Wednesday, July 31, 2013

Even in the multiverse, our universe is rare

Last time I ended with the cliffhanger, saying the multiverse (the idea there are a vast number of other universes out there) strengthens the design argument for God.  This discussion stems from the widespread realization, from scientific data, that our universe appears "designed".  The constants of physics and structure of the universe are finely-tuned: they must be just-right in order for life to exist.  Even non-theistic scientists acknowledge this.  (See here for a great website that has compiled many quotes to this effect.)  However, what if there are an infinite number of universes, each with their own random laws of physics?  By sheer numbers then, we should expect at least one bio-friendly universe to exist.

And the fact that we exist says that such a universe exists.

This last point is incredibly important.  It is called a "selection effect".  Even though it's rare that a bio-friendly universe exists, the idea is that it is not rare for observers to note they live in a bio-friendly universe.  The very fact that observers exist (and are living) shows they must be in such a universe.

But here's where it gets weird.  It turns out that, of all possible universes with observers, our universe is still rare.  Because of the extreme degree of fine-tuning necessary to make this universe bio-friendly, it is actually far more probable that a universe composed simply of a star and a host of planets (including the life-friendly one) just popped into existence (POOF!) out of the quantum vacuum.  I repeat: it is far, far more probable that an entire life-friendly solar system just popped into existence with no explanation.

It gets weirder.  Considering those types of universes are more probable, and that presumably in some of those universes, life will have evolved to the point of being technologically advanced, it's actually more probable that we are just in a Matrix-like computer simulation from these advanced life-forms.  In that manner, we'd be "intelligently designed" (but also our world would not be "real").

It gets weirder.  Even more probable than the solar-system-out-of-nothing scenario, by far the most common type of universe with an observer(s) is one in which a single brain pops into existence, looks around and notes the nothingness in which it sits, and then pops out of existence.  (This is called the "Boltzmann Brain".)

All of these then beg the question: why do we live in a universe that is so extremely finely-tuned (to such a degree that it is prohibitively rare, even in a multiverse), when it's far more likely that we wouldn't live in such a universe?  The clear-cut answer is that our universe did not arise by chance.  We are not just a lucky accident of the quantum vacuum churning out random universes.  Our universe was supernaturally designed by the One who has the power and care to undertake such a creative event.