Many people have put forward this argument; for my money the most lucid is Paul Davies' The Goldilocks Enigma.
Its subtitle is "Why is the Universe just right for Life?" I confess it seems to me that he inhabits a very different universe - the universe I see around me seems almost implacably hostile to life, and we exist on the razor's edge of that "almost". Only one world in the whole of Creation - and on that world 99% of all species that ever lived are extinct?! As if Goldilocks had found the one bowl of soup in an ocean of poison...
I am intrigued - what do you think?
On the specific issue of the "fine tuned" fundamental constants, I'll be blunt - I think its a total crock. There is zero evidence that these constants are tunable in the first place, any more than the value of pi was finely tuned so that billiard balls could be round. With a better fundamental theory, we should be able to calculate their values from first principles, just as we calculate the value if pi.
After all, a century ago, organic chemistry was cited as evidence how "finely tuned" the carbon-carbon bond was - else life could not exist. Tuned by God, one might argue. But today we can simply calculate the properties of the carbon-carbon bond using simple quantum mechanics (I remember actually doing this in 10th grade), and hence show it could not have been other than it is.
And if there is nothing to tune, that rather pulls the rug out from under the supposed tuner.
What did you use? Hartree-Fock, perturbation theory, CI, density functional theory, or...?
Cheers!
You're entering some deep philosophical waters, here.
The problem is, we don't have enough physical data to determine which of the various flavors of string theory / supersymmetry / turtles all the way down is the "true" one: and then there is the controversy over Everett's "many worlds" interpretation of quantum mechanics: which I understand even Everett's PhD advisor, John Wheeler, later rejected.
Without the knowledge of whether there "could have been" (whatever that means!) more than one "universe" we don't know if the values "could" vary.
And if there is only one universe, we then don't know for sure why the constants "have" the values they possess.
As to your Goldilocks analogy, you are missing an important point -- if there were lots of inhabited worlds that would be taken by the skeptic as confirmation that life arose surely by natural processes, without need for the awkward invention of a creator: but if there is only one inhabited world, with most species extinct, that is taken as evidence that a creator wouldn't be so clumsy and inefficient, and have a more hospitable universe.
The fallacy in the argument is that we have no knowledge a priori for deciding what a creator is like, and no way we can guarantee will be efficacious for testing said theories.
So any models of theism end up being as crude as the joke of the physicist modeling a thoroughbred as a spherical horse.
And of course it is unsatisfying, not tidy, and generally in poor form to retreat from experimental empiricism when investigating theories of a putative divine being or beings, especially when such methods have proved so, well, fruitful, in all other endeavors.
One thing which may help to resolve this is the realization that if there *is* a creator, they may take umbrage at being poked, modeled, experimented on and so forth, by a mere creature: just imagine how much a tenured professor of clinical psychology would be pissed off upon finding out that his lab mice were in cahoots to investigate and explain HIM.
Then exponentiate it, since the prof did not create the mice, directly or indirectly.
And before taking the obvious answer, recall that Hitchhiker's Guide and its sequels were FICTION.
Cheers!