<P> The free - market economist Milton Friedman subsequently increased the popularity of the phrase by using it as the title of a 1975 book, and it is used in economics literature to describe opportunity cost . Campbell McConnell writes that the idea is "at the core of economics". </P> <Dl> <Dt> Science </Dt> </Dl> <P> In the sciences, TANSTAAFL means that the universe as a whole is ultimately a closed system . There is no magic source of matter, energy, light, or indeed lunch, that does not draw resources from something else, and that will not eventually be exhausted . Therefore, the TANSTAAFL argument may also be applied to natural physical processes in a closed system (either the universe as a whole, or any system that does not receive energy or matter from outside). (See Second law of thermodynamics .) The bio-ecologist Barry Commoner used this concept as the last of his famous "Four Laws of Ecology". </P> <P> According to American theoretical physicist and cosmologist Alan Guth "the universe is the ultimate free lunch", given that in the early stage of its expansion the total amount of energy available to make particles was very large . </P>

The adage there is no such thing as free lunch means