The second feature of production is that its changes and development always begin with changes and development of the productive forces, and in the first place, with changes and development of the instruments of production. Productive forces are therefore the most mobile and revolutionary element of productions. First the productive forces of society change and develop, and then, depending on these changes and in conformity with them, men's relations of production, their economic relations, change. This, however, does not mean that the relations of production do not influence the development of the productive forces and that the latter are not dependent on the former. While their development is dependent on the development of the productive forces, the relations of production in their turn react upon the development of the productive forces, accelerating or retarding it. In this connection it should be noted that the relations of production cannot for too long a time lag behind and be in a state of contradiction to the growth of the productive forces, inasmuch as the productive forces can develop in full measure only when the relations of production correspond to the character, the state of the productive forces and allow full scope for their development. Therefore, however much the relations of production may lag behind the development of the productive forces, they must, sooner or later, come into correspondence with – and actually do come into correspondence with – the level of development of the productive forces, the character of the productive forces. Otherwise we would have a fundamental violation of the unity of the productive forces and the relations of production within the system of production, a disruption of production as a whole, a crisis of production, a destruction of productive forces.