  Given the fact that Earth is so far the only place in the Milky Way galaxy
known to harbor life, the question arises of whether the solar system is in any
way special. To address this question, I compare the solar system to the many
recently discovered exoplanetary systems. I identify two main features that
appear to distinguish the solar system from the majority of other systems: (i)
the lack of super-Earths, (ii) the absence of close-in planets. I examine
models for the formation of super-Earths, as well as models for the evolution
of asteroid belts, the rate of asteroid impacts on Earth, and of snow lines,
all of which may have some implications for the emergence and evolution of life
on a terrestrial planet.
  Finally, I revisit an argument by Brandon Carter on the rarity of intelligent
civilizations, and I review a few of the criticisms of this argument.
