Nicholas Georgescu-Roegen was born in Constanța (Romania) in 1906. He was Professor of Economics at the University of Nashville (Tennessee, USA). He died in 1994 in the US. He held that economic calculations should include nature because matter and energy form part of the economic and productive process in a state of low entropy and leave it as high entropy. Because entropy is irreversibly increasing, no natural resource – not even free solar energy – can be considered a ‘fund’. Only matter-energy is a fund, in the strict sense of the term, that is, in a relativistic relation in which matter can transform itself into energy and vice versa. He believed that only work creates value and that those who have worked have been doubly industrious, given that they used their intellect and not only their muscles and energy.