I wrote this review on Goodreads.com last year, and I felt like posting it here now:
Atoms (and other particles/waves/fields) bounce against each other everywhere in this universe.
If they started out from random places, there would be no way to tell if a description of their motion is being narrated in reverse. (Analogy: If a game of pool was watched in reverse you cannot tell if the game is watched in reverse if the game had no beginning)
Atoms don’t start out moving from random places. They start their motion from some places more than others e.g. centers of stars. Because of this, it is easy to tell whether their motion is being described in reverse. Just look at the part of the narrative where they were in fewer places; that is where they “began” moving from. The rest of the description happened “afterward”.
If we apply the entire argument to the universe, we can guess (and verify), that all of the stuff around us started moving from somewhere.
But what put all of the universe in fewer places instead of being scattered everywhere as it naturally should be? It is much more likely for stuff to be scattered everywhere than to be forced to be somewhere.
We can’t say an intelligent designer (e.g. god) did it because a god is purported to be something too, and much like the universe bound by the same argument above. It is even more unlikely for god(s) to just miraculously be in the formless and the void.
We can’t say universe just happens from time to time because then tiny little brains with awareness would be easier to form than the entire universe with billions of brains in them. And we would find ourselves to be one of those tiny little brains without the world to be in.
Sean Carroll concludes the book by guessing that a universe like ours happens from time to time. But by his own argument, that would mean tiny little brains in the void (not god) are more likely than the entire universe with billions of tiny little brains in them. By his argument, we ought to have found ourselves to be similar to Tolkien’s Ainur than as Men.
Anyways he thinks not only does universe happen from time to time, but the said universes also either move towards greater order or greater disorder.
I feel we are missing out something crucial in these grand narratives. I can’t say what, but a lot of things which seem to be random at the macroscopic scale isn’t so random in microscopic scale e.g prime numbers – they are random when studied statistically, but they can be generated by a deterministic process.
BTW there is nothing stopping tiny little brains inside improbable universes figuring out ways to make even more improbable universes with more tiny little brains in them. We just need to figure out how.