Fine tuning is attributed to American economist Walter Heller (1915-1987), and is used to refer to a short-run interventionist approach to the economy using monetary and fiscal policies to control fluctuations in demand.
A popular policy of British governments from 1945 to 1970, it involved altering fiscal policy continually to stabilize national income as close to its full-employment potential as possible.
However, studies of the fine tuning policies in Britain during the 1950s and 1960s have shown little, if any, success. The main problem with fine tuning the economy is the difficulty of accurately gauging the magnitude and timing of fluctuations in demand.
Also see: demand theory
W W Heller, New Dimensions to Political Economy (New York, 1967)
The idea that naturalness will explain fine tuning was brought into question by Nima Arkani-Hamed, a theoretical physicist, in his talk “Why is there a Macroscopic Universe?”, a lecture from the mini-series “Multiverse & Fine Tuning” from the “Philosophy of Cosmology” project, a University of Oxford and Cambridge Collaboration 2013. In it he describes how naturalness has usually provided a solution to problems in physics; and that it had usually done so earlier than expected. However, in addressing the problem of the cosmological constant, naturalness has failed to provide an explanation though it would have been expected to have done so a long time ago.
The necessity of fine-tuning leads to various problems that do not show that the theories are incorrect, in the sense of falsifying observations, but nevertheless suggest that a piece of the story is missing. For example, the cosmological constant problem (why is the cosmological constant so small?); the hierarchy problem; and the strong CP problem, among others.
Also, Dongshan He’s team has suggested a possible solution for the fine tuned Cosmological constant by the universe creation from nothing model.
An example of a fine-tuning problem considered by the scientific community to have a plausible “natural” solution is the cosmological flatness problem, which is solved if inflationary theory is correct: inflation forces the universe to become very flat, answering the question of why the universe is today observed to be flat to such a high degree.
Although fine-tuning was traditionally measured by ad hoc fine-tuning measures, such as the Barbieri-Giudice-Ellis measure, over the past decade many scientists recognized that fine-tuning arguments were a specific application of Bayesian statistics