  Sensitivity to the square of the cutoff scale of quantum corrections of the
Higgs boson mass self-energy has led many authors to conclude that the Higgs
theory suffers from a naturalness or fine-tuning problem. However, speculative
new physics ideas to solve this problem have not manifested themselves yet at
high-energy colliders, such as the Large Hadron Collider at CERN. For this
reason, the role of naturalness as a guide to theory model-building is being
severely questioned. Most attacks suggest that one should not resort to
arguments involving gravity, which is a much less understood quantum field
theory. Another line of attack is against the assumption that there exists a
multitude of additional heavy states specifically charged under the Standard
Model gauge symmetries. Nevertheless, if we give ground on both of these
assaults on naturalness, what remains is a naturalness concern over the
prospect of numerous additional spin-zero scalar states in nature. The
proliferation of heavy scalars generically destabilizes the Higgs boson mass,
raising it to the highest and most remote scalar mass values in nature, thus
straining the legitimacy of the Standard Model. The copious use of extra
scalars in theory model building, from explaining flavor physics to providing
an inflationary potential and more, and the generic expectation of extra scalar
bosons in nature argues for the proliferation instability problem being the
central concern for naturalness of the Standard Model. Some approaches to
solving this problem are presented.
