  It is possible that the scale of gravity, parameterized by the apparent
Planck mass, may obtain different values within different universes in an
encompassing multiverse. We investigate the range over which the Planck mass
may scan while still satisfying anthropic constraints. The window for
anthropically allowed values of the Planck mass may have important consequences
for landscape predictions. For example, if the likelihood to observe some value
of the Planck mass is weighted by the inflationary expansion factors of the
universes that contain that value, then it appears extremely unlikely to
observe the value of the Planck mass that is measured within our universe. This
is another example of the runaway inflation problem discussed in recent
literature. We also show that the window for the Planck mass significantly
weakens the anthropic constraint upon the cosmological constant when both are
allowed to vary over a landscape.
