The title of my post is a question everProgressive asked me in my last post. If we look at the question on the surface I could answer it in three little words, "I don't know". However, everProgressive asked me in context to a post in which I said that it was my opinion that scientific reasoning rules out the existence of God. Perhaps I am wrong, but I think everProgressive knows that I don't know how the universe began, and is in reality asking, "If you don't know how the universe began, then how can scientific reasoning rule out the existence of God?" To answer that question requires quite a lot more than three simple words.
Before I begin let me just say that everProgressive doesn't know how the universe began either. I can say this with some confidence since no one really knows how it began. But, just because we don't know, doesn't mean that we don't have ideas. And it is my belief that scientific reasoning is the best way to evaluate those ideas. We can use it to rule out some ideas, we can use it to compare different ideas.
So what are the ideas we have about the origin of the universe. There are quite a few. It is beyond both the scope of this post and my expertise to cover all of them so I will limit myself to a few I am familiar with. First, let me say that I have intentionally referred to these as "ideas". I do this because I do not think any of them rise to the level of a "scientific theory". A scientific theory is a well-tested hypothesis. So far the ideas we have about how the universe began have not been testable (Although one I will talk about does make a testable prediction but even there I don't think that whatever the answer to that prediction turns out to be is definitive enough to rule it in or out). Perhaps as we develop better and better mathematics some ideas may rise to the level of "testable hypothesis" and from that may emerge a "theory". I hope so.
A reader with a passing familiarity with modern cosmology might infer that I think the Big Bang theory does not rise to the level of "scientific theory". Nothing could be further from the truth. It is an excellent scientific theory. It has been very well tested and has survived all tests. True, it has been modified because of the results we have gotten from those tests but that is the way it is with all science. The thing about the Big Bang theory is that contrary to popular belief it is NOT a theory about how the universe began. It is a theory about how the universe EXPANDED an instant after the universe (as we know it) began until now. The reason it is not about how the universe began is because there is a fundamental inconsistency between the mathematics of relativity and the mathematics of quantum mechanics that rears its ugly head when applied to small time scales, very small distances, and tremendous gravity. There are two places that this discrepency becomes significant; (1) in black holes, and (2) the origin of the universe. Thus, the Big Bang theory as we know it tells us nothing about the origin of the universe. That is speculation and that is why I refer to these speculations as "ideas".
I am going to classify these speculations into three categories. The first is the ETERNAL UNIVERSE category. These ideas postulate that the universe may not have always been as we know it now. It may have existed in one form or another forever. Under these ideas, the universe (everything there is and always will be) never had a beginning. The second is the UNIVERSE FROM NOTHING ideas. These ideas state that the universe began with the Big Bang. The third one is the SUPERNATURAL UNIVERSE. These ideas state that the universe began as the result of God. With these as our options, let's subject them to scientific reasoning.
The first of the eternal universe theories I'll call the LONG DORMANT COSMIC EGG. The Big Bang theory says that the universe as we know it began about 13.7 billion years ago from a VERY SMALL (possibly point-like) AREA OF SPACE. All the matter/energy that we can see or measure in the universe began from a very small point of space that expanded into the observable (and probably larger) universe. But the Big Bang doesn't say what that area of space was like before the expansion began. Perhaps it was there all along. For reasons unknown to us it just never expanded until 13.7 billion years ago.
The first thing we need to ask ourselves is what does this idea explain. Well, one thing it explains is the origin of matter and energy. We do not have to come up with any reason for how the universe got its matter in the first place. According to this idea, it was always sitting right there all balled up in that point. That is about all that it explains.
The second question to ask is what COULD it explain. It could explain the ANTHROPIC PROBLEM. Cosmologists who look at the universe and measure its properties have made some interesting observations. There are certain numbers that we need to stick into equations that can only be measured. These numbers are not generated out of the Big Bang theory. These numbers are called the FUNDAMENTAL CONSTANTS of the universe. We know what they are only from measuring them. When we stick these numbers into our equations we get mathematics that makes reasonable models of how the universe expanded. But we have no idea of why these constants are what they are. Perhaps they could have been something else. One interesting observation is that if we substitute different numbers into our equations and see what type of universe we would have come up with, we find that most often these universe either collapse back onto themselves before life (as we know it) could have had a chance to form, or expands so rapidly that the universe effectively evaporates before life (as we know it) would have had a chance to form. or stars would have never formed in which case the universe would have consisted of nothing but hydrogen and helium and without carbon life (as we know it) could never have formed. This has caused some cosmologists to remark that the fundamental constants seem to be "fine-tuned" to allow life to exist in this universe. This is the anthropic problem that any theory on the origin of the universe must explain.
The "long dormant cosmic egg" model of the universe COULD explain the anthropic problem by saying that is what they happened to be so the universe had no option other than to have those particular fundamental constants. It could also explain it by saying that we have absolutely no way of knowing how the fundamental constants were determined in the first place. Perhaps the ones the present universe has are the only ones that it could have had. This makes the prediction that with further investigation of the universe we will find out that the fundamental constants are actually tied to each other in complex ways such that they MUST be the way they are. In other words, we will find out that what are now fundamental constants determinable only by observation actually do arise out of theory (when our theory progresses).
The final question to ask is, "How well does the theory explain what it COULD explain and is there anything that it can't explain no matter how hard it tries?" I don't know of anything that it can't explain. But I do find the explanation for the anthropic problem is a bit too ad hoc for my liking. Why would the dormant cosmic egg just happen to have the "right" fundamental constants? Also so far nothing in our examination of the cosmos suggests that the fundamental constant MUST be as they are.
The second of the eternal universe ideas I will call the NATURALLY SELECTED UNIVERSE idea. It was first proposed by Lee Smolin, a theoretical physicist then at Penn State. The Big Bang tells us that the universe as we know it started in state of ultrahigh density and minimal volume. What does that sound like? The answer is a BLACK HOLE. Smolin postulated that black holes are place where new universes are being made. If that is the case, then our universe would be the parent of an estimated 10^15 or more daughter universes. In other words, universe reproduce. Anytime you have a reproducing entity you have the potential for natural selection to take place. If the fundamental constants of daughter universes are similar (but not necessarily the same), then you could have a universe with any combination of fundamental properties you may want and over many generations you would end up with a population of universes that would NATURALLY have fundamental constants that were fine-tuned for the production of black holes. What is needed in a universe to produce black holes? You need a universe that has long-lived stars and massive stars. This is EXACTLY the same thing that cosmologists have said is what makes our universe so "fine-tuned" for life. So under Smolin's scenario, the universe is actually fine-tuned (by a perfectly natural means) for the production of black holes which just happen to be properties that are conducive for life to develop.
One exciting aspect of this idea is that it makes A TESTABLE PREDICTION. It predicts that our universe DOES have fundamental constants that are near optimal for the production of black holes. In other words, this comes close to rising up to the level of theory. The question is then, "Are the fundamental constants of our universe near optimal for producing black holes?" Well, it is certainly very good at doing so. At the moment it appears to be much better at producing black holes than it is at producing life. There are an estimated 10^15 black holes in our universe, and the only known place that life exists is the earth. However, among cosmologists who mathematical skills are much better than mine, it seems that a consensus is beginning to form that there are combinations of fundamental constants that would produce black holes better than the ones that we see in our observable universe. So while I don't think this idea is totally blown out of the water yet, it isn't looking great at this time.
Let's look at the universe from nothing ideas. The first of these I'll call the BASIC MODEL. This model says that the universe began (mass and energy) from nothing totally uncaused at the instant the Big Bang began. The first objection is that everything in the universe must have a cause. With the advent of quantum mechanics we can dismiss this objection. Heisenberg's Uncertainty principle says that there are certain quantities that are tied together in ways such that the more accurately you measure one quantity you MUST introduce greater uncertainty in the other quantity. Two such quantities so entwined are position and momentum. The more confined in space a particle must be the greater is the uncertainty of its mass and velocity, the two components that make up momentum. In very restricted areas the uncertainty in mass and velocity is great enough that a pair of particles can pop into existence from absolutely nowhere without violating any law of nature. These are called VIRTUAL PARTICLES. In fact, the production of virtual particles has been EXPERIMENTALLY CONFIRMED.
It is called the CASIMIR EFFECT. The experiment went something like this: two uncharged plates were placed in close aposition to each other. The space between the plates was very limited while the space on the outside of the plates was essentially infinite. It is much more likely that virtual particles will be produced outside of the plates than between them. Normally virtual particles will collapse back on each other destroying themselves before there is a chance to measure them. However, occasionally they will fly far enough apart that they will not destroy each other. Then they can react with material world. In the experimental design of the Casimir effect they are much more likely to hit the outside of the plates than the inside. As a result one should see the plates being forced together. Indeed, this is exactly what was seen. The plates experienced an attractive force that could not be explained by gravity.
The present version of the Big Bang theory is the INFLATIONARY MODEL. It explains why the cosmic microwave background is so uniform (there is less than 1 millionth of a degree difference no matter what part of empty space you look). What it says is that the first instant of the Big bang was marked by a rapid expansion of space. The "edge" of space went from a point to a huge distance in a matter of a miniscule fraction of a second. This inflation was much faster than the speed of light. It is OK to do that because the "edge" of space is not matter. Einstein's theories of relativity only forbids matter from moving faster than the speed of light. So what was created was a bunch of empty space. This is the perfect place for the creation of virtual particles. The basic model says that all of the matter in the universe began as virtual particle formation.
It does not explain the anthropic problem however. It says that either we are VERY fortunate, or else there really wasn't a choice in what the fundamental constants of the universe could be. That brings us to the second of the "universe from nothing" ideas. I'll call this the MULTIVERSE idea.
When we measure the cosmic microwave background radiation what we are actually seeing is photons that arose from a very early stage of the universe. These photons have been travelling over 13 billion years! They are just now making it to us. But the entire universe started off from a point-like area, certainly many orders of magnitude smaller than 13 billion light years. The only way this can happen is if the early inflationary period proceeded much faster than the speed of light. That means that whatever space those photons started from could only just now be affecting us. There are other areas of space that have not yet had time to affect us in any way. The technical term for this is these areas of space are not in causal contact with us.
What does this have to do with anything? It means that if something caused our area of space to have its particular set of fundamental constants, it is unlikely that the same thing cause these other areas of space to have their set of fundamental constants. In other words it is likely that different areas of space could have different fundamental constants. At the instant of the Big Bang there could have been areas that would have any set of fundamental constant that you may be able to imagine. In that case, some areas may have had constants conducive to undergo inflation, others would have evaporated away and yet others would have collapsed onto themselves. Only the ones with fundamental constnats conducive for long lived universes (capable of producing life) would still be around. Therefore it is no wonder that we find ourselves in such a region of space.
The Mutiverse idea tells us where the matter and energy of the universe came from (same place as that proposed by the basic model) AND why it also solves the anthropic problem. To me it has the fewest drawbacks of any. It is the one I think most likely. At least of the naturalistic models. What about the third class, the supernatural universes.
These are VERY different models. I will group all of them together under the rubrick GOD DID IT. Most of the people behind it think that it explains everything. Where did the matter and energy come from? God did it. How do we explain the anthropic problem? God did it. Sounds good, but scientific reasoning is about to make it sound a lot less good.
The first question to ask is, "What God did it?" I suppose that everProgressive would say the god of Christianity. But why not Zeus, the Flying Spaghetti Monster, the Invisible Pink Unicorn, or Rex the wonder gremlin? One could argue Zeus is unlikely because Greek myths portray him as not existing until on after the universe was created. One could equally well argue that it is unlikely to be the Christian God because the way the bible claims the universe was created does not correspond very well with what we know. So the last three gods have the advantage there. I am sure that everProgressive would not find that too appealing.
The second question to ask is, "How did God do it?" I don't know what everProgressive would say but the most common answer I get from Christians who actually answer it is that God spoke the universe into existence. How did he do that? To my knowledge that isn't possible. So what this answer boils down to is that God did it magically. I'm sorry, but invoking the inexplicable is no explanation for the unexplained. In other words, "God did it" doesn't explain it.
The third question to ask is, "If God explains the existence of the universe, then what explains the existence of God?" Most theists say that God was always here. But if anything can always be here then why not go with one of the eternal universe ideas. It saves you having to postulate the prior existence of God AND a realm of the supernatural. In other words, it is a much simpler explanation.
The fourth question to ask is, "What possible finding would the God-did-it idea NOT explain?". The answer is since God is supposed to be omnipotent and therefore COULD do anything, anything could be explained as being the product of God. Thus, the God-did-it hypothesis limits absolutely no possibility and therefore gives you no information. It is in reality no explanation at all. Therefore I do not even have to consider it. That is why I can dismiss it by scientific reasoning.
Regards,
Darwin's Beagle
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