Set of material forces that allow the transformation of Nature by the human species within the framework of a certain mode of production. The main productive forces are always human work and knowledge substantiated in means of production through technology.
Development of the productive forces
The development of productive forces is measured by the potential capacity to transform the environment. That is, by the average physical productivity of labor, the amount of production that is capable of adding one hour of abstract social work. More precisely, by an average hour under the normal conditions of production prevailing in a given society and with the average social degree of skill and labor intensity.http://dictionary.marxismo.school/Productive forces