From the October 1979 issue of the Socialist Standard
Nature builds no machines, no locomotives, railways, electric telegraphs, self-acting mules. These are products of human industry; natural material transformed into organs of the human will over nature, of human participation on nature. They are organs of the human brain, created by the human hand; the power of knowledge objectified. The development of fixed capital indicates to what degree general social knowledge has become a direct force of production and to what degree, hence, the conditions of the process of social life itself has come under the control of the General intellect and been transformed in accordance with it.
To what degree the powers of social production have been produced, not only in the form of knowledge, but also as immediate organs of social practice, of the real life process.
(The Making of Marx's Capital, p.706.)