  In our paper (W\"olfle and Balatsky, Phys. Rev. B 98, 104505 (2018)) we
presented a microscopic theory of superconductivity for doped SrTiO$_{3}$ by
proposing two pairing mechanisms acting simultaneously with relative strength
depending on the closeness to the ferroelectric quantum critical point. The
first mechanism rests on the dynamically screened Coulomb interaction, and the
second assumed a coupling to the soft transverse optical phonon. In their
comment Ruhman and Lee point out an error in our estimate of the deformation
potential coupling to the soft mode. We agree that this type of coupling cannot
explain the gigantic isotope effect observed experimentally, so that a
different coupling mechanism needs to be found. As for the first pairing
mechanism, Ruhman and Lee maintain the view expressed in their paper (Ruhman
and Lee, Phys. Rev. B 94, 224515 (2016)) that the energy range over which the
usual longitudinal optical phonon mediated interaction operates is limited by
the Fermi energy. We object to this view and in this reply present evidence
that the cutoff energy is much larger. In a weak coupling system such as
SrTiO$_{3}$ the cutoff is given by the energy beyond which quasiparticles cease
to be well defined.
