  Citing the disappearance of a sharp peak in the electron self-energy,
extracted from optics and angle-resolved photoemission spectroscopy (ARPES)
experiments in deeply over-doped copper-oxide superconductors with Tc of
55-60K, Hwang, Timusk et al. argue that sharp modes, be they phononic or
magnetic in origin, are not important for superconductivity in the cuprates. If
true, this would have been an important progress. We show, however, their
conclusions are unfounded because of the insensitivity of the optics experiment
in studying strongly anisotropic material like the cuprates, and a
misrepresentation of existing ARPES data. In an added note, we refute the claim
by Valla, Timusk et. al. that the doping level of the data presented in the
first part of this comment is lower than reported.
