Multiverse Predictions for Habitability: Fraction of Life that Develops
  Intelligence
  Do mass extinctions affect the development of intelligence? If so, we may
expect to be in a universe that is exceptionally placid. We consider the
effects of impacts, supervolcanoes, global glaciations, and nearby gamma ray
bursts, and how their rates depend on fundamental constants. It is interesting
that despite the very disparate nature of these processes, each occurs on
timescales of 100 Myr-Gyr. We argue that this is due to a selection effect that
favors both tranquil locales within our universe, as well as tranquil
universes. Taking gamma ray bursts to be the sole driver of mass extinctions is
disfavored in multiverse scenarios, as the rate is much lower for different
values of the fundamental constants. In contrast, geological causes of
extinction are very compatible with the multiverse. Various frameworks for the
effects of extinctions are investigated, and the intermediate disturbance
hypothesis is found to be most compatible with the multiverse.
