Scientists agree that the universe was in a hot, dense period approximately 13.8 billion years ago. Everything we have observed, from the Cosmic Microwave Background (CMB) to the expansion of the universe to the distribution of light elements, supports this hypothesis. The Big Bang was one of the most spectacular discoveries of the 20th century, blindsiding many scientists who had concluded that the universe was static and eternal.

Its original formulation, however, used Einstein’s theory to show that if the universe is of equal density everywhere and has no biases in any particular direction, then—from its expansion—we can work backward to an infinitely dense singularity from which all matter and energy emerged.

This idea quickly runs into problems, however. The CMB is too highly correlated with itself. The universe is also remarkably flat spatially. What explains this flatness?

Inflationary theory was developed to explain these problems. The idea is that the universe before it was full of matter and radiation was full of inflationary energy. This energy caused it to inflate until some point, when that energy spontaneously converted into matter and radiation, leading to the structures we see in the universe today.

This idea led to the idea of Eternal Inflation, where we exist within a vast multiverse where universes pop into existence all the time from false vacuum (energy states that are higher than true vacuum, which is nothingness).

It is incorrect to assume that Eternal Inflation eliminates the need for a prime mover to create the universe because it is eternal and, therefore, does not need a cause. Its own creator says it must have a beginning.

The idea of eternal inflation raises several problems, and various solutions are being considered, but what I want to talk about in this post is whether Eternal Inflation or other Multiverse ideas are better ideas than that of an uncaused intelligent being—”God”, if you will—creating the universe.

I’ll first start from the Kalam Cosmological Argument, a product of Islamic medieval scholasticism and one of the best arguments for the need for a cause to the universe, which, stated very simply, is this:

1. Whatever begins to exist has a cause of its beginning.
2. The universe began to exist.
3. Therefore, the universe has a cause of its beginning.

#1 is sometimes incorrectly written as “Everything has a cause,” but it is carefully worded to accord those things with a cause to those things that have a beginning. If something does not have a beginning, therefore, it does not need a cause. Note that even subatomic particles, which “pop” into existence in particle accelerators, have a cause, i.e., the matter and energy from which they emerge.

An atheist would not dispute this syllogism, nor would a theist. The difference between them would be in how to resolve the cause. Atheists tend to go in two directions here (usually both at once):

1. An eternal multiverse is a reasonable cause to the universe.
2. We don’t know what caused the universe to begin. Therefore, it is unreasonable to come to any conclusion.

#2 unfortunately ignores philosophical arguments completely, which are necessary to form any reasonable understanding of the universe. Consider that concepts like rationality, logic, and the existence of science itself, i.e., that evidence can tell us something about the universe, are philosophical, not scientific. You must adopt some kind of framework on faith because you cannot prove it with evidence (otherwise, you’d be assuming what you are trying to prove). Saying that science just “works” is a cop-out. At best, you could argue that rationality is an illusion that has been useful to us in our evolutionary process, but again, why would you trust your brain if rational thought is an illusion? Why bother reading this article if you don’t believe in logic? Isn’t it all just words? If you believe this, read no further.

Despite the lack of scientific evidence for a Creator or other universes, we must accept philosophy as another kind of evidence and plow ahead.

I am going to use the word “Creator” here instead of God to avoid the connection to the God of the Bible. A completely different set of premises and facts would be needed to make that argument.

First, even if we accept the cosmological argument that the universe needs a cause, why does that cause need to be uncaused, as I’m asserting from the get-go? One can argue that perhaps whatever caused the universe also has a beginning, but if you do that, you simply move the cause backward. You don’t resolve anything.

For example, suppose the universe is the result of natural selection as in the Cosmological Natural Selection (CNS) theory, on which I have written many times. In this theory, Big Bangs are born out of black holes in mother universes. Disregarding what the actual pressures for natural selection are in this case, one can assume that in an ecosystem where the universe emerges from a natural selection process, there could be billions or trillions of universes preceding ours. 

I argue, however, that there has to be a first universe in this process. It cannot proceed indefinitely for an infinite regress. 

Infinite regresses can lead to absurd conclusions.

David Hilbert, the great early 20th-century mathematician and my great-great-great grand advisor (along with tens of thousands of other mathematicians living today), came up with the idea for the Hilbert Hotel to demonstrate how infinities work qualitatively differently from finite numbers.

The Hilbert Hotel has infinite rooms numbered 1, 2, 3, and so on forever. Suppose all the rooms are full. The Hotel is infinitely occupied. Now, a guest arrives. Should the Hotel Manager turn them away?

Not at all!

The manager simply asks each guest to move to the next room over, so the guest in 1 moves to room 2, and the guest in room 2 moves to 3. Since there are infinite rooms, this is always possible.

Thus, there is room for one more, always.

Likewise, if we have an infinite number of universes all generating one another or an infinite number of universes coexisting in some other way, we have the same possibility.

Now, some have argued that this is no big deal. Perhaps you can have an infinite number of things but situations like Hilbert’s Hotel are impossible, for example. Or perhaps they are possible, and the apparent absurdity is just a quirk of our finite human minds.

In the case of natural selection, however, it does create a problem because we have an infinite causal chain of universes where at least some information is passed on from one universe to the next.

This means that information comes from “nothing” because it always exists infinitely backward in time. The information is an uncaused cause. 

This runs into another apparent paradox called the bootstrap paradox.

Suppose I am a time traveler. I take the score for Beethoven’s 5th symphony, travel back in time, and give it to Beethoven before he ever wrote it. He then publishes that symphony as his own.

Where did the symphony come from? Who wrote it?

No one.

The same is true with an infinite regress of universes. It contains information that has no cause.

Perhaps this is how information works, but then one must accept the bootstrap paradox as well. Information ex nihilo.

The same is true if the universes are finite in number but form some kind of cyclical causal structure, of course.

Thus, in the case of CNS, we need a first universe, so infinite regress is not possible, just as life needs a first living thing to start evolution.

In the case of other multiverse ideas like Eternal Inflation, this is not necessarily an issue because the multiverse itself is entirely random noise. Our universe only appears to contain causal information because we happen to live in it. It is random. In CNS alone, none of the universes are random. When asked who authored the information that created the universe, the genuine answer is “no one.” This is more like if I just generated an infinite number of musical scores. One of them would be Beethoven’s 5th Symphony.

A multiverse of random universes need not have an infinite number of universes. It need only be indefinitely large, i.e., whatever makes our universe likely to appear, no matter how big that number is. The Eternal Inflation multiverse, however, has to be “eternal,” meaning it is effectively infinite and uncaused.

This creates another problem because if you have an infinite amount of time stretching backward into the past, how could the present ever have been reached?

If time proceeds linearly, one event causing another in an infinite chain of events, then no event can ever be said to have occurred since it would take an infinite amount of time and causal events to reach that event.

How could anything happen?

If this is too hard to wrap your mind around, let’s take a concrete example. Suppose some event in the past, World War 2, for example, instead of lasting about 6 years, lasted for an infinite number of years? How could we be living after that event? Surely, we would never reach the present if events took infinitely long to unfold.

Another problem with infinite time is called the Grim Reaper Paradox, which itself has a variety of solutions but essentially says that there are an infinite number of Grim Reapers who will kill a person by a certain time if another Grim Reaper hasn’t already done it. You can see the issue here. Since there are an infinite number of them, one in the past surely would have done it, but because there is an infinite number, none can have done it.

Alan Guth, cocreator of the Eternal Inflation theory, admits this is a problem and simply writes:

“The question of whether the universe had a beginning is discussed but not definitively answered. It appears likely, however, that eternally inflating universes do require a beginning. Thus, we are stuck with needing a cause after all for Eternal Inflation to make sense.”

There are other problems with infinite multiverses, even if they do not have a shared time coordinate, such as the measure problem. Essentially, if you have an infinite number of universes like ours, you also have an infinite number of universes that contain absurdities. Guth, in an interview with Quanta Magazine about this problem, is quoted as saying: “In a single universe, cows born with two heads are rarer than cows born with one head.” But in an infinitely branching multiverse, “there are an infinite number of one-headed cows and an infinite number of two-headed cows. What happens to the ratio?”

How do you, therefore, get away with the argument that ours is the most likely universe in which we ought to appear? For example, why do we appear to live in a very old universe when Eternal Inflation predicts most universes are very, very young (Youngness Problem)? And why aren’t we just Boltzmann Brains, flashing into existence with our minds filled with fake information? How do we rule that out?

These may seem like scientific hypotheses that simply need to be tested, but they are strong philosophical arguments against Eternal Inflation, and when philosophy is the only evidence you have, you’d better pay attention to it. Just like observational evidence, philosophical evidence must be weighed to determine the strength of an argument. We aren’t looking to support the truth with absolute certainty here but to find the best argument we can.

One solution is to look only at universes that are causally connected within the multiverse, known as the stationary measure. This provides some constraint on which universes we ought to look at instead of focusing on the entire absurdly infinite multiverse. It isn’t clear this idea solves the problem, however. It simply tries to reduce the infinities to something more manageable but doesn’t extricate itself from the problems in any definitive way. How do you define causal connection? (E.g., maybe this means some kind of CNS multiverse existing within the larger Inflationary ecosystem.)

If you go ahead and do this, you run into other problems, such as how do you deal with infinite causal regress, and if you have only finite causal connections, then what is the first cause? Is it just ex nihilo? Random?

Given the problems with infinite regress, we have to go back to the cosmological argument: something that is itself uncaused caused the universe or some causal predecessor of the universe to begin.

If that isn’t an infinite chain of cause and effect, then it must be some kind of Creator capable of imparting information to the universe.

The argument that this Creator is a personal being with free will comes from the observation that anything that begins to exist at a finite time (or sequence of causal events) in the past implies something that has the power to choose to begin it. Otherwise, we would expect the universe to exist side-by-side with its uncaused cause eternally.

Observe that in our universes, causes and effects tend to exist side-by-side. Effects begin at a particular time because their causes begin at a particular time. Those effects cease when the conditions that caused them cease. Water melts when the temperature is above freezing and freezes when it drops below. The cause of the temperature is a mixture of solar radiation and other random weather conditions. The cause of that is the formation of our planet and the Solar system, the state of the Earth in its orbit, and so on.

You can work your way back in time to determine why any effect happened.

In the case of quantum mechanics, this cause may be random, but the quantum wave function itself is deterministic, and it imparts random causes and effects based on other causes and effects.

Yet, in the case of an uncaused cause, it has nothing to work back towards.

Thus, we have two options to explain philosophically why the universe began at a finite time in the past:

1. The uncaused cause creates randomly like the Eternal Inflation universe.
2. The uncaused cause creates based on free will.

In the case of a random creator, we are forced to infinities again because otherwise, we’d have to give a cause for why the random creator just chose to start creating randomly. The random creator had to have been creating infinitely to create a universe as complex, life-supporting, and finely tuned as ours.

In the case of free will, we are faced with a timeless and eternal Creator who chose to create a Personal Creator, i.e., one that is a Person. This is true even in the CNS multiverse.

The argument that a Personal Creator is a cop-out, a bad and unscientific explanation for existence, falls apart based on all these arguments above. Indeed, such arguments tend to be circular because they want to hold up naturalism, the idea that all causes must be “natural” and that a Personal Creator is a supernatural phenomenon that cannot explain anything, as an axiom. Yet, there is nothing unnatural about a Personal Creator. We, after all, are persons, and we are natural. Just because we evolved brains that endow us with reasoning power does not mean that all persons must be the product of a blind process. This hidden assumption that a person must have a cause is unfounded.

Nor is it sensible to try to read back into the Personal Creator concept a Judeo-Christian understanding of God in an attempt to disprove it. One can only argue, from cosmological reasons alone, to quote philosopher William Lane Craig, that the universe or multiverse has a “beginningless, uncaused, timeless, spaceless, changeless, immaterial, enormously powerful, Personal Creator.” There is no mention of goodness, so arguments from evil are not appropriate here.

At best, one can try to plug holes in a leaky boat of philosophical arguments for why this universe is the one we find ourselves in, bending over backward to try to avoid a Personal Creator or try to deny there is a problem at all. But the latter is increasingly becoming a fringe theory in both physics and philosophy. We agree there is a problem. So far, no one has come up with a convincing alternative to a Personal Creator as the cause of it all.

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