Fine tuning: a discussion for the rest of us mortals

Hi cavediver,I know it's not very popular right now (though I've never minded it myself), but didn't the Gaia hypothesis make an attempt at answering your question? Have you read about it? Do you dislike it?More information hereI know it won't do very well in answering questions about why the speed of light is a constant, for example, but then that's not really a job for the life sciences.Mickin edit: the website i linked to says "biological responses tend to regulate the state of the Earth's environment in their favor.". I think a more modern interpretation would be that the Earth's physical/chemical environment and its biological life are in an evolutionary feedback loop. If life happens to make a more oxygen-rich environment, you get oxygen-respiring organisms evolving. etc. etc. But if the environment reaches a physical limit, then life is forced to adapt to it. That process of adaptation changes the Earth's environment. The process goes on...added in edit, again: I just discovered that most of the stuff on the web about the gaia hypothesis is pretty awful...This message has been edited by mick, 11-26-2005 05:08 PMThis message has been edited by mick, 11-26-2005 05:13 PM

Just to give a more concrete example:The concentration of oxygen in surface-level air on Earth is about 20%, and this appears to be very "fine-tuned" for the survival of all sorts of animal life.But in fact the 20% concentration of oxygen is the result of a very long term process of coevolution between physical planetary systems and the evolutionary diversification of life: More information hereThere was no fine tuning, apart from the fine tuning carried out by long term biological processes and geological events.MickThis message has been edited by mick, 11-26-2005 05:25 PM

Hi Mick,Yeah, Gaia is a great mechanism for creating "fine tuning", although obviously wrt biological/chemical parameters rather than the fundemental constants (as you point out). Read about it and like it. If a bunch of prokaryotes can completely turn the atmosphere around (albeit taking 2,000,000,000 years to do it), then biosphere self-regulation doesn't look so incredible...Lovelock always comes across well. Interesting how recently he was reluctantly admitting the necessity for further fission power generation. That upset a few greens who thought he was on their side

I've also never really felt the force of the AP. What are we supposed to get from it?I take it that those who put forth the argument would say it implies a there is a supernatural being who created the universe for us; but can't we push the question back further?What are the chances that there would exist a supernatural being which had the ability and desire to create a universe that was fine-tuned for humanity's existence? Out of all the possible characteristics God could have had, it turns out they are all not only compatible, but "fine-tuned," for our existence.Are we to conclude that God exists for our existence? Does everything that exists exist for us?

more to the point ... why create one that is "fine tuned" instead of one that is stable?

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we are limited in our ability to understand
by our ability to understand

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RebelAAmerican.Zen[Deist
... to learn ... to think ... to live ... to laugh ...
to share.

I'm not so sure that "fine-tuned" is synonomous with unstable.

Of course ... if there are mechanisms that hold a system within a fine-tuned envelope or that tend to return it to that envelope from any pertubation, but the anthropic concept is based on incredulity that it could be so arranged without outside help.And, of course, the answer is job security.

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we are limited in our ability to understand
by our ability to understand

​

RebelAAmerican.Zen[Deist
... to learn ... to think ... to live ... to laugh ...
to share.

Not at all. Some use it as a basis for teleology (Tipler to some extent) but this is not the case in general.The Weak AP is simply the observation that conditions in this universe must be such as to allow us to exist. It does not answer why those conditions have those values, only that they must have those values. Is this useful? Well, in some ways. It identifies those conditions that appear fine-tuned, and encourages further invetsigation to determine why they have those values. You are now moving into Strong AP territory. Slighter weaker than this is the point that for us to exist, you need the entire universe. The constants that give rise to our existence are the same constants that determine the size of the universe, its consituents, its age at our time of (first) observation, etc.The Design argument would be that, yes, everything that exists, exists for our existence. There's not much I can think of that you can remove from the universe without seriously impacting the possibility of intelligent life.If it has a religious connotation, I've always found the AP more Bhuddist in approach than Western religion.

Just thought I'd post this for fun...Page not found | Crooks and LiarsWell I'm convinced...So who designed those pineapples then?hahaOn a more serious note: we have John Mackay in the UK at the moment. He will spend 3 days at a school in Lancashire. Hopefully, he'll be using the ID banana argument...This message has been edited by melatonin, 04-23-2006 04:23 PM

Of course the flaw in the banana argument is that many of the characteristics of the commercial banana, like most commercial agriculture and livestock, are the result of selective breeding, not Nature or God.

Exactly. And the fellow in the video forgot to point out that--like superstition--bananas don't taste nearly as good as they once did.Of course, if he did, he'd probably argue for the delicious pre-Fall Uber-Banana as a Golden Age proof of God.When you look above all for proof that you are right, you can find it everywhere. That clip would be a wonderful classroom exercise in confirmation bias.

Lo all this may be somewhat off topic, but AP bugs the shit out of me.
Doesn't the idea that a life permitting universe is extremely unlikely depend entirely on their being more than one?
Also doesn't it depend on our ability to check how many contain life?
As it stands, with only one universe, aren't the odds 1-0 in favour?
Looked at from an internal perspective, the odds of life bearing planets existing in this universe other than Earth, are very much in favour of lots more.
http://curious.astro.cornell.edu/question.php?number=447
An estimated 100million in our galaxy alone
So basicly, with no other universe to check we'd have to say that, the odds are totally in favour of life, as long as the universe has the physics it has (it does) and contains the elements it does (it does).
So unless you can say that these things are also incredibly fine tuned (I don't see how you could) the AP is pointless (for this use).
And it seems to say fine tuning's not real anyway.

Shh writes

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An estimated 100million in our galaxy alone

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First of all, please use the paragraph structure.Even Karen Masters, the person who claimed the estimate, admitted that all of these estimates are based on very incomplete data. While it is true that these estimates came from the best data we have, which isn't very much, you have to understand that we still only have ONE single data point to work from when we're dealing with planets that have life. As far as we know, there aren't any other like Earth.

Possibly, but this is not what the AP states. It does not talk in terms of probabilities, only necessities to life. It is about identifying those properties of the universe that have to be just so for us to exist. The question is then, what makes these properties take those values? Are they fine tuned by natural means (lack of spatial curavture via inflation) or are they free parameters (G, alpha, etc).The supposedly free parameters are where the probabilities possibly come in. If G falls outisde a critical range, universes fly apart and disperse before stars can coalesce or collapse far too soon. Change alpha and stars don't shine... Given enough trial universes, you will have a subset where the parameters are such that life can exist. If only one universe, then questions of design creep in. I'm not convinced of this. I think it's still wide open... I can certainly envisage the earth being the only life-abundant planet in the Galaxy.

cavediver Are these proerties of the universe that need to be just so for us to exist also necessary in order for the universe to we live in to exist as well? If so, with vast regions of space so completely inhospitable to intelligent life { I would imagine being awful close to 100 %} that we exist strikes me as accidental and not planned.
The AP seems to be applicable only when we focus on the Earth and our intelligent life, otherwise it seems a moot point.