Comment by morbia

There is a philosophical discussion to be had about whether 19 physical parameters is "a lot", and another discussion about fine tuning. However, I was primarily referring to the artifical parameters that arise from doing real calculations (renormalisation scale, mass factorisation scale, PDFs etc). These plague pretty much all perturbative QCD calculations, and then particle physicists play games like varying them by a factor of 1/2 and 2 to get something that looks like error bars...