Plechanow formulates this very well in his “Beiträge der Geschichte des Materialismus.” He says: “The character of man’s natural environment determines the character of his productive activity, of his means of production. The means of production, however, determines the reciprocal relationships of men in the process of production as inevitably as the equipment of an army determines its entire organization, and all the relationships of the individuals of which it is made up. Now the reciprocal relations of men in the social process of production determine the entire structure of society. The influence of the natural environment upon this structure is therefore incontestable. The character of the natural environment determines that of the social environment. For example: ‘The necessity of computing the time of the rising of the Nile, created Egyptian astronomy and with it the domination of the priestly caste as guides in agriculture.’ “But this is only one side of the matter. Another side must also be considered if one is not to draw entirely false conclusions. The circumstances of production are the result, the productive forces are the cause. But the effect becomes a cause in its turn; the circumstances of production become a new source of the development of the productive forces. This leads to a double result. “1. The mutual influence of the circumstances of production and the productive forces causes a social movement, which has its own logic and a law of its own, independent of the natural environment. For example: Private property in the primitive phase of its development is always the fruit of the labor of the property-holder himself, as may be very well observed in the Russian villages. There necessarily comes a time, however, when it becomes the reverse of what it was before: it supposes the work of another, and becomes capitalistic private property, as we can likewise see any day in the Russian villages. This phenomenon is the effect of the immanent law of the evolution of private property. All that the natural environment can accomplish in this case consists in accelerating this movement through favoring the development of the productive forces. “2. Since the social evolution has its own logic, independent of any direct influence from the natural environment, it may happen that a people, though inhabiting the same land and retaining almost the same physical peculiarities, may have at different epochs of its history social and political institutions which are very little similar, or even totally different one from another.” [115]