The physiocrats are troubled by difficulties of another nature. As the actually first systematic spokesmen of capital, they attempt to analyse the nature of surplus-value in general. For them, this analysis coincides with the analysis of rent, the only form of surplus-value which they recognise. Therefore, they consider rent-yielding, or agricultural, capital to be the only capital producing surplus-value, and the agricultural labour set in motion by it, the only labour producing surplus-value, which from a capitalist viewpoint is quite properly considered the only productive labour. They are quite right in considering the creation of surplus-value as decisive. Apart from other merits to be set forth in Book IV, they deserve credit primarily for going back from merchant’s capital, which functions solely in the sphere of circulation, to productive capital, in opposition to the mercantile system, which, with its crude realism, constitutes the actual vulgar economy of that period, pushing into the background in favour of its own practical interests the beginnings of scientific analysis made by Petty and his successors. In this critique of the mercantile system, incidentally, only its conceptions of capital and surplus-value are dealt with. It has already been indicated previously that the monetary system correctly proclaims production for the world-market and the transformation of the output into commodities, and thus into money, as the prerequisite and condition of capitalist production. In this system’s further development into the mercantile system, it is no longer the transformation of commodity-value into money, but the creation of surplus-value which is decisive — but from the meaningless viewpoint of the circulation sphere and, at the same time, in such manner that this surplus value is represented as surplus money, as the balance of trade surplus. At the same time, however, the characteristic feature of the interested merchants and manufacturers of that period, which is in keeping with the stage of capitalist development represented by them, is that the transformation of feudal agricultural societies into industrial ones and the corresponding industrial struggle of nations on the world-market depends on an accelerated development of capital, which is not to be arrived at along the so-called natural path, but rather by means of coercive measures. It makes a tremendous difference whether national capital is gradually and slowly transformed into industrial capital, or whether this development is accelerated by means of a tax which they impose through protective duties mainly upon landowners, middle and small peasants, and handicraftsmen, by way of accelerated expropriation of the independent direct producers, and through the violently accelerated accumulation and concentration of capital, in short by means of the accelerated establishment of conditions of capitalist production. It simultaneously makes an enormous difference in the capitalist and industrial exploitation of the natural national productive power. Hence the national character of the mercantile system is not merely a phrase on the lips of its spokesmen. Under the pretext of concern solely for the wealth of the nation and the resources of the state, they, in fact, pronounce the interests of the capitalist class and the amassing of riches in general to be the ultimate aim of the state, and thus proclaim bourgeois society in place of the old divine state. But at the same time they are consciously aware that the development of the interests of capital and of the capitalist class, of capitalist production, forms the foundation of national power and national ascendancy in modern society.