Wednesday, July 4, 2007

Faith, Reason and Science, Part V: Paul Davies on the Goldilocks Universe


I had previously posted a discussion of the rationality of a belief in God based on the apparent fine tuning of the universe for intelligent life--the so-called "anthropic principle." British-born cosmologist Paul Davies, now at Arizona State University, has just published a book on just this issue--albeit from a scientific, rather than a religious point of view. The book, The Cosmic Jackpot, is discussed on Salon:

Forget science fiction. If you want to hear some really crazy ideas about the universe, just listen to our leading theoretical physicists. Wish you could travel back in time? You can, according to some interpretations of quantum mechanics. Could there be an infinite number of parallel worlds? Nobel Prize-winning physicist Steven Weinberg considers this a real possibility. Even the big bang, which for decades has been the standard explanation for how the universe started, is getting a second look. Now, many cosmologists speculate that we live in a "multiverse," with big bangs exploding all over the cosmos, each creating its own bubble universe with its own laws of physics. And lucky for us, our bubble turned out to be life-friendly.

But if you really want to start an argument, ask a room full of physicists this question: Are the laws of physics fine-tuned to support life? Many scientists hate this idea -- what's often called "the anthropic principle." They suspect it's a trick to argue for a designer God. But more and more physicists point to various laws of nature that have to be calibrated just right for stars and planets to form and for life to appear. For instance, if gravity were just slightly stronger, the universe would have collapsed long before life evolved. But if gravity were a tiny bit weaker, no galaxies or stars could have formed. If the strong nuclear force had been slightly different, red giant stars would never produce the fusion needed to form heavier atoms like carbon, and the universe would be a vast, lifeless desert. Are these just happy coincidences? The late cosmologist Fred Hoyle called the universe "a put-up job." Princeton physicist Freeman Dyson has suggested that the universe, in some sense, "knew we were coming."

British-born cosmologist Paul Davies calls this cosmic fine-tuning the "Goldilocks Enigma." Like the porridge for the three bears, he says the universe is "just right" for life. Davies is an eminent physicist who's received numerous awards, including the Templeton Prize and the Faraday Prize from the Royal Society in London. His 1992 book "The Mind of God" has become a classic of popular science writing. But his new book, "The Cosmic Jackpot," will challenge even the most open-minded readers. Without ever invoking God, Davies argues for a grand cosmic plan. The universe, he believes, is filled with meaning and purpose.

What Davies proposes is truly mind-bending. Drawing on the bizarre principles of quantum mechanics, he suggests that human beings -- through the sheer act of observation -- may have helped shape the laws of physics billions of years ago. What's more, he says the universe seems to work like a giant computer. Indeed, it's possible that's exactly what it is, and we -- like Neo in "The Matrix" -- might just be living in a simulated virtual world.


The article also includes a very interesting interview of Paul Davies. Here are some highlights of what Davies had to say:

A lot of scientists get annoyed by talk about the universe being strangely fine-tuned for life. They see this as a sneaky way to bring religion into scientific explanations for how the universe began. Clearly, you have a different perspective. Why are you so interested in the idea that the universe is just right for life?

All my career, I've been fascinated by the fact that the universe looks not just beautiful but in some sense deeply ingenious. It looks like it's been put together in a way that makes it work exceptionally well. I suppose the most striking example is that the laws of physics and the various parameters that go into those laws seem to be just right for life. If they were even slightly different, it's quite likely there would be no life, no observers, and no people like you and me having this conversation.

How many laws of physics have to be just right for life to be possible?

It's a little hard to write down the definitive list, and part of the reason is that we don't yet know what are the truly fundamental set of physical laws. Changing some of those laws by even a tiny amount would wreck the chances for life. Others seem to have a bit more flexibility. Overall, the total number of these coincidences, or special factors, is probably somewhere between a half a dozen and a dozen. I think most scientists would now agree that you couldn't change things very much and still have life.

So for all of these to happen -- for instance, for carbon to be formed, for gravity to have the precise strength that it does -- you're suggesting that it's more than coincidence that they are just right.

That's right. To just shrug this aside and say, well, if it wasn't that way, we wouldn't be here, would we? -- that's no answer to the question. It's just choosing to sweep it under the carpet. And in the case of the carbon resonance, if the strong force that binds the particles together in the nucleus were a little bit stronger or a little bit weaker, that resonance would be at the wrong energy and there would hardly be any carbon in the universe. So the fact that the underlying laws of physics seem to be just right to make abundant carbon, the essential life-giving element, cries out for an explanation.

But most scientists seem to believe it's just a lucky fluke that we're here. They say there's no inherent reason that all of these physical laws happen to have just the right properties so that carbon could form, the Earth could develop, and human beings could evolve.

You're absolutely right. Most scientists would say it's a lucky fluke. And if it hadn't happened, we wouldn't be here, so we won't bother to ask what's going on. Now, that point of view might have been tenable 20 years ago when the laws of physics were simply regarded as just there -- as God-given or existing for no reason -- and the form they had just happens to be the form they had. But with the search for the final unification of physics, there's been more of a thrust towards saying, we won't just accept the laws of physics as given. We'll ask, how did those laws come to be? Are they the ultimate set of laws? Or are they just effective at low energies or in our region of the universe?

. . .

There are some obvious questions about the big bang. Can we really talk about it coming out of nothing? Don't we have to ask, wasn't there something that caused the big bang?

Many people fall into that trap. But Augustine, in the fifth century, pointed out that the world was made with time, not in time. I think he got this exactly right. Of course, most people think that there must have been a previous event that caused whatever event we're talking about. But this is simply not the case. We now know that time itself is part of the physical universe. And when we talk about the big bang in a simplified model, then we're talking about not only matter and energy coming into being, but space and time as well. So there was no time before the big bang. The big bang was the origin of time.

People want to ask, what happened before the big bang, or what caused the big bang? But in a simple picture where there's just one universe, the big bang can be the ultimate origin of space and time as well as matter and energy. So unless the universe has always existed, you're faced with the problem that time itself comes into existence. And any attempt to talk about causation has to be couched in terms of something that comes after the beginning and not before the beginning ... because there was no before.

There are some obvious religious implications to all of this. My sense is that a lot of Jews and Christians are actually quite delighted with the big bang -- the idea that the universe was created out of nothing. It seems to correspond to the story of creation in Genesis.

I think there's a misunderstanding by religious people if they think that creation ex nihilo is anything like the big bang. People misunderstand what creation ex nihilo is about. It's not that there existed a God within time who was there for all eternity and then at some particular moment, on a whim, decided, "I'm going to make a universe" and then pressed a button that made the big bang. That raises exactly the objection that Augustine was addressing: What was God doing before making the universe? If the universe was a good idea, why wasn't it made an infinite time ago?

I might also say that it's always a bad idea for people to decide what to believe on religious grounds and then to cherry-pick the scientific facts to fit, because these facts are likely to change. And we may find that the big-bang theory goes out of favor at some point in the future. And then what? Religious people will have backed the wrong horse. So it's fraught with danger to seize on these cosmological ideas. But I personally think we can draw the conclusion that we live in a universe that's deeply imbued with meaning and purpose.

But most scientists would probably say there's no inherent meaning or purpose to the universe. It's an absurd universe. There's a famous quote from the Nobel Prize-winning physicist Steven Weinberg, "The more the universe seems comprehensible, the more it also seems pointless." Weinberg is an atheist who believes there's no ultimate point to human existence. Is he just wrong?

He and I would agree entirely on the scientific facts and would simply draw opposite conclusions from them. It's really an argument about whether the bottle is half full or half empty. Words like "meaning" and "purpose" are human categories, derived from human experience, and so we're projecting them onto nature and saying, well, the best way of understanding the universe is to say it behaves in a purpose-like manner.


In the end, Davies comes close to accepting what looks like a religious view of all of this, and even notes that many of the alternative explanations for the fine-tuning, most notably the many worlds theory, were developed by scientists for the very purpose of avoiding the apparent theological implications of these facts. Still, even Davies shys away from talk of a God or intelligent designer:

Are you saying that if you go back to the first few seconds of the universe, somehow the laws of nature were put in place so that intelligent life would arise billions of years later?

I'm not saying that an intelligent designer figured it all out and created the universe with a set of laws that would bring intelligent beings into existence.

You want to stay away from God.

I want to stay away from a pre-existing cosmic magician who is there within time, for all eternity, and then brings the universe into being as part of a preconceived plan. I think that's just a naive, silly idea that doesn't fit the leanings of most theologians these days and doesn't fit the scientific facts. I don't want that. That's a horrible idea. But I see no reason why there can't be a teleological component in the evolution of the universe, which includes things like meaning and purpose. So instead of appealing to something outside the universe -- a completely unexplained being -- I'm talking about something that emerges within the universe. It's a more natural view. We're trying to construct a picture of the universe which is based thoroughly on science but where there is still room for something like meaning and purpose. So people can see their own individual lives as part of a grand cosmic scheme that has some meaning to it. We're not just, as Steven Weinberg would say, pointless accidents in a universe that has no meaning or purpose. I think we can do better than that.

Do you think one reason the multiverse theory has become so popular in recent years is to keep the whole idea of God at bay?

Yes.

Because a lot of physicists seem to be at a loss for how to explain this cosmic fine-tuning. But with the multiverse, you can say there are an infinite number of universes and we just happen to be lucky to live in one that supports life.

There's no doubt that the popularity of the multiverse is due to the fact that it superficially gives a ready explanation for why the universe is bio-friendly. Twenty years ago, people didn't want to talk about this fine-tuning because they were embarrassed. It looked like the hand of a creator. Then along came the possibility of a multiverse, and suddenly they're happy to talk about it because it looks like there's a ready explanation. Only those universes in which there can be life get observed, and all the rest go unobserved. Notice, however, that it's far from a complete explanation of existence. You still have to make a huge number of assumptions. You need a universe-generating mechanism to give you all these universes. You need a set of laws that can be scattered across these universes, distributed in some way, according to some algorithm. You're no better off than saying there is an unexplained God.

Even the scientific explanations for the universe are rooted in a particular type of theological thinking. They're trying to explain the world by appealing to something outside of it. And I think the time has come to move beyond that. We can -- if we try hard enough -- come up with a complete explanation of existence from within the universe, without appealing to something mystical or magical lying beyond it. I think the scientists who are anti-God but appeal to unexplained sets of laws or an unexplained multiverse are just as much at fault as a naive theist who says there's a mysterious, unexplained God.


You can read the entire interview here.

My take away from this interview is that, in the end, science takes you only so far in deciding the fundamental issue of why we live in a Goldilocks universe. At that point, the decision to believe in God, or not to do so, is a philosophical decision, not a scientific one.

Photo credit: Arizona State University

Photographer: Tom Story

5 comments:

Adam said...

After reading this article, and some related articles on your site, I am inclined to say that you are grasping at straws here. You say that the universe is fine tuned for human life because it is conveniently "pro-theistic".

You neglect however that the strengths of fundamental forces are strictly a product of the properties of the fundamental particles. The models which describe them are based on certain rules which essentially lock down predicted values for strengths, particles, charges, spins, etc. We then test the validity of these models and if they agree with what physicists call the "Standard Model of particle physics" then we use that model as a basis for our best knowledge regarding the simplest particles in the universe.

To claim that because our models are unfounded because we don't have any idea why the models are is merely a loaded question. Science is limited by what we are able to take evidence on. We can not probe the beginning of the universe just yet due to technological limitations; not a lack of interest.

To claim that believing in god is rationalizable merely because scientists don't have the answers now, is being lazy. To say that scientists are avoiding discussion of god is unscientific merely because there is no way that science could ever be used to argue the existence of or inexistence of a deity... But like all things man has come to know, there is a beginning for everything.

It is naive to think that because creationist stories and science agree that the universe had a beginning that religion must all of a sudden be right. We're not dodging the bullet, we're merely trying to keep you from getting excited.

Chuck Blanchard said...

Adam:

You are correct, but only to a point. Most of the parameters that make the universe hospitable to life arise not from the standard model. Some arise from the particular history of the iniverse in the first few seconds. in addition, many of the fundamental constants (such as the ratio of matter to anti-matter) seem not to have any fundamental theoretical underpining that we can find--they are just waht they are. Indeed, many scientists beleive that developments in physics will show that early phase transitions in the universe occur probabilistically rather than deterministically (so there will not be a physical reason for the values of fundamental constants)

Adam said...

This may be true; but just because these parameters are subject to randomness does not mean that these parameters can not be subject to an expected value.

Randomness is not always uniform and is subject to the situation we're working with. For instance, the matter-antimatter problem is an interesting one because one would assume that there would be a symmetry in the number of matter and antimatter particles in the universe; of course this is far from the case... but this only gives further reason to believe that the primitive universe had some overall structure to it.

In all likeliness, these parameters also have some model which have some (may be not a lot) wiggle room in the final value, multiple minima for their potential values, possibly even unstable equilibria amongst some of the parameters...

I realize I'm refering to a "grand unified theory" which you spoke about in another post; but to be realistic, anything which explains a deterministic result (such as why the universe is as we see it today) eventually has to be something we will know absolutely, or will not be able to know (because there will be no way to test the theory). In the event of the latter, we will all simply have to accept the fact that nobody will EVER know.

It's not a question of who's right and who's wrong... It's a question of what really happened, and I'm not looking for what "makes sense", I'm looking for what happened. No matter what that means.

new.atheist said...

If you haven't seen NOVA's Elegant Universe, I'd recommend it highly.

http://www.pbs.org/wgbh/nova/elegant/

You can watch it online, it delves a bit into the constants of the universe, and M-theory.

A belief in a god that can control the fundamental properties of our universe still begs the question; what kind of place does this god live in?

new.atheist said...

What we perceive as "making sense" in our universe is just randomness we are here to observe; give a billion monkeys a billion typewriters & one of them will pop out some Shakespeare.

I like Adam's reply, it makes me think;

Religion is what people would like to think.
Philosophy is what makes most sense.
Science is what is.