Our current models of physics have a number of free parameters in them, which simply have to be given some particular values by hand. (nakedpastor.com)
Because if we really want to see free parameters at work, we should take a look at how economic models are constructed. (realclimate.org)
The model assumes that solar irradiance variations are caused by surface magnetism and its single free parameter is kept at the same value for both cycles. (aanda.org)