One of the major discoveries of cosmology over the past century is that the physical constants of our universe all exist within an extremely narrow range, such that to change any one to an infinitesimal degree would result in a physics in which no life would be possible. There appears to be no law of logic dictating that the constants be such as they are, hence things could have been different, and thus this unfathomably unlikely state of affairs requires an explanation, with the only one that seems to make sense being that the laws and constants of physics were designed intentionally by an intelligent Creator for the purposes of making life possible.

Additionally, even given the physical laws and constants necessary for life that our universe has, planets possessing all the conditions necessary for habitability and materials necessary for advanced life appear to be exceedingly rare. Our Earth may be the only one.

And even given a habitable planet, every bit of evidence we have tells us that s chance origin of life is either physically impossible or so radically improbable that it may as well be. The remoteness of the probability here is so extreme that it cannot be expressed in numbers that are comprehensible to us, and time is of no help here because chemistry actively destroys all of the major ingredients that would be needed.

And finally, even given the origin of life, there is no law of logic dictating that microbes have to evolve into anything other than microbes, much less into conscious, rational creatures like us who are capable of grasping abstract concepts like numbers and discovering the cosmological constants and the chemical makeup of life and realizing how fantastically improbable it all is. This again, I would (and will) argue is impossible to happen naturalistically, but even granting naturalistic assumptions, it’s at least radically improbable.

Enter the Multiverse

Now, the straightforward, commonsense conclusion to draw from these extreme improbabilities on top of extreme improbabilities on top of even more extreme probabilities is that none of these things are this way by chance at all, but that they have all been intentionally orchestrated this way by a Mind who transcends this physical and contingent universe, for the purposes of making rational creatures like ourselves.

Now, if you’re an atheist for whom this conclusion is unacceptable, you have quite limited options for alternatives, really only two.

The first is to deny that any of these things are real and in need of explanation. An atheist who took this route would say that human beings are not objectively real, that life is not objectively real, and thus that cosmological constants and planetary constraints necessary to support life and human beings are not objectively real nor in need of explanation. Rather, such an atheist would say, all these things are subjective constructs or illusions that we project. I won’t address the obvious self-defeating irrationality of this view here, but I touched on it in towards the end of the introductory article to this series.

Atheists who don't want to abandon logic and science altogether, then, really have only one option: They have to attribute all of the above to chance, and given the unfathomably extreme improbabilities involved, they need an unfathomably extreme amount of chance to do it.

This is where multiverse theories come in. These are theories to the effect that there are an infinite, or practically infinite, number of universes besides the one we live in, such that every possible combination of physical laws, constants, and improbable events plays out somewhere, indeed in an infinite (or practically infinite) number of somewheres.

The multiverse proponent’s explanation for the vast improbabilities that we observe to be necessary for out existence, then, is this: Given that there are infinite universes, every possible thing that can happen will happen no matter how improbable, including the extremely improbable combination of events necessary to make rational conscious observers such as ourselves to exist. And because rational conscious observers like ourselves will only exist in universes in which the unfathomably unlikely combination of events necessary to cause their existence occurred, rational conscious observers who become advanced enough to study the circumstances of their own existence will always observe that the combination of physical laws, constants, and series of events necessary for them to exist are unfathomably improbable.

Now, there have been a proliferation of such multiverse theories in recent decades under different pretexts, the details of which I will not attempt to go into, but all of them are motivated by the desire to explain away observes improbabilities that would otherwise require an appeal to God via the same argument just given.

There have also been many valid criticisms of these sorts of theories, from both theists and non-theists, pointing out that they are purely ad-hoc, that they are examples of special pleading, that they are unfalsifiable in principle, that they are exercises in purely motivated reasoning, that they are unparsimonious and violate Occam's razor (indeed, they are as ANTI-parsimonious as it is possible to be, as they seek to explain things by multiplying unnecessary and unobserved entities to literal infinity), and that they don't actually explain anything because now we must account for why there is an infinite multiverse that does just what the atheist needs it to do instead of just one universe.

However, as valid as these criticisms are, there is a more serious and fundamental problem than all of these with the whole multiverse concept: It is self-defeating. All multiverse theories are logically incoherent UNLESS they appeal to the very transcendent designing Mind to explain the existence of rational observers that they are meant to explain away. Again, they are not merely unconvincing or ad-hoc, but logically incoherent.

Infinite Chance: The Anti-Explanation

Here’s the problem: If you can appeal to unlimited chance resources as multiverse theories do, you could use them to explain ANY observable phenomena away. For instance, you might argue that gravity doesn't actually exist, but rather that matter has just happened to move by pure chance AS IF gravity existed whenever we've happened to be looking. Or you might argue that the universe, along with yourself and your false memories of learning about gravity all came into existence by chance 5 seconds ago. These things are absurd, but given infinite universes in which every possible combination of things happens, it would have to happen somewhere - indeed, an infinite/unlimited number of somewheres! To apply this mode of chance “explanation” consistently across the board would be fatal to the entire concept of causality, to all scientific explanation, and indeed to all rational inquiry and thought.

Thus, implicitly, there has to be some non-arbitrary basis by which the infinite chance argument ONLY applies to improbable things that the multiverse proponent wants to explain away and nothing else, otherwise it collapses in on itself logically.

The Cure That’s Worse Than The Disease

Now, those who invoke the multiverse idea as a fine-tuning defeater implicitly have such a basis in mind: the existence of conscious rational observers. As we already saw above, the underlying argument is that only those causes that were necessary to bring about the origin of conscious rational observers (namely ourselves) can be accounted for by the unlimited chance resources of a multiverse, because only in those universes where those causes occur will conscious rational observers exist who will be able to consciously observe the laws and constants of physics and to rationally deduce that the causes of their existence are fine-tuned and improbable.

But to make this argument means that you must be able to make an objectively real, ontological distinction between causes that brought about conscious rational observers and those that didn't, such that only the former can be explained away by chance.

And to make THAT distinction entails an objectively real, ontological distinction between conscious rational observers themselves and everything else in the universe, such that the category of conscious rational observer is irreducible to anything else in the universe and is thus a substance in the Aristotelean sense. Recall from Principle #3 in the initial article in this series that the objective existence of something entails its irreducibility.

And that means, via Principle #2 (aka the Principle of Sufficient Reason), that the existence of conscious rational observers as irreducible substances can only be accounted for if the "multiverse" either possesses or is itself caused by something (or rather Someone) possessing the powers of conscious rational observers, from which we conscious rational observers are causally derived.

Coming Full Circle

But at that point you are affirming the existence of a transcendent Mind, aka God, as the grounds for our existence, which renders appeals to multiverses and unlimited chance resources entirely superfluous for their intended purpose of explaining away God. The multiverse proponent is left with an infinite number of unnecessary and unobservable hypothetical entities postulated for no reason whatsoever, just to get back to where he started, rendering the whole thing a completely pointless exercise in a badly overused sci-fi trope.

Multiverse theories thus shoddy thinking at its worst. They invent an infinite number of hypothetical entities for which there is zero evidential basis, all to explain nothing and to entail the very Creator God and rejection of materialism that they were conjured up to avoid.