God vs The Multiverse

Click here for God vs The Multiverse: a rational argument for the Existence of One God who intelligently designed one universe.

Sunday, July 29, 2012

God vs The Multiverse (Part 12: The Theory of Inflation)

It will be very helpful for the understanding of the next two posts to watch the video on post seven, between the 8-25 minute marks.

In this post, we'll discuss the theory of inflation, the final pillar of support which Greene brings for the multiverse.  First, we'll begin with an introduction to the concept of inflation, and then differentiate between the theory of inflation and the various models of inflation.  Lastly, we will demonstrate why inflation does not prove the existence of a multiverse.

Inflationary cosmology is one of the most exciting areas of modern physics.  The theory of inflation states that a point very early in the universe's historyit expanded at a very rapid rate before slowing down to the rate of expansion we observe today.

Note: If you are afraid of physics, you can skip until the paragraph "The main idea..." and still get the main point of this post.  However, we recommend reading the entire post, and taking what you can from the next few paragraphs.


According to the theory, the universe was in thermodynamic equilibrium immediately prior to the rapid expansion.  This basically means that the universe was very small with all the energy close together (in causal contact), and therefore (according to the second law of thermodynamics) everything had approximately the same temperature.  It wasn't exactly the same temperature everywhere because of quantum fluctuations (the famous uncertainty principle).

During this short time period (sometimes called the Inflationary Epochthe universe underwent rapid expansion because of unique properties of a hypothesized energy field (called the inflaton field, of course).  In order for inflation to work (without a multiverse), it is critical that there be fine tuning in the inflaton field.  The fine tuning is associated with the potential energy curve of the inflaton field.  The implications of this fine tuning is subject to a similar analysis as previously applied to the constants and the initial conditions; it requires either a Designer or a multiverse to explain.  

When first proposed by Alan Guth in 1981, the theory of inflation was a significant advance in cosmological knowledge because it solved two major problems in cosmology, and was later supported by a prediction consistent with observation.

The first is called the Horizon Problem.  This is essentially the problem of explaining why the cosmological principle is true.  Why does everywhere we look in the observable universe have pretty much the same temperature and other physical properties?  This is explained by the theory of inflation based upon the fact that before inflation started, there was thermodynamic equilibrium in what is now the observable universe.

The second difficulty that inflation solves is the Flatness Problem.  This problem was tied to the fine tuning of the critical density of the universe, but there is a better way to see the problem which has to do with the shape of the universe as governed by General Relativity.  Why is it so flat (so close to a Euclidean space)?  One simple example of this is that on large scales the angles of a triangle sum to 180 degrees.  In a spherical geometry, for example, the angles of a triangle sum to greater than 180 degrees.  The theory of inflation explains this flatness, as inflation smooths out the rapidly expanding space, and renders it very close to the flat space that we observe.

The theory of inflation is a genuine scientific theory that makes a quantitative prediction which is spectacularly confirmed by observation.  It predicts the distribution of energy that we observe in the cosmic microwave background radiation (light that was produced at a later stage of the universe's subsequent evolution) with impressive accuracy.  It also provides an amazing conceptual insight into the early universe.

Remember those small temperature differences caused by quantum fluctuations.  Those small differences end up becoming galaxies.  It's a pretty cool concept.  Inflation blows up the effects of the quantum uncertainty principle to galactic proportions.  The seeds of the galaxies were the temperature irregularities caused by quantum mechanics, which inflation caused to grow into galaxies.

The main idea that is relevant for the proof is to distinguish between the theory of inflation itself (which has some confirmation by observation), and the particular model of inflation which concretizes this theory.  There are many different models to describe the mechanism for inflation (see the Ellis/Carr article which states that there are over 100 competing models).

Some of these models are for eternal inflation (which claims that there are an infinite number of inflating big bangs that randomly occur in an eternal, primordial chaos of an infinite amount of energy, and thus a multiverse).  Other models are for finite inflation (which claims that there is one universe which inflates shortly after the big bang, and no multiverse).

Consider the following oversimplified example which illustrates the difference between a theory and models for a mechanism that explain the theory.  Let's say you take a hot cup of water and place it in a cold room, and find that after a sufficient amount of time the water is the same temperature as the room (i.e., they are in thermodynamic equilibrium as measured by a thermometer).

You can generalize this observation and develop a theory: whenever two objects of different temperatures come into contact with each other for a sufficient amount of time, they end up having the same temperature.

To explain how this happens, you can propose several possible models to describe the mechanism that produces this result: (a) heat in the cup flowed out of the cup into the air of the room, causing the cup to lose its heat; (b) cold of the room flowed out of the air of the room into the cup and cooled it down; (c) some combination of heat and cold exchange; (d) perhaps temperature is related to motion, and the particles in the cup and the particles in the room bumped into each other until they ended up with the same average amount of motion per particle.

These are only four of the many other possible models consistent with the observation that the cup and room are the same temperature.  You can do experiments to test the theory by placing hot objects next to cold objects and seeing if they always end up at the same temperature.  If they do, you can conclude that there is empirical evidence that your theory was correct.

However, which of the four models does this evidence support?  None.  Any of the models can equally explain this experiment.  A proof for the theory is not support for any particular model.  You would need to find some sort of crucial experiment that would work for only one model and not the others.  Only then could you rightly claim that there was evidence for any particular model.

Based upon this point alone, we think it is fairly obvious that the theory of inflation (and its confirmed experimental prediction) does not constitute evidence for the particular model of inflation which contains an infinite number of multiverses. This theory can equally be explained using models that yield only the one universe that we observe, as long as you do not find it impossible to accept the possibility that the inflaton field was fine tuned to produce inflation.  Despite this point, the model of eternal inflation is frequently (and misleadingly) touted as a pillar of support for the multiverse.  

We highly recommend this readable article by Paul Steinhardt in 2011 about the theory of inflation and the model of eternal inflation.  We will be making significant use of it in the next post, where we will discuss the problems of eternal inflation in more depth.  (Chaotic eternal inflation was developed by Andrei Linde in 1986, after it was discovered that Guth's original model for inflation was flawed.  Steinhardt, Linde, and Guth all won the Dirac Medal in 2002 for their work on inflation.)

22 comments:

  1. Side note:

    You mentioned in an earlier post that the import of these posts was that they are fundamental in nature. Do you plan on going through the torah msinai argument as well at some point?(I ask this because I know that I can access the arguments online, either through Rabbi Chait's essay or others, but I feel like an open discussion about the proof and the problems people have with it might facilitate a better understanding of the argument)

    Thanks.

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    1. While we certainly believe it to be valid, we do not plan on going through the historical proof of the Torah. This is because we think it is critical for a person to realize that the knowledge of God's existence is independent of one's knowledge of the veracity of Torah. We therefore think it beneficial not to confuse it with this proof which is conceptually unrelated to the proof of Torah.

      We do recognize that while the knowledge of God's existence is not conceptually dependent on religion and Providence, unfortunately it is often times emotively dependent on them.

      For example, one of Steven Weinberg's biggest problems with this proof is "If God really exists, how do you explain the holocaust?" If you respond that this is not a proof of Divine Providence or (in Einstein's terminology) a Personal God, Weinberg says that he isn't interested in that kind of kind of God.

      While we sympathize with the emotional difficulties involved in trying to make sense of God's justice, we think this is a methodological error. If proper reasoning leads a person to believe in an Intelligent Creator, he should not deny his knowledge because of seemingly irreconcilable difficulties in the area of Providence. They are two different issues, and should be treated as such.

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    2. I understand.

      But where does knowledge of God's existence leave us from a practical perspective? I was just asking because, once again OTHER people have a problem with it, and perhaps there can be great benefit in clarifying the issues, so that we are left with a practical reality of living a religious life. Once again you mentioned that you were posting this proof of God's existence as yesod of torah. So I just thought it would be appropriate to have TMS discussed as well...(but obviously I'm not one to tell you what to discuss on your blog)

      Mio

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    3. The reality of an Intelligent Cause for the universe has great impact on how we view the world. The multiverse theory is a good example. Scientists are wasting their lives in endless speculation about alternate realities because they refuse to accept that there is tremendous wisdom in the creation that comes from an Intelligent source.

      In terms of how one should lead their life, the reality of God's existence is a foundational concept upon which to build. First you lay a solid foundation, and only after to you build upon it.

      The proper idea of God most certainly eliminates many foolish ways of life and philosophies. It is an interesting question what the normative implications of an Intelligent Creator are without bringing in religion.

      It is possible in a different series of posts we will go through the historical proof of Sinai. But we don't want to mix the two issues here.

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  2. The discovery of an intelligent agent that is the source of all observable phenomena has tremendous practical implications. Every time and every area a human being feels he can impose his will on reality is thwarted by the One who made the rules. It essentially forces us to act in accordance with His wisdom, because there is no other path to happiness/fulfillment /success. In fact you can frame much of human life as choosing between a life of illusory fantasy and a life in accordance with and in recognition of the wisdom of that One Intelligent Agent.

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    1. > The discovery of an intelligent agent that is the source of all observable phenomena has tremendous practical implications. Every time and every area a human being feels he can impose his will on reality is thwarted by the One who made the rules.

      Human progress is "imposing our will on reality", of course, within bounds. There is no atheistic scientist who does not believe in these boundaries. What does the knowledge of an "intelligent agent" add, over and above?

      BTW, historically religion stood much in the way of science by telling man "know your place", "we already know how world is" etc. Judaism deserves some credit of not doing much of this (with specific praise going to Maimonides, Gershonides and Maharal of Prague), but then again rabbis had no power in Europe.

      > It essentially forces us to act in accordance with His wisdom

      His "wisdom", whatever it is, is it differnt from physics, and all that's ultimately derived from it (inlcuding psychology)? Because that't the only constraint I'm aware off. This "proof" will not show anything different. If you get off calling it "God's Physics", you're welcome to it, but honestly it makes no difference (or prove it).

      > because there is no other path to happiness/fulfillment /success

      Seriously? I have met many interesting atheists who are living fun and seeming fulfilling lives. They do not seem to be less happy than average to me (though there are some studies indicating psychological benefits of religion, but don't get excited, most subjects were Christians, and I doubt you want to go there). As far as success the 3 richest people in the US are (Gates/Buffett/Ellison) agnostic/agnostic/"religious sceptic". Let's also look at scientific success, while we're at it. I'm aware of a single orthodox Jewish Nobel prize winner, hugely disproportionate to the population.
      Just the facts, mam.

      > RAZ/REF Very well said.

      Dr_Manhattan

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    2. Human progress is not imposing our will on reality, it is actually choosing to live in line with reality. Machines work because we build them in accordance with underlying physical principles. We only discovered those principles because we used our intellect, which is the element that differentiates us from animals. This is another example of acting in accordance with reality, namely the reality of 'man'. Our success is completely dependent on His Will, His Works, His Wisdom - whatever you wanna call it. He determines reality and it doesn't matter if an atheist recognizes Him or not - if he wants to cook his egg in the morning he's banking on the rules that have already been set up.

      Judaism isn't a religion like other religions, even ones that profess to be monotheistic.

      His Wisdom, speaking somewhat loosely, is the source of all knowledge in the universe. So that includes physics and psychology, yes.

      Alright so according to you success equals monetary wealth. I disagree. In fact I think if you try to live your life that way you will get incredibly frustrated, much as you would trying to cook without any gas. ;)

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    3. I guess to say it again - because I don't think I answered you well enough - if there is an Intelligent Agent then it is His Intelligence that determined the nature of our world and our existence. As humans we are also capable of fantasy, delusion, etc. What I am saying is that in order to be successful there is only one way to live - you have to choose based on what that Intelligence set up. Otherwise you are just making decisions based on fantasies, and though it may work for some time (if at all), eventually it will fail, either practically or just emotionally. You'll be frustrated. So the existence of an Intelligent Agent has a big impact on how we should orient ourselves to the world and ourselves.

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  3. Rafi, my point is simple. You say there is Intelligent Agent behind physics/math. I say there is just physics/math. Many other people operate in line with this idea. Many are happy, many do interesting things, many help other people, many make a lot of money. Choose your own criteria of "success" that doesn't involve "believing in Intelligent Agent" (that would be circular) and judge the two groups. I suggest there is little difference. Your assertion if Intelligent Agent does not seem to anything to the behavior of people who simply believe universe is regular and try to discover and take advantage of this fact.

    Dr_Manhattan

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    1. Again, *if* there is an Intelligent Agent, then you owe all success, knowledge, power, and existence to Him. You will also simultaneously recognize that there is no observed phenomena that does not have Him as its ultimate source. In other words the universe has a certain uniformity, it is all in the category of "His works" or "creation", if you get my drift. Everything we experience is part of that creation. This applies not only to external phenomena (physics) but internal phenomena, the psyche. My point is this knowledge/perspective changes how we relate to ourselves, not simply how we relate to the external. Not only that but if there is an Intelligent Agent then it is not simply that we are acting in accordance with a 'dead' universe that happens to be regular, but we are acting in accordance with the design of that Intelligent Agent. So the proper and true life of a human is a life of submission as opposed to a mere practical submission for the sake of building machines to make our lives easier and setting up democracy so that we kill each other less (in theory, lol). It turns out that, again, to be successful and actually be a human we have to follow His design, and as such we can accurately be said to serve Him as a serf follows the will of the king.

      If this is just one of a near infinite number of multiverses then there is nothing outside of practical considerations. If two people were alone in the desert and one killed the other there would be no moral consequence, only some psychological ones, but that doesn't really matter. It would be equally as real or equally as moral of a choice to not murder. If, however, there is an Intelligent Agent and there is a purpose to all of this, then it comes out that human beings have the capacity to thwart this purpose or act against their design. Then we have a real claim against murdering, or idolatry, or having no restraint in our sexual lives. So it does make a difference whether it is just physics/math or if there is a purpose to our existence and this universe.

      The difference, again, is whether or not you exploit the regularity for practical concerns only or if you recognize that finding and living your place in the regularity is what it means to be human and practical considerations are completely secondary to this aim. Good discussion though and I appreciate the lack of snark.

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  4. Rafi, I am not sure I understand your point so well.

    If one posits an intelligent designer of the universe, what relevance does that have to morality? If there is no idea of providence and your concept of God is simply a being who willed the universe into creation, it would seem the knowledge the we are living in a world designed by that intelligent agent alone is insufficient to make much of a difference.

    I believe that the only thing that one could say is this (and perhaps this is what you are trying to say): if humans were created, then their creation clearly had a design and a purpose. If we were brought into existence by design, then it behooves us to investigate what the purpose of our existence is or should be. We should strive to live in line with our purpose and our nature. Otherwise, everything is completely random and it doesn't make any difference. I don't know that this is even necessarily directly relevant to happiness or success. As such, I do not get Dr. Manhattan's point about wealth or nobel prizes. One who spends his life pursuing wealth is foolish. Similarly, one who spends his life in the pursuit of accolades such as nobel prizes is just as foolish. Those people clearly care most about the approval of others and such an approach is doomed to failure. The fact that people who don't believe in a creator have acquired these accolades appears irrelevant to the whole discussion.

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    1. The only thing I can say is that if there is a purpose then there is something we can go against. If there is no purpose then any moral behavior is not really moral it is just practically expedient. There's no design to go against, there's no concept of sin, unless your concept of sin is doing what isn't practical. If there is a purpose then morality has a value in and of itself, because there is a design that we can choose to act in accordance with.

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    2. You don't need to posit Providence to realize that morality exists if He exists and designed this world for a purpose. The fact that this world exists for a purpose (which implies Intelligent Agent) and we can go against our purpose gives rise to a real concept of morality and a systematic way of living - uncovering our purpose and living it.

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    3. That is basically what I was trying to say. The only question I have is can we figure out what our purpose is without the concept of providence?

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    4. That's a great question! I have some ideas but I should think about it a bit more... do you have any thoughts on the matter?

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    5. I have been thinking about this as well. I have not come to a conclusion yet. If you have any concrete ideas, please share. RAZ/REF, please feel free to share your thoughts as well.

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  5. I mean just based upon the idea of an intelligent creator alone

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    1. These are great questions. We don't feel capable of satisfactorily resolving them. However, we have some thoughts and approaches we would like to share. Perhaps the readers can add, question or comment.

      1. The primary value of this proof is that is provides very significant, fundamental knowledge regarding the universe- that it has an Intelligent Designer. Knowledge is its own value, besides for any practical value that it may give us. This knowledge is fundamental in nature and provides a solid Foundation and a Pillar for all other knowledge. The pursuit of knowledge without this Foundation is baseless and results in multiverses and other speculations. (See our second comment above for more on this point)

      This being said, it is difficult to derive anything about the Designer's "plan" and to arrive at practical implications of the proof. However, we think that there are some avenues in which there may be practical impacts to the knowledge of the existence of an Intelligent Designer.

      2. Values and Ethics: Given that the universe is Designed, one can study the universe and attempt to derive knowledge about the Design. The knowledge of an Intelligent Designer opens up a path of philosophy to try to derive ethics and values based upon His Existence. We do not know exactly how to proceed in such a path, but questions such as: Is it wrong to destroy the planet? to murder? may be approachable. (As Rafi mentioned above, these and all other moral questions seem merely practical and fundamentally baseless in a chaotic multiverse.) The Torah seems to maintain that Avraham Avinu arrived at certain knowledge from this route. However, we do not know his arguments.

      3. Possibility of Revelation: There are many people who have never and will never investigate the veracity of religions's claims of Revelation to the masses because they assume that God does not exist, and therefore cannot reveal Himself. Once one has the knowledge that there is an Intelligent Designer to the universe, it seems to be a natural question to ask if He has ever "Spoken" to His intelligent creatures to tell them about his Design or their place in the Design. Thus the proof can be a stimulus for further investigation whether any of these claims have real evidence.

      4. Psychological effect: It seems to us that there are psychological implications whether one (a) believes that he lives in a chaotic multiverse with the illusion of order in this small corner which we call our universe, or (b) he knows that he lives in a universe Intelligently Designed by a Creator. We don't think there is a study testing this effect nor can we define the exact implications. However, it seems clear to us that this is the case.

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    2. I really like point number 3. Thanks for putting all of those points out there.

      I was going to say to Jeff that it seems like what Avraham did was figure out true ethics based on his knowledge of One God. If I come up with some more concrete ideas I'll post them in this thread.

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  6. Hi,

    First of all, thank you for your articles on this subject. It is very interesting and helpful.

    I read that there is some debate as to the value of Alpha in the universe. They say there may be some evidence that it varies very slightly throughout the universe.

    Does that impact your argument either way?

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    1. We're glad we're able to provide help on these issues.

      If science were to discover that Alpha (the fine structure constant) were to vary slightly in different portions on the observable universe (which as far as we are aware, there is no convincing evidence to support this assumption though it seems to crop up from time to time), this would not materially affect the main line of thought in the argument.

      In so far as Alpha was still within the limited range which allowed for the complex ordered universe to form, the arguments against the first two theories mentioned in Stage One would still apply, as well as the mystery of what determined the range. (See post 6)

      In terms of it's impact on the questions against multiverse theory, it would weaken to a degree the specific problem that multiverse theory posits that the constants vary in all the other hypothetical universes, which is something that as of today there is no evidence to support. (Hence the term 'constants'. See post 7 for more on this particular problem).

      We don't think it would help for any of the other, far more fundamental problems with multiverse theory. Also, while it would show that science was mistaken (which is always a possibility) about Alpha being a constant, but that it is rather a variable, it would give no reason to believe that other constants (like the cosmological constant) were also variables.

      In addition, it would have no conceptual bearing on the low entropy problem with the initial conditions of the big bang (Post 4) which is a very different type of phenomenon than a constant of nature.

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