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Author Topic:   Fine tuning: a discussion for the rest of us mortals
cavediver
Member (Idle past 3643 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 61 of 83 (318777)
06-07-2006 1:46 PM
Reply to: Message 60 by sidelined
06-07-2006 1:24 PM


Re: off topic?
First off, while we are sticking to weak AP concepts, there really is nothing metaphysical about all of this.
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?
I don't differentiate the two. The universe we see is one capable of bringing forth intelligent life (obviously) The vast stretches of inhospitable space are just as necessary to our existence as the oxygen in our atmosphere -it is very hard to imagine the latter without the former.

This message is a reply to:
 Message 60 by sidelined, posted 06-07-2006 1:24 PM sidelined has replied

Replies to this message:
 Message 62 by sidelined, posted 06-07-2006 1:54 PM cavediver has replied

  
sidelined
Member (Idle past 5908 days)
Posts: 3435
From: Edmonton Alberta Canada
Joined: 08-30-2003


Message 62 of 83 (318780)
06-07-2006 1:54 PM
Reply to: Message 61 by cavediver
06-07-2006 1:46 PM


Re: off topic?
cavediver
The vast stretches of inhospitable space are just as necessary to our existence as the oxygen in our atmosphere
Then the is not fine tuned for life but that our vanishling tiny portion of it happens to be in a position where the factors that would prevent us from occuring are balanced just so.
This does not seems very anthropic to me but a lucky conincidence of fortune like an oasis in a desert.

This message is a reply to:
 Message 61 by cavediver, posted 06-07-2006 1:46 PM cavediver has replied

Replies to this message:
 Message 64 by cavediver, posted 06-07-2006 2:13 PM sidelined has replied

  
Shh
Inactive Member


Message 63 of 83 (318781)
06-07-2006 1:55 PM


Rgb says
First of all, please use the paragraph structure.
Sure, sorry bout that.
Rgb continues
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.
I'm pretty sure this dealt with the capailty for life not the fact itself. If we're only dealing in planets which have life then at one point in history, we'd have to say that no life was possible.
Mars could possibly have supported life in the past, and possibly could again. That's enough to show that Earth isn't unique.
Cavedigger says
If only one universe, then questions of design creep in.
Then doesn't the "if" have to be answered before we can move on?
..and continues
I think it's still wide open... I can certainly envisage the earth being the only life-abundant planet in the Galaxy.
Why? The vast majority of the values needed are common to the entire galaxy. If all that's neccesary after this is to be within a certain range of proximty to a sun, and water, how likely is it that there's only one planet with these two values?
Mars seems to have, or have had, both.
If the question is how many life bearing planets at any one specific time, then sure, it's posssible there's only one, but across all time?
The BBC did a Horizon special about this recently, with computer simulations varying the strength and existence of physical laws, and almost none of the universes failed, most were just different.
I can't find a link atm, but will continue looking
Sidelined says
The AP seems to be applicable only when we focus on the Earth and our intelligent life, otherwise it seems a moot point.
And I agree.

Replies to this message:
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cavediver
Member (Idle past 3643 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 64 of 83 (318784)
06-07-2006 2:13 PM
Reply to: Message 62 by sidelined
06-07-2006 1:54 PM


Re: off topic?
Then the [universe] is not fine tuned for life but that our vanishling tiny portion of it happens to be in a position where the factors that would prevent us from occuring are balanced just so.
No, it is everything. Alpha and G are critical to life, and are universals through-out the universe. They dictate whether stars are possible, or molecules. There is plenty of fine-tuning before we even get to the stage of asking what is needed to get a decent planet somewhere.
But still you seem to think the AP (or WAP at least) is saying something it is not. The WAP is essentially: Properties of the Universe are such that allow the possibility of intelligent life (human terrestrial life). It's not really a big deal. It is used simply to draw attention towards those very properties for further investigation.
Why is the universe 13.7 billion years old? It has to be around this age for us to observe it - any earlier and there hasn't been sufficient time for observers to arrive - auto-tuning. End of story.
Why does alpha have its value? If it did not, there would be no observers - fine tuned. What has caused alpha to take this value? We don't know... yet.

This message is a reply to:
 Message 62 by sidelined, posted 06-07-2006 1:54 PM sidelined has replied

Replies to this message:
 Message 75 by sidelined, posted 06-08-2006 1:22 PM cavediver has replied

  
rgb
Inactive Member


Message 65 of 83 (318785)
06-07-2006 2:19 PM
Reply to: Message 63 by Shh
06-07-2006 1:55 PM


Shh writes
quote:
I'm pretty sure this dealt with the capailty for life not the fact itself.
I'm not sure you understood my point before. Even if we deal with the planets for the capacity for life, we are still dealing with, at best, 3 datapoints (Venus, Earth, and Mars). That's THREE datapoints.
Because of our limited technology right now, we can only find planetary systems that have gigantic gas giants within the so-called habitable zones.
quote:
If we're only dealing in planets which have life then at one point in history, we'd have to say that no life was possible.
Well, there wasn't anyone around to say anything, yes?
quote:
That's enough to show that Earth isn't unique.
Uniqueness is a subjective word. Personally, I'd say that every planetary body is unique.
quote:
Why? The vast majority of the values needed are common to the entire galaxy.
Aside from the fact that the Sun is a typical main sequence star, we know almost nothing else.
But for a starter, could you name some of these "values"?

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cavediver
Member (Idle past 3643 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 66 of 83 (318786)
06-07-2006 2:23 PM
Reply to: Message 63 by Shh
06-07-2006 1:55 PM


Then doesn't the "if" have to be answered before we can move on?
No, becasue you are into serious metaphysics at this point.
Mars seems to have, or have had, both.
Exactly. Had. No more. It's not only the values you need but enormous external stability over a vast time. It took 2Gyears for the prokaryotes to transform our atmosphere to something viable for future evolution - half the age of the earth - almost a sixth the age of the universe!!!
If the question is how many life bearing planets at any one specific time, then sure, it's posssible there's only one, but across all time?
Well, you can't go back too far, as you run out of building materials. The future, on the other hand, is a better prospect.
The BBC did a Horizon special about this recently, with computer simulations varying the strength and existence of physical laws, and almost none of the universes failed, most were just different.
Wish I'd seen it, but then I have destroyed too many TV sets after watching bad science on Horizon
I would be very interested in what they thought to change.

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ikabod
Member (Idle past 4493 days)
Posts: 365
From: UK
Joined: 03-13-2006


Message 67 of 83 (318971)
06-08-2006 3:20 AM
Reply to: Message 1 by coffee_addict
11-18-2005 5:26 PM


The fine tuning argument can be rebuffed from the single stand point of what it is fine tuned for ..
from observation the universer is fine tuned to produces hydrogen atoms .. have you seen how many there are ?????? its unreally ..
no thats silly its tine tuned to make water good old H20 ... no thats silly .. why water ...
no its tuned to make life . .. see now thats a good reason right .. because ...err umm ...
no its fine tuned to make computers .. yes thats it all comes together now ..
H to H20 to life to humans to computers .....the XBOX is the reason for the universe ... every thing is so carefully tuned so that the end product comes into being ...The XBOX ....
Please anywhere in my logic chain find a fault .. if there is fine tuning its for a reason .. with out the universe being as it is no XBOX's

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 Message 1 by coffee_addict, posted 11-18-2005 5:26 PM coffee_addict has not replied

Replies to this message:
 Message 68 by cavediver, posted 06-08-2006 6:02 AM ikabod has replied

  
cavediver
Member (Idle past 3643 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 68 of 83 (318985)
06-08-2006 6:02 AM
Reply to: Message 67 by ikabod
06-08-2006 3:20 AM


The fine tuning argument can be rebuffed from the single stand point of what it is fine tuned for
Not really. The universe appears exceptionally fine-tuned for our existence (and hydrogen, water, computers and Xboxes). The question is why does it appear so?
You can claim that there is only one universe and we arrived simply by improbable chance in a universe with lots of room for improbable possibilites. That ignores the fact that no matter how large the universe, the global pararmeters are still mysteriously fine tuned to our existence.
Obviously you can argue that it was designed that way by some intelligent designer, but that is rather unsatisfactory as it implies a bit of fudge to this otherwise incredible creation.
You can claim that the parameters are randomly distributed, and given sufficient (infinite?) "universes", either sequentially or not, universes will arise that are suitably configured for human life and we are destined to observe such universes. I also find this a little unsatisfactory. Perhaps better to consider a larger universe with regions that span all possible values of the (now no longer) global parameters, such that some areas are life-possible.
Where does that leave me? Well, I have some rather odd ideas about it all

This message is a reply to:
 Message 67 by ikabod, posted 06-08-2006 3:20 AM ikabod has replied

Replies to this message:
 Message 69 by ikabod, posted 06-08-2006 6:43 AM cavediver has replied

  
ikabod
Member (Idle past 4493 days)
Posts: 365
From: UK
Joined: 03-13-2006


Message 69 of 83 (318989)
06-08-2006 6:43 AM
Reply to: Message 68 by cavediver
06-08-2006 6:02 AM


no you do not need infinite numbers of universes , you do not need fine tuning , you do not need a designer ..
what you need is the history of the universe to be as it is ... every random event has to have happened in the way it did .. then you get to this point .... it no longer matters that the chance of this sequence happening being so unlikly as to appear impossible .. it has happened and we are living in the proof .. that is what happened ... from todays view the universe is fine tuned for x box's , .. but at what point did that become clear .. hmm in 250bc ,1066 ad , 1556 ad 1901 ad , 1999 ad or when the dinosaurs where the dominate type of creature ?? ...
there is nothing mysterious about whty we fit so well into the universe .. we are part of it .. nothing that we are made of is odd or rare in the universe .. there are no strangle cubes floating in space producing the element Qq.. that element that is vital but only reacts in humans .. we share every component in comman with the rocks ice's gases stars clouds across the universe ...
where is the specfic fine tuning just for us ?? this planet is not idea for us .. vast area to hot , hot cold , to wet to dry , to high , to much volcanic activite , areas that after a few years will no longer grow you food crops , vast numbers of hotile and leathal organisms , solar radiation and flares , lumps of rock and ice falling on us , finite resorces , a star which will run out of fuel in the same universe where you are limited by the speed of light so travel to another star is going to take ages ....
look at the evidence and we are clining on dispite the universe rather than it supporting us .....

This message is a reply to:
 Message 68 by cavediver, posted 06-08-2006 6:02 AM cavediver has replied

Replies to this message:
 Message 70 by cavediver, posted 06-08-2006 7:35 AM ikabod has replied

  
cavediver
Member (Idle past 3643 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 70 of 83 (318998)
06-08-2006 7:35 AM
Reply to: Message 69 by ikabod
06-08-2006 6:43 AM


look at the evidence and we are clining on dispite the universe rather than it supporting us .....
You have a lot to learn about this universe
Try altering alpha (the fine structure constant) by a touch and notice how all the stars go out - proton-proton chain is very dependent upon alpha. Shift G a bit (or lambda) and the universe flies apart so quickly stars don't even get chance to coalesce, or in the other direction all the matter quickly forms black holes.
I'm not so interested in the Earth being compatible with life; rather the universe being compatible with stars and planets. This requires knowing why G and alpha have the values they do.

This message is a reply to:
 Message 69 by ikabod, posted 06-08-2006 6:43 AM ikabod has replied

Replies to this message:
 Message 71 by ikabod, posted 06-08-2006 8:27 AM cavediver has replied

  
ikabod
Member (Idle past 4493 days)
Posts: 365
From: UK
Joined: 03-13-2006


Message 71 of 83 (319014)
06-08-2006 8:27 AM
Reply to: Message 70 by cavediver
06-08-2006 7:35 AM


Quote"You have a lot to learn about this universe" ... by what measure ?? i know all i need to know to exsist ..
Quote "I'm not so interested in the Earth being compatible with life; rather the universe being compatible with stars and planets. This requires knowing why G and alpha have the values they do. "
so what you are really saying is you are looking for a reason for the universe .. you are assuming it has a reason beyond being itself ...
on what basis are you making your assumption of that there is a reason ?? what part of reality are you unsatisfied with that creates this need ??
Ok so if G was less there would be no stars .. interesting fact but irreverent .. you might as well say if gods exsisted and one of them feed on stars there would be no stars ... you are dealing with things that are Hypothetical , you might as well say .. how odd the universe is so fine tuned that France lost the Napoleonic wars .. how was that achived .. if the French had delt with Spain before invading Russia the universe would be different ... true but its not the case ..
In your universe with a lower value of G with no stars would the universe exsist ?? yes .. and would not a observer marvel at the fine tuning to get just the right density of gas clouds so as to produce feli ( feli being the equiviltent of life ) gosh good job the value of G isnt a bit higher or all those usfull elements would be locked up in great balls of fire and harmful radiation , im sure glad we alive in a universe where atoms float free and as easly access other wise feli ( or YBox's)could not exsist .....

This message is a reply to:
 Message 70 by cavediver, posted 06-08-2006 7:35 AM cavediver has replied

Replies to this message:
 Message 72 by cavediver, posted 06-08-2006 9:16 AM ikabod has replied

  
cavediver
Member (Idle past 3643 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 72 of 83 (319024)
06-08-2006 9:16 AM
Reply to: Message 71 by ikabod
06-08-2006 8:27 AM


so what you are really saying is you are looking for a reason for the universe
No, of course not. I'm a cosmologist/physicist and I want to know why the universe is the way it is. If I was happy to just say, oh that's the way it is, I wouldn't have devoted so much of my life to the pursuit of science.
you are dealing with things that are Hypothetical
Welcome to theoretical phsyics...
In your universe with a lower value of G with no stars would the universe exsist ?? yes .. and would not a observer marvel at the fine tuning to get just the right density of gas clouds so as to produce feli
Possibly. The question is what is the space of all possible universes, and what sub-space is compatible with intelligent life? It appears that for most value of G and alpha, no structure (and hence probably life) at all would be possible.

This message is a reply to:
 Message 71 by ikabod, posted 06-08-2006 8:27 AM ikabod has replied

Replies to this message:
 Message 73 by ikabod, posted 06-08-2006 10:22 AM cavediver has replied

  
ikabod
Member (Idle past 4493 days)
Posts: 365
From: UK
Joined: 03-13-2006


Message 73 of 83 (319039)
06-08-2006 10:22 AM
Reply to: Message 72 by cavediver
06-08-2006 9:16 AM


right , i think is see your vantage point now , you are not interested in say "oh that's the way it is" no lets explore and exprience what is ..
you want to step outside of what is ..and ask why did we get to the point we are at ...
you would like to run time backwards and re run the universe to see if things took a different course would we get to the same point ,as we are now, ever
i assume that you hold a view that there was scope at the start of the universe ( assuming it has one ) for the Laws and constants governing it to have the option of being different .
is it fair to say that you would not be satisfied by the answer that by chance this is the way the universe turned out ..out of all the possiblites we got this one , ?
do you know what sort of answer you are looking for ??

This message is a reply to:
 Message 72 by cavediver, posted 06-08-2006 9:16 AM cavediver has replied

Replies to this message:
 Message 74 by cavediver, posted 06-08-2006 12:41 PM ikabod has replied

  
cavediver
Member (Idle past 3643 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 74 of 83 (319078)
06-08-2006 12:41 PM
Reply to: Message 73 by ikabod
06-08-2006 10:22 AM


you want to step outside of what is
A good way of putting it
you would like to run time backwards and re run the universe to see if things took a different course would we get to the same point ,as we are now, ever
Well, that's not very GR. When I "step outside", I'm stepping outside time. That is how we study space-time. So I try to look at the universe as a whole unit, and ask what possible universes there could be.
i assume that you hold a view that there was scope at the start of the universe ( assuming it has one ) for the Laws and constants governing it to have the option of being different.
This is a very deep metaphysical point. I actually probably hold the opposite view. I would like to get to a point of seeing the universe "as is" as wholly necessary. This starts to verge towards something similar to strong AP, but I stay clear of any religious overtones.
is it fair to say that you would not be satisfied by the answer that by chance this is the way the universe turned out ..out of all the possiblites we got this one , ?
It depends what you mean by "this one". If you mean this exact one with Earth and you and me, then I think that's asking a bit much. But yes, I don't think we got these laws and this type of universe by chance. I think it was necessary.
do you know what sort of answer you are looking for ??
Not yet I have a strong inkling that existence and even life and conciousness are all tied up with mathematics in a semi/pseudo Platonic sense but I'm stil working on it. Only I don't get paid to work on it any more which is a bit crap...

This message is a reply to:
 Message 73 by ikabod, posted 06-08-2006 10:22 AM ikabod has replied

Replies to this message:
 Message 78 by ikabod, posted 06-09-2006 3:26 AM cavediver has replied

  
sidelined
Member (Idle past 5908 days)
Posts: 3435
From: Edmonton Alberta Canada
Joined: 08-30-2003


Message 75 of 83 (319099)
06-08-2006 1:22 PM
Reply to: Message 64 by cavediver
06-07-2006 2:13 PM


Re: off topic?
cavediver
No, it is everything. Alpha and G are critical to life, and are universals through-out the universe. They dictate whether stars are possible, or molecules. There is plenty of fine-tuning before we even get to the stage of asking what is needed to get a decent planet somewhere.
But the universe has to come out in some way or other and do we know that other conditions would allow for intelligent life other than our own? If all the conditions up to life but short of intelligence were in place then would the fine tuning arguement still hold?
As Victor Stegner put it "The universe is not fine tuned for humanity. Humanity is fine tuned for the universe."
Why does alpha have its value? If it did not, there would be no observers - fine tuned. What has caused alpha to take this value? We don't know... yet.
Perhaps you could outline the arguements pro and con in the cosmological community? I would find this fascinating.

This message is a reply to:
 Message 64 by cavediver, posted 06-07-2006 2:13 PM cavediver has replied

Replies to this message:
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