Multiverse Predictions for Habitability: The Number of Stars and their
  Properties
  In a multiverse setting, we expect to be situated in a universe that is
exceptionally good at producing life. Though the conditions for what life needs
to arise and thrive are currently unknown, many will be tested in the coming
decades. Here we investigate several different habitability criteria, and their
influence on multiverse expectations: Does complex life need photosynthesis? Is
there a minimum timescale necessary for development? Can life arise on tidally
locked planets? Are convective stars habitable? Variously adopting different
stances on each of these criteria can alter whether our observed values of the
fine structure constant, the electron to proton mass ratio, and the strength of
gravity are typical to high significance. This serves as a way of generating
predictions for the requirements of life that can be tested with future
observations, any of which could falsify the multiverse scenario.
