The Hidden Reality: Parallel Universes and the Deep Laws of the Cosmos

by Brian Greene

But the earth is not the only planet in the universe, let alone in the solar system. There are many others. And this fact casts such questions in a very different light. To see what I mean, imagine that you mistakenly think a particular shop carries only a single shoe size, and so are gleefully surprised when the salesman brings you a pair that fits perfectly. “Of all possible shoe sizes,” you reflect, “it’s amazing that the single one they carry is mine. Is that just a lucky coincidence? Is there a deeper explanation?” But when you learn that the shop actually carries a wide range of sizes, the questions evaporate. A universe with many planets, situated at a range of distances from their host stars, provides a similar situation. Just as it’s no big surprise that among all the shoes in the shop there’s at least one pair that fits, so it’s no big surprise that among all the planets in all the solar systems in all the galaxies there’s at least one at the right distance from its host star to yield a climate conducive to our form of life. And it’s on one of those planets, of course, that we live. We simply couldn’t evolve or survive on the others.

Wow. The obtusness here is impressive. The fact that the earth is the only place where life of any kind has been observed makes this whole defense moot at this point and completely validates the original question, based on current evidence. (And to base an objection on the possibility of future evidence is an exercise in faith, not reason.)