The Multiverse

1 Introduction

During a discussion on myths that pre-date Jesus, an apologist introduces the concept of the multiverse. It’s not clear but I think he is claiming that the concept of multiple universes is an invention by atheists as a way to explain fine-tuning, without requiring the God hypothesis. This is wrong for at least four reasons:

• The multiverse is not a new idea
• The multiverse concept is inherent in many religions
• Multiple universes are found to be inherent in the theoretical physics of our universe in multiple theories
• The multiverse does not counter God-based creation (He could have created the multiverse).

1.1  Etymology

The concept of multiple universes is not new, but the word “multiverse” is fairly new, having been coined by American psychologist William James in 1895:

“But those times are past; and we of the nineteenth century, with our evolutionary theories and our mechanical philosophies, already know nature too impartially and too well to worship unreservedly any god of whose character she can be an adequate expression. Truly all we know of good and beauty proceeds from nature, but none the less so all we know of evil. Visible nature is all plasticity and indifference, a moral multiverse, as one might call it, and not a moral universe.”

2 The Multiverse in Ancient History

2.1 The Ancient Greeks

Atomism  originated in Ancient Greece about 2500 years ago. Several atomists at that time proposed multiple universes. For example, Democritus:
“In some worlds there is no Sun and Moon, in others they are larger than in our world, and in others more numerous. In some parts there are more worlds, in others fewer; in some parts they are arising, in others failing. There are some worlds devoid of living creatures or plants or any moisture.

2.2 Hinduism

The Hindu Puranas contain several references:

Every universe is covered by seven layers--earth, water, fire, air, sky, the total energy and false ego—each ten times greater than the previous one. There are innumerable universes besides this one, and although they are unlimitedly large, they move about like atoms in You. Therefore You are called unlimited [ananta].

Lord Siva said: My dear son, I, Lord Brahma and the other demigods, who rotate within this universe under the misconception of our greatness, cannot exhibit any power to compete with the Supreme Personality of Godhead, for innumerable universes and their inhabitants come into existence and are annihilated by the simple direction of the Lord

After separating the different universes, the gigantic universal form of the Lord [Maha-Visnu], which came out of the causal ocean, the place of appearance for the first purusa-avatara, entered into each of the separate universes, desiring to lie on the created transcendental water [Garbhodaka].

2.3 Buddhism

"Disciples," the Buddha said "nowhere between the lowest of hells below and the highest heaven above, nowhere in all the infinite worlds that stretch right and left, is there the equal, much less the superior, of a Buddha. Incalculable is the excellence which springs from obeying the Precepts and from other virtuous conduct."

Jataka Tales of the Buddha Part I

2.4 Islam

Imam Fakhr al-Din al-Razi was one of the outstanding figures in Islamic theology. Hedescribes the main arguments against the existence of multiple worlds or universes, pointing out their weaknesses and refuting them. This rejection arose from his affirmation of atomism, as advocated by the Ash'ari school of Islamic theology, which entails the existence of vacant space in which the atoms move, combine and separate. He argued that there exists an infinite outer space beyond the known world, and that God has the power to fill the vacuum with an infinite number of universes.

2.5 Christianity

There are many Christians who recognise that the concept of a multiverse does not conflict with belief in God and examples are provided in section 4. It is worth noting here that in common with most religions, the Bible refers to other universes, for example:

You, however, are not in the realm of the flesh but are in the realm of the Spirit, if indeed the Spirit of God lives in you
- Romans 8:9

From deep in the realm of the dead I called for help, and you listened to my cry.
- Jonah 2.2

For in the realm of the dead, where you are going, there is neither working nor planning
- Ecclesiastes 9:10

Jesus answered, "My kingdom is not of this world. If My kingdom were of this world, then My servants would be fighting so that I would not be handed over to the Jews; but as it is, My kingdom is not of this realm."
- John18:36

Here is one Christian's views of spiritual realms...

The spiritual realm is as real as the natural realm. In fact the spiritual realm determines what takes places in the natural realm. God has blessed us in the heavenly realms with every spiritual blessing in Christ. When Jesus died and rose again He appeared to his disciples and then ascended up into heaven (Acts1:9-11).  Although the location of heaven is up high above the earth, its operation is all over the earth and in our hearts. The spiritual realm is a real world, invisible to the natural eye but visible to the eye of faith.

3 The Multiverse in Modern Times

3.1 Modal Realism

The philosopher David Lewis developed the philosophy of Modal Realismin the 1960s and this is perhaps the most extreme multiverse idea. To summarise: All possible worlds are as real as the world we experience.

In physics, the multiverse appears in the solutions to the three main aspects of the physics of our universe: Quantum Mechanics (which describes the behaviour of particles), cosmology (which describes the nature of space-time) and string theory (which describes the nature of particles).

3.2 Quantum Mechanics

The many-worlds hypothesis came from Hugh Everett in 1957, as an interpretation of quantum mechanics alongside the Copenhagen interpretation and pilot-wave theory.  With each quantum event (occurring everywhere, every second), the world splits into many worlds, one for each possible outcome. Each of these worlds is at that time identical, except for the one different outcome. Thereafter, they develop independently, continually splitting as more quantum events occur.

 

For example, there are numerous copies of myself, in other worlds, that have split off from me since my conception. Since no communication is possible between the various worlds, each copy of myself believes he is the real me.

3.3 Inflation

The Big Bang model shows that when the universe grew exponentially in the first tiny fraction of a second after the Big Bang, some parts of space-time expanded more quickly than others. This could have created "bubbles" of space-time that then developed into other universes. Our universe has its laws of physics, while other universes could have different laws.

Alan Guth of MIT explains: "It's hard to build models of inflation that don't lead to a multiverse, but it's not impossible, so I think there's still certainly research that needs to be done. But most models of inflation do lead to a multiverse, and evidence for inflation will be pushing us in the direction of taking [the idea of a] multiverse seriously."

Other researchers agreed on the link between inflation and the multiverse. "In most of the models of inflation, if inflation is there, then the multiverse is there," Stanford University theoretical physicist Andrei Linde, who wasn't involved in the new study, said at the same news conference. "It's possible to invent models of inflation that do not allow [a] multiverse, but it's difficult. Every experiment that brings better credence to inflationary theory brings us much closer to hints that the multiverse is real."

When Guth and his colleagues thought up cosmic inflation more than 30 years ago, scientists thought it was untestable. Today, however, researchers are able to study light left over from the Big Bang called cosmic microwave background radiation (CMB).

3.4 String Theory

The mathematical basis of string theory requires the existence of ten dimensions (nine of space and one of time). We only perceive three space dimensions and one time dimension, so the other six space dimensions are hidden from us .

The mathematical outcome of this is that there are 10⁵⁰⁰ different ways that a 4D universe like ours can exist within a 10 dimensional framework. This implies at least 10⁵⁰⁰ possible universes with slightly different physics in each one. This collection of possible universes is often referred to as the “string landscape.”

There are three important outcomes of String Theory with regard to the multiverse:

• There are plenty of logically possible and mathematically consistent universes besides our own
• The string landscape is exactly the sort of thing we would expect to find if a multiverse existed.
• Proposed mechanisms for turning the possible universes of the landscape into actual, physical entities exist, for example, eternal inflation which predicts regions of space expanding indefinitely to produce “bubble universes” that would produce a member of the string landscape

3.5 Consequences of Multiverse versus Single Universe

Theoretical physicist and Nobel Prize winner Steven Weinberg makes the point that if the hypotheses described above are true (especially in 3.4) then there may be no stand-alone, self-contained explanation for the nature of our universe, as he explains...

"Inflation is naturally chaotic. Bubbles form in the expanding universe, each developing into a big or small bang, perhaps each with different values for what we usually call the constants of nature. The inhabitants (if any) of one bubble cannot observe other bubbles, so to them their bubble appears as the whole universe. The whole assembly of all these universes has come to be called the “multiverse.”

These bubbles may realize all the different solutions of the equations of string theory. If this is true, then the hope of finding a rational explanation for the precise values of quark masses and other constants of the standard model that we observe in our big bang is doomed, for their values would be an accident of the particular part of the multiverse in which we live. We would have to content ourselves with a crude anthropic explanation for some aspects of the universe we see: any beings like ourselves that are capable of studying the universe must be in a part of the universe in which the constants of nature allow the evolution of life and intelligence. Man may indeed be the measure of all things, though not quite in the sense intended by Protagoras.

So far, this anthropic speculation seems to provide the only explanation of the observed value of the dark energy. In the standard model and all other known quantum field theories, the dark energy is just a constant of nature. It could have any value. If we didn’t know any better we might expect the density of dark energy to be similar to the energy densities typical of elementary particle physics, such as the energy density in an atomic nucleus. But then the universe would have expanded so rapidly that no galaxies or stars or planets could have formed. For life to evolve, the dark energy could not be much larger than the value we observe, and there is no reason for it to be any smaller.

Such crude anthropic explanations are not what we have hoped for in physics, but they may have to content us. Physical science has historically progressed not only by finding precise explanations of natural phenomena, but also by discovering what sorts of things can be precisely explained. These may be fewer than we had thought."

And...

"String theory, which predicts a multiverse, can’t be verified by detecting the other parts of the multiverse. But it might make other predictions that can be verified. For example, it may say that in all of the big bangs within the multiverse, certain things will always be true, and those things may be verifiable. It may say that certain symmetries will always be observed, or that they’ll always be broken according to a certain pattern that we can observe. If it made enough predictions like that, then we would say that string theory is correct. And if the theory predicted a multiverse, then we’d say that that’s correct too. You don’t have to verify every prediction to know that a theory is correct."

3.6 Evidence

The evidence for multiple/ universes depends on the hypothesis. But perhaps more significantly is the fact that multiple universes keep appearing unbidden as solutions to the equations in multiple areas of study (see above). It is important to keep in mind that the multiverse view is not actually a theory, it is rather a consequence of our current understanding of theoretical physics. This distinction is crucial. We have not waved our hands and said: “Let there be a multiverse”. Instead the idea that the universe is perhaps one of infinitely many is derived from current theories like quantum mechanics and string theory as described above.

But is there a way to test for multiple universes, in other words, are they falsifiable?  Well, the universes predicted by string theory and inflation live in the same physical space (unlike the many universes of quantum mechanics which live in a mathematical space), so they can overlap or collide. Indeed, they inevitably must collide, leaving possible signatures in the cosmic sky which we can try to search for.

The exact details of the signatures depends intimately on the models – ranging from cold or hot spots in the cosmic microwave background to anomalous voids in the distribution of galaxies. Nevertheless, since collisions with other universes must occur in a particular direction, a general expectation is that any signatures will break the uniformity of our observable universe.

These signatures can be tested by looking for imprints in the cosmic microwave background. There is also the evidence from gravitational waves which could be affected by the multiple dimensions predicted in string theory. There is even the possibility of building a particle accelerator with enough energy to create universes. The issue there is how would we detect them if we created them!

4 Modern Christian Approaches to the Multiverse.

Apologist objections to the multiverse ignore the possibility that the multiverse is part of God’s plan. There are Christians who earn a living as theoretical physicists and are able to reconcile the bizarre and counter-intuitive models of reality arising from quantum mechanics and string theory with their faith. Examples…

4.1 Evangelical cosmologist Don Page

Page offers a theological argument for the existence of the Many Worlds Interpretation:

“Science looks for the simplest hypotheses to explain observations. Starting with the simple assumption that {\em the actual world is the best possible world}, I sketch an {\it Optimal Argument for the Existence of God}, that the sufferings in our universe would not be consistent with its being alone the best possible world, but the total world could be the best possible if it includes an omnipotent, omniscient, omnibenevolent God who experiences great value in creating and knowing a universe with great mathematical elegance, even though such a universe has suffering.

God seems loathe to violate elegant laws of physics that He has chosen to use in His creation, such as Maxwell's equations for electromagnetism or Einstein's equations of general relativity for gravity within their classical domains of applicability, even if their violation could greatly reduce human suffering (e.g., from falls). If indeed God is similarly loathe to violate quantum unitarity (though such violations by judicious collapses of the wavefunction could greatly reduce human suffering by always choosing only favorable outcomes), the resulting unitary evolution would lead to an Everett multiverse of `many worlds', meaning many different quasiclassical histories beyond the quasiclassical history that each of us can observe over his or her lifetime. This is a theological argument for one reason why God might prefer to create a multiverse much broader than what one normally thinks of for a history of the universe.”

4.2 Physicist Tom Rudelius

Rudelius is a Ph.D candidate in Physics at Harvard and puts it like this…

“Beyond this, it should be noted that a multiverse is not in any way incompatible with Christian theism.¹⁶ Nowhere does the Bible suggest that God has created only one universe or one set of beings in his image. A successful multiverse scenario, at most, could help refute the teleological argument for God’s existence. But as atheistic philosopher Kai Nielsen pointed out, “To show that an argument is invalid or unsound is not to show that the conclusion of the argument is false…. All the proofs of God’s existence may fail, but it still may be the case that God exists.” God could perfectly well have created an infinite number of universes, even an infinite number of universes with intelligent life. After all, if you were God, would you really create just one?”

4.3 Theoretical physicist Michio Kaku 

Kaku explains how the science of the multiverse fits in to his religious upbringing…

“When speaking about the multiverse, I’m often asked questions about the different kinds of universes that can form as a result of extra dimensions, string theory or even chaotic inflation for example. These are in some sense different kinds of universes but for me personally, it’s very aesthetically pleasing. This all goes back to my childhood with my parents being Buddhist. In Buddhism, you believe in nirvana and timelessness with no beginning and no end. As a child I went to Sunday school where I learned about arks, great floods and the instant of creation when God said, “Let there be Light”.

So, all my life I’ve had these two competing paradigms in my head. With the multiverse idea, we have the beautiful melding of these two ideas. The reason being is that we do have this nirvana, this timelessness, this eleven dimensional hyperspace, this arena of string theory. But we also have bubbles that form all the time, almost like a bubble bath. Sometimes the bubbles expand rapidly giving us universes, combine with other bubbles and sometimes even pop. This continual creation, the idea of a multiverse is very pleasing to me because I can now meld Buddhist nirvana with Judeo-Christian epistemology.”

4.4 Mary-Jane Rubenstein

Rubenstein is Professor of Religion at Wesleyan University:

“If our world is the only world, then it's very difficult to explain: how is it that things are so perfect? How is it that sunsets are so beautiful? And the Atomists believed that it was not the case that some anthropomorphic god or gods made the universe so it was perfect, but that our world was one of an infinite number of other worlds. Worlds were the product of accident, of particles colliding with one another, and an infinite amount of space to play in.

Every major development in modern Western science since Copernicus has been advertised as this radical decentralization of our importance. Copernicus takes us out of the center of the solar system, and then Darwin takes us out of the garden of Eden, Freud takes us out of control of our own psyches — as science progresses, we learn that we are less and less important than we thought we were. But, of course, we still tend to think that we run the planet.

You do run into some fascinating theological problems. For example, if you are operating in a Christian framework, are there inhabitants of those other universes, and are they fallen? If they have fallen, do they also need Christ to go there and redeem them? Is Jesus just constantly traveling from universe to universe to get incarnated, teach for 30 years, and then die?”

4.5 William Lane Craig

The noted Apologist Craig says this in an interview:

Robert Lawrence Kuhn: Bill, does the idea of a multiverse—many different kinds of universes, enumerable universes—does that bother your theism?

Dr. Craig: No, it doesn’t bother my theism at all. I think that God as the infinite creator of all space and time could create separate space-time manifolds or create a universe so vast that there would be different causally unconnected domains within one universe. So, once you have an infinite transcendent creator, there’s simply no problem with the scope of the space-time world that he brings into being.

Robert Lawrence Kuhn: How about in quantum mechanics? As you know, there is something called branching or differentiation, where at every Planck time, as they say, there’s a branching of or differentiation of the worlds. There’s infinite numbers of us talking in different ways with very slight differences. And then you have a multiplicity of these quantum mechanical worlds.

Dr. Craig: That’s one way in which theorists have thought to generate a world ensemble of universes, though I think that most quantum physicists would regard this as an extraordinarily implausible interpretation of quantum mechanics.

Robert Lawrence Kuhn: My question for you is: Does that bother your theism, however you generate—

Dr. Craig: Oh no, no, it wouldn’t bother my theism at all because God would still be the one who established the laws of quantum mechanics, who created the quantum vacuum and the space and time, the arena in which all these reactions take place. So, as I say, once you have a transcendent source of all space and time, matter and energy, then he’s free to create any sort of physical reality he wants.

4.6 John Lennox

John Lennox is a mathematician and Christian Apologist. In this extract from his book "God's Undertaker: has science buried God?" he makes the point that God and a multiverse are not mutually exclusive and that the intelligent design argument can be applied to the multiverse just as it can to a single universe. He also makes a case that the existence of a multiverse provides a logical proof for the existence of God...

"It should be pointed out that although some suggest fine-tuning means either that there is a God or a multiverse, logically these two options are not mutually exclusive, although they are usually presented as such. After all, parallel universes could be the work of a Creator.  

Christian de Duve writes: ‘Even if the multiverse theory turns out to be correct, the deduction drawn from it by Rees and Weinberg strikes me as what is called in French ‘drowning the fish.’ Whether you use all the water in the oceans to drown the animal, it will still be there affirming its presence. However many universes one postulates, ours can never be rendered insignificant by the magnitude of this number... what appears to me as supremely significant is that a combination capable of giving rise to life and mind should exist at all.’ Therefore the multiverse argument does not in fact weaken the design arguments.

Another version of the multiverse theory, the many worlds interpretation of quantum mechanics, is that every logically possible universe exists. However, if every possible universe exists, then, according to philosopher Alvin Plantinga of Notre Dame University, there must be a universe in which God exists – since his existence is logically possible – even though highly improbable in the view of the New Atheists. It then follows that, since God is omnipotent, he must exist in every universe and hence there is only one universe, this universe, of which he is the Creator and Upholder."

4.7 Bernard Haisch

Bernard Haisch is a German-born American astrophysicist. In his book "The God Theory: Universes, Zero-point Fields, and What's Behind It All"  he makes the case for an underlying  intelligence, which we can refer to as God, to be the origin of the multiverse...

This implicitly assumes that some kinds of laws or fields preexist to allow quantum fluctuations to arise. No laws, no action. And of course this also implies that these universes, ours included, have no purpose because they arise out of random processes. I am simply proposing that rather than purposeless laws or fields preexisting, it is a supreme intelligence that preexists, and that the ideas of this intelligence give rise to laws of physics that create universes, so call this underlying intelligence God. Both origin explanations are equally logical and equally beyond proof at this time, but there is a purpose behind the God interpretation.

5 The Occam's Razor Objection

Some argue against the existence of the multiverse on a theological or scientific basis, but by appealing to Occam's Razor. Some argue that it is absurd to hypothesise a vast number of universes (perhaps an infinite number) just to explain our own, therefore it is simplest to assume that only one universe exists, which theists will say was created by God and which non-theists will say occurred naturally.

Occam’s razor does not say the simplest idea is usually the right one - it says that the simplest explanation is usually the right one. The introduction of a god is a more complex explanation because the multiverse is explained using existing laws of nature, whereas the god hypothesis requires the introduction of an additional entity which may not exist and which many argue is beyond human comprehension.