions, collisions of various classes, contradiction of consciousness, battle of ideas, etc., political conflict, etc. From a narrow point of view one may isolate one of these subsidiary forms and consider it as the basis of these revolutions; and this is all the more easy as the individuals who started the revolutions had illusions about their own activity according to their degree of culture and the stage of historical development.
Thus all collisions in history have their origin, according to our view, in the contradiction between the productive forces and the form of intercourse.
Incidentally, to lead to collisions in a country, this contradiction need not necessarily have reached its extreme limit in this particular country.
The competition with industrially more advanced countries, brought about by the expansion of international intercourse, is sufficient to produce a similar contradiction in countries with a backward industry (e.g. the latent proletariat in Germany brought into view by view by the competition of English industry).
Conquest This whole interpretation of history appears to be contradicted by the fact of conquest. Up till now violence, war, pillage, murder and robbery, etc. have been accepted as the driving force of history. Here we must limit ourselves to the chief points and take, therefore, only the most striking example -- the destruction of an old civilisation by a barbarous people and the resulting formation of an entirely new organisation of society.
(Rome and the barbarians; feudalism and Gaul; the Byzantine Empire and the Turks.)
With the conquering barbarian people war itself is still, as indicated above, a regular form of intercourse, which is the more eagerly exploited as the increase in population together with the traditional and, for it, the only possible, crude mode of production gives rise to the need for new means of production. In Italy, on the other hand, the concentration of landed property (caused not only by buying-up and indebtedness but also by inheritance, since loose living being rife and marriage rare, the old families gradually died out and their possessions fell into the hands of a few) and its conversion into grazing land (caused not only by the usual economic forces still operative today but by the importation of plundered and tribute-corn and the resultant lack of demand for Italian corn) brought about the almost total disappearance of the free population. The very slaves died out again and again, and had constantly to be replaced by new ones.