Susskind’s Response to Mithani and Vilenkin: Let’s Play Pretend

Alex Vilenkin has been a staunch supporter of a temporally finite universe.  In spite of the numerous papers and lectures he has given showing that the universe cannot avoid a beginning and the “eternal” models are only eternal into the future, many atheists refuse to acknowledge that all of physical reality had a beginning and are still arguing that it is has an eternal past.  Even Alan Guth, who is the “G” in the BGV Theorem, says they have been able to “prove” the universe had a beginning, yet he still thinks it may be eternal.  I have often wondered what other scientists say about Vilenkin’s work, since if he had made a significant error in his analyses of the other models, surely someone would have said something more than quibble over what constitutes a beginning.

I came across a short paper by Leonard Susskind where he responds to the paper, “Did the universe have a beginning?” by Mithani and Vilenkin which I summarized here (spoiler- the answer is Yes!).  Susskind is a popular physicist that makes frequent appearances on science programs like Nova.  In this paper, he “will argue the opposite point of view; namely, for all practical purposes, the universe was past-eternal.” 

 

He uses a thought experiment of a semi-infinite city called, Hilbertville, to represent the multi-verse.  It has a boundary at x=0, but the goes to infinity at x>0.  The observers of Hilbertville are trying to see the boundary of the city.  Those close to the boundary can see it, but those who are very far away cannot.  Since most of the observers will statistically be too far away to see the boundary of the city, he concludes the city may as well not have a boundary and the same goes for a beginning to the universe.

“Combing the Mithani-Vilenkin's observations with the ones in this note, we may conclude that there is a beginning, but in any kind of inflating cosmology the odds strongly (infinitely) favor the beginning to be so far in the past that it is effectively at minus infinity.”

Susskind didn’t say Mithani and Vilenkin were wrong in their analyses of other model types.  Susskind agreed the evidence indicates there was a beginning.  Instead he said the beginning of the universe (or multi-verse) was probably so far in the past that the universe may as well be eternal for us observers on Earth.  That’s akin to saying ‘the evidence says there was a beginning, and while I acknowledge that’s the evidence, I can still pretend there wasn’t a beginning and ignore all implications of a beginning’.  Atheists get upset when Christians quote Romans 1 and claim they suppress the knowledge of God, but with a response like this, can you blame us?

 

Vilenkin and Mithani: Did the Universe Have a Beginning?

Frequently when debating with an atheist I will bring up the beginning of the universe as evidence for a creator and the typical response is, “We don’t know that the universe had a beginning.”  Their claim is that models exist that are eternal, so the universe may not have had a beginning.  So far, this claim has not been supported by the math.  Alex Vilenkin and Audrey Mithani wrote a paper called, “Did the universe have a beginning?” where they examine,

“three candidate scenarios which seem to allow the possibility that the universe could have existed forever with no initial singularity: eternal inflation, cyclic evolution, and the emergent universe.”

 

                                          

Here is what they wrote about each type of model:

Eternal Inflation Models

These models theorize that there was a period of exponential inflation during the very early phases of the Big Bang.  These type of models solve several questions surrounding the standard Big Bang model, which makes it a likely candidate for being plausible.  One of the consequences of these models is that they predict a multi-verse.  Once started inflation will continue into the infinite future.  The science magazines love to talk about this prediction as possible evidence for a multi-verse, but there’s a catch; the BGV Theorem has shown that if on average the universe is expanding, the universe/multiverse had a beginning. 

“Therefore, although inflation may be eternal in the future, it cannot be extended indefinitely to the past.”

Cyclic Models

Another type of model examined is the cyclic model.  These are the models that have an infinite series of big bangs followed by big crunches.  Entropy gives these models a couple of problems:

1).  With each bang/crunch cycle, the entropy continues to increase.  If the universe were eternal, we should have run out of usable energy and entered a state of “thermal death”.

2).  One way to avoid the thermal death scenario is to have each subsequent expansion get bigger and bigger for an infinite amount of time.  If this were to happen, the universe would on average be expanding more than it is contracting, which brings you back to the BGV theorem and a beginning.

Emergent Universe Models

In the emergent universe scenario, the universe is in a static quantum state until the “cosmic egg” decides to crack open.  This would bypass the requirement of the BGV theorem such that the average state of the universe would not be one of expansion.  In order for this type of model to succeed, a couple of conditions must be met.

“First, the universe should be stable, so that quantum fluctuations will not push it to expansion or contraction. In addition, it should contain some mechanism to exit the stationary regime and begin inflation.”

Vilenkin and Mithani demonstrate that quantum instability exists because there is a non-zero probability of quantum collapse, so the universe could not have existed in a quantum state for an infinite amount of time.

“Since the tunneling probability is nonzero, the simple harmonic universe cannot last forever…..there do not seem to be any matter sources that admit solutions that are immune to collapse”

Summary

While in scientific terms we are not 100% certain that the universe had a beginning, since nothing in science is considered to be 100% certain, all of the evidence we have suggests that it does.  This paper demonstrates that “eternal” models can only be eternal in one direction; the future. 

“At this point, it seems that the answer to this question is probably yes.  Here we have addressed three scenarios which seemed to offer a way to avoid a beginning, and have found that none of them can actually be eternal in the past.”

The Multi-Verse: Part III – The Height of Irrationality

The idea of the multi-verse is often used to hand-wave away difficulties with a naturalistic explanation for our universe.  Unfortunately, all the multi-verse does is move the goal posts back a level; the questions in this universe do not go away by adding an infinite number of universes.  There are many scientific and philosophical implications or unanswered questions with the idea of the multi-verse without a designer, so here’s a short list: 

 

 

The laws of physics are independent of the universe

The laws of physics are needed to allow a universe to form prior to the universe forming, if not temporally then ontologically.  As Alex Vilenkin said in this interview,

 

“The same laws that describe the evolution of the universe also describe the appearance of the universe; its coming into being.  This seems to suggest that the laws were there prior to the universe itself…..The laws of physics have some platonic existence which is independent of the universe.” – Alex Vilenkin

A platonic existence is the idea that abstract objects, like numbers, shapes, truth statements, etc exist in an independent reality as opposed to being ideas that do not really exist.  Vilenkin is saying the laws of physics exist in an independent reality.  Appealing to a multi-verse does not explain away the laws of physics, since it too needs laws of physics to exist.  The next question is, are the laws of physics brute fact (exist out of necessity), chance, or is there a mind behind the math?  I’ll deal with chance next.  If the laws of physics are brute fact, then it is impossible to have a universe with different laws of physics.  I don’t know of any scientist that holds this view, but even if true, does not explain how the constants within those laws are fine-tuned for a life-permitting universe.  The fine-tuning of the universe for life still cries out for an explanation. 

 

Using the multi-verse to escape a designer is a logical fallacy

The reason the multi-verse has gainedpopularity in scientific circles is due to the fine-tuning problem, which many (not all) atheists acknowledge as the most compelling evidence for a designer, although not compelling enough.  In order to avoid a designer or appealing to the Anthropic Principle (it has to be that way or we wouldn’t exist aka “just have faith”), atheists are now appealing to the idea of an infinite number of universes to increase the probability/chance that a universe tuned to 10^-120 is closer to 1.  There are a couple of issues with this:

 

1).  In order to have an infinite number of universes with different physical constants and early universe conditions, a constant scrambler or some other mechanism must exist to set these different constants prior to these universes forming.  Where does the randomness come from?  Is this cosmic slot machine also tuned to randomly spit out universes with different constants?

2).  This commits the Inverse Gambler’s Fallacy which is “the fallacy of concluding, on the basis of an unlikely outcome of a random process, that the process is likely to have occurred many times before.”  In other words, simply saying that ‘the odds are extremely low that a universe such as ours would form; therefore, there must be an infinite number of universes’ is a logical fallacy.

 

Occam’s Razor

Occam’s Razor is a principle that states that when there are competing hypotheses, the one with the fewest assumptions should be selected.  This is not a principle that refutes logic or science, nor does it prove/disprove anything.  What it does implicate is that one should not posit an infinite number of universes just to explain one universe when the simple explanation of a mind fits the data for the fine-tuning and other discoveries that have been made.

 

The multi-verse also had a beginning

In this video, Alan Guth describes his theory of eternal inflation, which is the leading theory for what happened just prior to the Big Bang (the Big Bang is the result of inflation).  It is not a complete theory, as the he acknowledges, but has made some predictions that have been confirmed.  One of the predictions of this theory is that once inflation starts, the universe expands forever into the future and can repeat by creating more universes.  The caveat to the theory of eternal inflation is that the “eternal” part only goes one way; the future.  Something had to start the first inflating universe.

 

“….we’ve been able to “prove” mathematically that it’s in fact not possible to extrapolate arbitrarily far into the past.  Somewhere if you extrapolate backwards into the past [], somewhere [was] the beginning of inflation.” – Alan Guth

Eternal Inflation is only one of several theories for the origin of the universe and is compatible with some of them like string theory; however, the BGV theorem says if a universe has an average state of expansion, it had a beginning.  Alan Guth is the G in BGV.  This also applies to the multi-verse.  If the multi-verse is expanding, it too had a beginning.  Is it possible the multi-verse is not expanding?  It’s difficult to imagine a multi-verse full of expanding universes that is not also expanding, but if the multi-verse is not expanding it must be infinitely large which leads toproblems.

 

Another reason to believe the multi-verse had a beginning is the 2^nd Law of Thermodynamics.  As Vilenkin explained, the laws of physics had to exist prior to the universe to allow the universe to form at all.  If our universe was formed out of the multi-verse and the laws of physics were already in place, there is no valid reason to believe the 2^nd Law of Thermodynamics does not also apply to the multi-verse.  This also suggests a beginning since the multi-verse should have hit thermal equilibrium an infinite time ago.

 

If the multi-verse does exist, it also had a beginning and requires a cause.

 

Our universe would not be an isolated system

Many of the equations used in the laws of physics are based on the assumption that the universe is an isolated system and have been repeatedly confirmed.  If the multi-verse exists and has interacted with our universe in any way, our universe would not be an isolated system.  This would call into question many things we have observed and think we know about our universe.  Should the multi-verse be discovered our laws of physics may not need adjusting, but I think observational confirmation of our equations lends credence to the idea that our universe has not been impacted by an outside universe. 

 

Multi-verse of the gaps

I don’t know if there are an infinite number of universes or not.  No one does; there isn’t any evidence for or against it.  The issue I have with the multi-verse is that it is being used to hand-wave away evidence for a designer.  It provides an intellectual escape by allowing people to ignore the problems with naturalistic explanations and then claim there is no evidence for a designer.  It’s the “multi-verse of the gaps” argument.  With an infinite number of universes, anything and everything can be explained away.  A theory that can explain anything explains nothing.

 

Why is there something, rather than nothing?

The multi-verse does not answer one of the fundamental questions, “Why is there something rather than nothing?” 

 

The multi-verse can substitute for religion

The multi-verse can be used as a religion substitute.  One of the benefits to having an infinite number of universes is the comfort of knowing that you will live again in another universe.  Tommaso Dorigo laments this new trend in this article where he says,

 

“Indeed, long ago man invented religion as a way to explain what he could not figure out by logical methods, as well as to accept his own mortality: religion made acceptable the concept of death, as well as give an explanation to other natural phenomena. And man is now inventing the multiverse in what appears to me a new, albeit well disguised, attempt in the same direction. One as reassuring and sweet as the idea of an almighty entity….We might be immortal after all….if we accept that the universe is a multiverse unlimited in time, with bubbles continuously regenerated, we must conclude that we are bound to live again not one, but an infinite number of times.”

 

 

Your evil twin is wreaking havoc somewhere

One of the fun implications of an infinite number of universes is the reality that every individual exists in oneor more other universes.  There are an infinite number of me! 

 

“some calculations suggest that a reality with infinite space and infinite universes would necessarily have to repeat itself sometimes, leading to the conclusion that copies of Earth and everyone on it exist somewhere else out there.” – Daniel Mortlock

 

Could one of these copies be my evil twin?  Maybe in another universe I’m an anti-theist, or apologist for atheism…..or a super hero or super villain! 

 

 

The multi-verse is best explained by God

A transcendent mind is still the best explanation for our laws of physics, the fine-tuning of those laws, the unreasonable effectiveness of mathematics, the origin of the multi-verse, and why there is something rather than nothing.  Adding an infinite number of universes does nothing to explain these and is an intellectual leap without warrant. 

 

 

The idea of multiple universes does not pose a threat to Christianity.  God is free to do as he pleases.  The multi-verse may or may not exist.  We don’t know one way or the other, but using an infinite number of universes as an escape for a designer is not a rational counter-argument to the arguments for theism. 

 

“To postulate a trillion trillion other universes, rather than one God, in order to explain the orderliness of our universe, seems the height of irrationality.” – Richard Swinburne, Is There a God?

 

 

The BGV Theorem

 

In 1927, Georges Lemaître (a priest) proposed the greatest cosmological theory of the last century:  The Big Bang Theory.  There have been numerous confirmations that the Big Bang Theory is true, such as the expansion of the universe and the cosmic microwave background radiation.  This theory has caused a lot of heartburn to the scientific community, since it says that the universe had a beginning.  Atheists do not want the universe to have a beginning because this requires an external agent to cause the change in state and they know what the implications are.  Since the Big Bang Theory was first proposed, atheist scientists have desperately tried to disprove that the universe had a beginning, but unfortunately for them, one cannot disprove the creator of science by using the science he created. 

There have been many additional theories that have been proposed that attempt to incorporate the Big Bang Theory and an eternal universe in order to avoid a beginning.  They have all failed.  The nail was once again put into the coffin in 2003 by a theorem developed by Arvind Borde, Alan Guth, and Alexander Vilenkin known as the Borde, Guth, and Vilenkin (BGV) Theorem.  What they discovered is that any universe that is on average expanding cannot have an infinite past; there is a past boundary.  This rules out all models that try to avoid a cosmic beginning.  Here is the link to their paper and here is a video of Vilenkin explaining the theory.  Here is a quote from the paper.

“Our argument shows that null and timelike geodesics are, in general, past-incomplete in inflationary models, whether or not energy conditions hold, provided only that the averaged expansion condition Hav > 0 holds along these past-directed geodesics. This is a stronger conclusion than the one arrived at in previous work in that we have shown under reasonable assumptions that almost all causal geodesics, when extended to the past of an arbitrary point, reach the boundary of the inflating region of spacetime in a finite proper time (finite affine length, in the null case).”

 

What this is saying is that the only condition that needs to be present to show that ANY universe has a finite past boundary (a beginning) is that it must have an average state of expansion.  This applies to our universe or the multi-verse (if you have faith in such a thing).  There is no doubt in the scientific community that our universe is expanding.  This was discovered by Edwin Hubble in 1929 by looking at the red shift of distant galaxies and repeatedly confirmed.  Since then we have discovered that not only is our universe expanding, but the expansion rate is also accelerating. 

 

“It is said that an argument is what convinces reasonable men and a proof is what it takes to convince even an unreasonable man.  With the proof now in place, cosmologists can no longer hide behind the possibility of a past-eternal universe.  There is no escape, they have to face the problem of a cosmic beginning.” – Alexander Vilenkin

Yet atheist scientists still have trouble admitting that the universe had a beginning and have proposed all kinds of nonsensical, non-falsifiable, faith-based theories to show that the beginning of the universe had a natural cause.  By refusing to follow the evidence, they are saying “Anything, but not God”.

“At this moment it seems as though science will never be able to raise the curtain on the mystery of creation. For the scientist who has lived by his faith in the power of reason, the story ends like a bad dream. He has scaled the mountains of ignorance; he is about to conquer the highest peak; as he pulls himself over the final rock, he is greeted by a band of theologians who have been sitting there for centuries.”  - Robert Jastrow, God and the Astronomers (1978)

 

Genesis 1:1 - In the beginning God created the heavens and the earth. 

 

Good luck to all who try to disprove this.