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Mysterious Cosmos [the anthropic principle]
Nature Magazine ^ | 06 August 2004 | Philip Ball

Posted on 08/07/2004 2:28:51 PM PDT by PatrickHenry

We are lucky to be alive. Extraordinarily lucky. So lucky, in fact, that some people can only see God's hand in our good fortune.

Creationists are fond of pointing out that if you mess with the physical laws of the Universe just a little, we wouldn't be here. For example, if the neutron were just 1% heavier, or the proton 1% lighter, or the electron were to have 20% more electrical charge, then atoms could not exist. There would be no stars, and no life.

But although creationists rejoice in the divine providence that has made the Universe exquisitely contrived to support life, science has long argued for an alternative explanation: the anthropic principle.

The theory has been supported by several leading physicists and astronomers, from Fred Hoyle to Steven Weinberg, who claim it reduces the mystery of our existence to a logical necessity.

Yet the whole idea is roundly trashed by Lee Smolin, a renowned quantum-gravity theorist at the Perimeter Institute in Waterloo, Canada. Smolin asserts, in a preprinted paper on Arxiv1, that the anthropic principle is not a scientific theory at all, because it lacks the basic requirement of falsifiability. It is impossible to prove the anthropic principle wrong, hence it is outside the remit of science.

Circular argument

In truth, the idea always had an air of circularity about it. Crudely put, the anthropic principle states that our universe must look the way it does (that is, primed for life), because if it didn't, we wouldn't be here to argue about it.

But there is a little more sophistication to the idea, which has enabled some researchers to claim that they have put the principle to the test.

The argument usually goes something like this. Let us assume that our Universe is in fact just one of many. This collection of universes is called the multiverse, and its members cannot affect each other in any way. Assume also that physics, by which we mean the fundamental constants of nature, such as Planck's constant and the speed of light, differs more or less at random in each universe.

Most of these universes would be unable to support life. But if there were enough universes, a tiny fraction of them should have just the right parameters to give rise to a cosmos like ours.

Then, the anthropic principle asserts, the intelligent beings in those lucky universes would marvel at how their universe seemed fine-tuned for life, unaware of the countless other universes that remain barren forever. There is no need to invoke God to explain our precarious existence; chance alone suffices.

How one arrives at the multiverse is another matter, but there are possible mechanisms for that. For example, an extension of inflationary theory called eternal inflation suggests that new universes could continually blossom from tiny regions of a precursor universe2.

Alternatively, new universes could be spawned by bouncing black holes. General relativity predicts that sufficiently large stars can collapse without limit under their own gravity to produce a point of space-time that is infinitely small and infinitely dense: the 'singularity' of a black hole. But the quantum-mechanical effects that must take hold at very small scales could in theory cause this collapse to reverse, so the black hole could rebound to form an entirely new universe, which would be a region of space isolated from the universe in which the black hole originally formed.

Put to the test

So in principle one can make new universes, and the anthropic principle could be true. But the real question is, does it actually predict or explain anything? This is what Smolin disputes. He thinks that not only has the idea failed to produce any testable predictions, it cannot do so even in principle.

That is quite a controversial view. Fred Hoyle, for example, used the anthropic principle to successfully predict the existence of a certain energetically excited state of the carbon nucleus. He argued that there would be no life as we know it without carbon, which can only be produced by stars. And he calculated that carbon atoms could only be made in stars in significant quantities if carbon possessed this particular state, which had never at that stage been observed.

Armed with his prediction, astronomers duly looked for the excited state, and found it. It sounds impressive. But Smolin points out that there is nothing anthropic about this reasoning. We know that carbon exists in the Universe irrespective of the existence of life, so life plays no essential role in the logic.

Look at it another way: suppose the predicted state of carbon had not been seen. Would we conclude that the anthropic principle was wrong? Clearly not, because carbon does, in fact, exist, and so do we. We would have to conclude instead that there must be some way of generating carbon other than the one Hoyle proposed, or that his calculations were wrong.

Much the same applies to a prediction of the value of the cosmological constant, made by Steven Weinberg in 1987. The cosmological constant was originally proposed by Einstein as a way of stopping his equations of relativity from predicting an expanding Universe (it was at that time assumed to be static). The idea of such a constant is now back in favour, because it might, this time, be used to rationalize the recently observed acceleration of the Universe's expansion.

Weinberg invoked the anthropic principle to argue that the constant could not be very large, or the Universe would expand too fast for galaxies, stars (or us) to form. A subsequent refinement of his argument predicted that the probability that the cosmological constant has the value suggested by current astrophysical observations is only around 10%.

In other words, the principle seems to make a prediction that, if not stunningly accurate, is certainly plausible. But again, Smolin says, "What is actually doing the work in the arguments is never the existence of life or intelligent observers, but only true observed facts about the universe, such as that carbon and galaxies are plentiful." Our own existence doesn't 'predict' anything.

"The anthropic principle is never going to give falsifiable predictions for the parameters of physics and cosmology," Smolin asserts.

No need for God

So are we forced back to the hypothesis of God? Not at all. Smolin adduces an alternative that, he claims, is scientifically falsifiable. He calls it 'cosmological natural selection'.

The most obvious scientific theory that accounts for a situation that, at first sight, seemed highly improbable is natural selection, points out Smolin. Darwin's idea abolished the need for the Reverend William Paley's heavenly 'watchmaker' to fashion the beautifully 'designed' products of biology.

Smolin believes that a similar principle could save us from making the same mistake about the Universe. This does not involve indulging in any "mysticism about living universes", he reassures us. Rather, he suggests that if there exists some process by which parent universes spawn new universes with small, random changes in their physical parameters, and if the characteristics of a universe determine how many progeny it produces, then fine-tuned universes like ours can arise by cosmological natural selection.

In particular, if new universes are produced by black-hole bounces, then universes in which stars (and thus black holes) can form are 'fitter' than others. After a period of time, you would expect the universes produced by this process to have a set of cosmological parameters that maximizes the number of black holes that can form.

That conclusion helps to explain why we are here, since universes in which complicated structures such as stars and black holes can form are also likely to be hospitable to life, Smolin argues. It also gives us a way to test the idea.

Smolin points to astrophysical measurements that we are able to make now, that could refute cosmological natural selection. For example, the existence of neutron stars with a mass greater than 1.6 times that of the Sun would scupper the idea. So, it could be wrong...but at least it's science.


TOPICS: Culture/Society; Miscellaneous; Philosophy
KEYWORDS: anthropicprinciple; astronomy; cosmology; crevolist
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To: js1138
But genetic engineering was developed by people who mad just-so stories and tested them and made new and better stories.

Nope. The just-so stories did not have anything to do with "genetic engineering".

241 posted on 08/09/2004 3:59:20 PM PDT by AndrewC (I am a Bertrand Russell agnostic, even an atheist.</sarcasm>)
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To: Arthur McGowan
You inserted the word "God" in your "premise 2." ... All I attempted to show was that there is some uncaused being.

This could be all right, if something that makes pond scum look sophisticated will do for an uncaused being. However, that would put your post 22 in the position of injecting the existence of some uncaused thing simpler than pond scum as a rebuttal to a potential claim of the non-existence of God. "It's basic metaphysics. If you say there is no God ..."

You're not making any consistent sense here.

242 posted on 08/09/2004 4:15:54 PM PDT by VadeRetro
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To: VadeRetro

I never said one way or the other what an uncaused being would have to be LIKE. But that question comes after the question of whether it is even POSSIBLE for the entire universe to be composed of caused beings. It is impossible.


243 posted on 08/09/2004 4:40:43 PM PDT by Arthur McGowan
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To: Arthur McGowan
But that question comes after the question of whether it is even POSSIBLE for the entire universe to be composed of caused beings.

Entirely composed of them? The universe seems to be very, very lightly populated with beings. ;)

It is impossible.

I have not seen a demonstration of this point worth the powder to blow it up.

244 posted on 08/09/2004 4:45:56 PM PDT by VadeRetro
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To: VadeRetro; Arthur McGowan
Note that even an abiotically grown, needs-to-evolve-some-to-be-pond-scum being is not totally uncaused. It just not caused by a being. A chain of being need not terminate in an uncaused being.
245 posted on 08/09/2004 4:52:48 PM PDT by VadeRetro
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To: Arthur McGowan
Arthur McGowan wrote:

Denials of the existence of God are actually assertions that there is no being which has some kind of authority over man.

Exactly true. -- "There is no being which has some kind of authority over man", in a Constitutional sense.
Feel free to preach that God exists, but do not insist that your peers obey Him.

There is nothing in the Constitution which asserts or implies that men are not obliged to obey God's law.

Are you claiming that I am obliged to obey your vision of "God's law"?

246 posted on 08/09/2004 4:56:48 PM PDT by tpaine (No man has a natural right to commit aggression on the equal rights of another. - T. Jefferson)
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To: longshadow

Anthropic, uncaused placemarker.


247 posted on 08/09/2004 5:11:54 PM PDT by PatrickHenry (Felix, qui potuit rerum cognoscere causas.)
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To: tpaine
I'm defending my rights to life, liberty, & property, -- from the overzealous extremists of both sides.

So am I. Keep it up. You're much more enjoyable on the drug threads.

248 posted on 08/09/2004 7:29:37 PM PDT by William Terrell (Individuals can exist without government but government can't exist without individuals.)
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To: tpaine

You are obliged to act in accordance with what you sincerely believe to be the truth.

There is still nothing in the Constitution that is relevant to this discussion. The Constitution is NOT the source of any of our rights. It is a legal instrument by which we delegate to the federal government certain functions.


249 posted on 08/09/2004 7:47:33 PM PDT by Arthur McGowan
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To: William Terrell
Strange that you can't quite understand that I'm defending those selfsame freedoms, -- life, liberty, property, -- on those threads, as on here. -- Curious myopia you have, imho.
250 posted on 08/09/2004 7:51:40 PM PDT by tpaine (No man has a natural right to commit aggression on the equal rights of another. - T. Jefferson)
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To: tpaine
Strange that you can't quite understand that I'm defending those selfsame freedoms, -- life, liberty, property, -- on those threads, as on here. -- Curious myopia you have, imho.

So am I. I'm just giving my opinion, from my first post to my last. I don't seek to set those opinions up as laws or prohibitions. The only defense needed against me is philosophical.

251 posted on 08/09/2004 8:09:32 PM PDT by William Terrell (Individuals can exist without government but government can't exist without individuals.)
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To: Arthur McGowan
Exactly true. -- "There is no being which has some kind of authority over man", in a Constitutional sense.
Feel free to preach that God exists, but do not insist that your peers obey Him.

There is nothing in the Constitution which asserts or implies that men are not obliged to obey God's law.

Are you claiming that I am obliged to obey your vision of "God's law"?

There is still nothing in the Constitution that is relevant to this discussion.

Not true. I am guaranteed both freedom ~of~ religion and freedom ~from~ the establishments of any particular religion. Any effort to make me obey your "God's law" would infringe upon my guarantee.

The Constitution is NOT the source of any of our rights. It is a legal instrument by which we delegate to the federal government certain functions.

Yep, -- ALL levels of government in the USA are required to honor the principles of our "Law of the Land". -- Great concept.. Too bad many Americans can't quite seem to 'get it'.

252 posted on 08/09/2004 8:13:49 PM PDT by tpaine (No man has a natural right to commit aggression on the equal rights of another. - T. Jefferson)
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To: VadeRetro

There are books that ably set out the basic metaphysical principles involved. If you haven't seen them, you haven't looked.


253 posted on 08/09/2004 8:14:41 PM PDT by Arthur McGowan
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To: PatrickHenry; Physicist
I'm not good at creationist math, but I believe that 1720 is one of their highest numbers.

LOL! Sorry, I have been off for a bit. Had a paper to complete from the conference I was at last week.

254 posted on 08/09/2004 8:23:06 PM PDT by RadioAstronomer
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To: William Terrell
Strange that you can't quite understand that I'm defending those selfsame freedoms, -- life, liberty, property, -- on those threads, as on here. -- Curious myopia you have, imho.

So am I. I'm just giving my opinion, from my first post to my last. I don't seek to set those opinions up as laws or prohibitions. The only defense needed against me is philosophical.

Very coy wording, but your opposition to principles of constitutional philosophy, -- first to last, -- tells the tale, imho.

255 posted on 08/09/2004 8:31:28 PM PDT by tpaine (No man has a natural right to commit aggression on the equal rights of another. - T. Jefferson)
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To: tpaine
Very coy wording, but your opposition to principles of constitutional philosophy, -- first to last, -- tells the tale, imho.

Oh, not atall. I just said that words on the constitutions don't confir moral strength to an individual, they just serve to remind the state of my tagline.

256 posted on 08/09/2004 8:39:32 PM PDT by William Terrell (Individuals can exist without government but government can't exist without individuals.)
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To: tpaine
History does not record anywhere at any time a religion that has any rational basis. Religion is a crutch for people not strong enough to stand up to the unknown without help......

God is omnipotent, omniscient, and omnibenevolent - it says so right here on the label. If you have a mind capable of believing all three of these divine attributes simultaneously, I have a wonderful bargain for you. No checks, please. Cash and in small bills.

The most preposterous notion that H. sapiens has ever dreamed up is that the Lord God of Creation, Shaper and Ruler of all the Universes, wants the saccharine adoration of His creatures, can be swayed by their prayers, and becomes petulant if He does not receive this flattery. Yet this absurd fantasy, without a shred of evidence to bolster it, pays all the expenses of the oldest, largest, and least productive industry in all history.


There, from the notebooks of Lazarus Long, tells you how I feel about this whole conversation in a nutshell...
257 posted on 08/09/2004 9:14:03 PM PDT by Jaguar1942
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To: tpaine

The Constitution is irrelevant to this discussion because we weren't talking about law at all.

If there is a God, you are obliged to obey his laws. This has nothing to do with any other human being coercing you. And it has nothing to do with the Constitution.


258 posted on 08/09/2004 9:31:16 PM PDT by Arthur McGowan
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To: Arthur McGowan
There is still nothing in the Constitution that is relevant to this discussion.

Not true. I am guaranteed both freedom ~of~ religion and freedom ~from~ the establishments of any particular religion. Any effort to make me obey your "God's law" would infringe upon my guarantee.

The Constitution is NOT the source of any of our rights. It is a legal instrument by which we delegate to the federal government certain functions.

Yep, -- ALL levels of government in the USA are required to honor the principles of our "Law of the Land".
-- Great concept.. Too bad many Americans can't quite seem to 'get it'.

The Constitution is irrelevant to this discussion because we weren't talking about law at all.

Yes, art, you were taking about law. "God's law". Remember?

If there is a God, you are obliged to obey his laws.

There you go again.. Nope, not under our Constitution, Art.. Learn to live with it.

This has nothing to do with any other human being coercing you. And it has nothing to do with the Constitution.

Feel free to rant on kiddo. -- I'm off to bed.

259 posted on 08/09/2004 11:06:56 PM PDT by tpaine (No man has a natural right to commit aggression on the equal rights of another. - T. Jefferson)
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To: whattajoke
re: Your poetic musings, though lovely, certainly don't point to a deity of any sort.)))

But poetry itself points at an intellect which has no rational necessity. Sarcasm does likewise.

260 posted on 08/10/2004 5:44:23 AM PDT by Mamzelle (for a post-neo conservatism)
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