Monday, August 22, 2011

Moon Meditations

One of the so-called anthropic coincidences is that in order for a planet to be capable of supporting life it has to have a moon the size and distance of our own in order to stabilize its axis. Some scientists have argued recently that this claim is exaggerated. Specifically, they argue that the larger planets in the solar system would have had a similar effect on the earth, preventing the earth's axis from fluctuating more than about 10 degrees, and that is not significant enough to prevent the existence of life. The earth -- and by extension, any potential life-site -- does not require a moon like the one we have. The article, unfortunately, does not cite a scientific study showing this, only that "astronomers at the University of Idaho have shown" it. Regardless, this is an interesting claim, since most of the studies on the anthropic principle have been in the direction of showing more numerous and more extreme examples of anthropic coincidences, so to have an example going the other way is intriguing. I mentioned this criterion in my series on the anthropic principle (part 1, part 2, part 3, part 4), but my focus on it was in the final entry where I pointed out that having a moon the particular size and distance of our own allows for scientific observation rather than the possibility of life.

Discuss this post at the Quodlibeta Forum

30 comments:

TheOFloinn said...

A moon at that size and distance provides the earth with sufficient tides to enable a progression of sea life to the land. Tidal pools are where much of the action takes place.

Anonymous said...

That's no moon...

Tim O'Neill said...

"... imagine a puddle waking up one morning and thinking, 'This is an interesting world I find myself in, an interesting hole I find myself in, fits me rather neatly, doesn't it? In fact it fits me staggeringly well, so it must have been made to have me in it!' This is such a powerful idea that as the sun rises in the sky and the air heats up and as, gradually, the puddle gets smaller and smaller, it's still frantically hanging on to the notion that everything's going to be all right, because this world was meant to have him in it, was built to have him in it; so the moment he disappears catches him rather by surprise. I think this may be something we need to be on the watch out for."

Smart guy that Douglas Adams.

Anonymous said...

The puddle analogy is a terrible attempt to explain fine tuning.

The mystery of fine tuning isn't that we inhabit a world that seems to be perfectly suited to us as humans. It's that no life AT ALL would be possible if the constants of nature (among other things) weren't fine tuned to a degree that defies explanation.

Atheists really need to get their head around the power of the argument and not try to dismiss it will silly little analogies that don't work. ;)

Tim O'Neill said...

This "fine tuning" crap is about the very worst dumb argument you people ever trot out. So we arose as sentient life in one of the few tiny life-friendly corners of the otherwise life-unfriendly universe? Where else would you expect life to arise - in bits of the universe unfriendly to life? Seriously? Really? Try to think about this a bit, please.

The stupidity of this theistic argument actually makes my brain ache. This is the dumbest thing you people have ever come up with. Seriously.

Anonymous said...

You have again missed the point. Calm down, and THINK.

If we changed any of these "fine tuned" physical realities by the smallest degree, we end up with a universe containing no galaxies, no stars, no planets, no atoms, no molecules, and most importantly, no intelligent life-forms wondering what went wrong.

Do you understand? It's not that we are in a "life friendly corner" of the universe. Without fine tuning life no life *anywhere* in the universe would be possible. That's why the puddle analogy does not work my angry atheist friend.

Why do you think the multiverse is advanced as an explanation at all? If the fine tuning argument were as stupid as you naively appear to believe, a multiverse would not be required as an explanatory hypothesis.

Anonymous said...

I still think Tim is a sock puppet of James Hannam/JPholding.

-Carrier fanboy

Jim S. said...

Tim, I specifically addressed the puddle analogy in part 3, linked in the body of the post. The point of the argument is not amazement that life arose in the part of the universe friendly to life, but that it is enormously implausible that there would be any part of the universe friendly to life. Perhaps the argument fails to demonstrate this, but you'd have to show this rather than just emote about how stupid it is.

Ignorance said...

Relevant issues here are being in the Goldilocks zone, falling in the right mass interval (being a gas giant is not helpful, even if you're in the Goldilocks zone, the atmosphere is just too wild), having a viable atmosphere and overall a workable chemical composition.

Being in a galaxy with a high enough metallicity (that means old enough for such elements to be formed in nuclear fusion and spread through planetary nebulae or supernovae) also increases the chances of having a magnetic core, quite useful against the solar wind. The gravitational influence of other stars is also a factor to consider, physical binaries are likely too chaotic to enable life (and there are many physical binaries) and stellar collisions (very rare in these parts) are not great for life either. Then you would need the type of star that stays around long enough, say an F, G or K type that has not gone too far off the main sequence, red and brown dwarfs have a sufficiently long lifetime but they have a small Goldilocks zone and at a relatively short distance, which can be a drag if the star has a period of increased activity.

Some would also argue for the problems of tidal locks, the importance of plate tectonics and know I what more?

So asking the questions Jim is asking is not dumb at all. It is important to assess these points to consider whether life will be rare or common.

Ignorance said...

About binary stars, aprrox. half of the stars in our galaxy are in binary systems.

Anonymous said...

The co-incidences that Ignorance lay out are important, but I think you could rightly raise the objection Tim does; ie the universe is so vast that somewhere in it, no matter how improbable, all of these anthropic co-incidences are going to occur *somewhere*.

However this objection doesn't work though when you consider the fine tuning required for life *anywhere* in the universe to be possible; things like the expansion rate of the universe, the force of gravity, the level of entropy, etc, etc.

Without the fine tuning of these laws and boundary conditions of the Big Bang we don't get a universe that can support ANY life (or at least, life as we know it).

The fact that we have an extremley improbably solar system with the right size moon, stable orbits, plat tectonics, etc...well that just layers on the improbability.

The overall impression of design is overwhelming in my view. It's the reason I switched from atheism.

Ignorance said...

You are right that the points I raised do not demonstrate one way or another, they just show the importance of further investigation to assess the probabilities involved. The objection that life could still be abundant is still possible, though I think "puddle thinking" is not a good counter.

Aside that, I found Jim's point about the importance of the moon for scientific observation and TheOFloinn's point about tidal pools also interesting takes on the issue.

Matt said...

I understand Tim's point in response to this post alone though. Arguments about the particulars of Earth for supporting life fail due to the puddle analogy so I don't know why anyone bothers with them. Arguments about the constants of the universe itself are where the real discussions are. The particulars about Earth and whatnot would only be effective, I think, if life were plentiful throughout the universe. So far that does not seem to be the case.

Tim O'Neill said...

I had to laugh at the "angry atheist" comment. Yes, because an atheist is disagreeing with you it must mean he is ANGRY. It's a well-known fact that we unbelievers spend our entire lives in a state of apoplexy. *chuckle*

Sorry guys, but I still can't see how this argument has any kind of weight. It's a great big universe, so clearly somewhere (or maybe in a few or even many places) conditions are going to be "just right" for life to arise.

As for the supposed vast "improbability" of the universe being as it is - that still gets a "meh" from me. Of course if the universe was just a bit different we (and galaxies, suns etc) wouldn't exist. But it wasn't. You guys are still doing your usual non sequitur act of tacking a quick "And so our particular deity was involed, the end" on the end of statements that simply don't lead to or require that conclusion.

This is yet another argument that only seems powerful to people already convinced that some God or gods exist and which leaves the rest of us utterly underwhelmed.

Ignorance said...

It's a great big universe, so clearly somewhere (or maybe in a few or even many places) conditions are going to be "just right" for life to arise.

That's an assumption. We only have one known instance of life, so we cannot infer a probability. So the other factors have to be taken into consideration. The result of that could be that we expect it to be very likely that life is common or that we expect it to be very unlikely that there is any life at all. The only way that the vastness of the universe would mean it is bound to happen is if there is an infinite number of stars, but nobody believes that anymore.

As for the supposed vast "improbability" of the universe being as it is - that still gets a "meh" from me. Of course if the universe was just a bit different we (and galaxies, suns etc) wouldn't exist. But it wasn't. You guys are still doing your usual non sequitur act of tacking a quick "And so our particular deity was involed, the end" on the end of statements that simply don't lead to or require that conclusion.

The usual options given are:

1. Chance
2. Necessity
3. Design

Chance would require a multiverse and would require an explanation how those universes were generated and why we would think that there would be any variation in those constants.

Necessity is a fairly strong claim for which we have no evidence, there is nothing in the mathematical equations that would require the constants or the ratio between constants to be as they are. It is pretty odd to claim mathematical necessity for something without either proof or an intuition.

Design is rather straight-forward compared to these two options. However, it does not establish that a particular deity is involved, it just argues for a Creator.

Then there are weird suggestions like fecund universes, which Dawkins seemed to like in The God Delusion, but which few take seriously.

Anonymous said...

[i]I had to laugh at the "angry atheist" comment. Yes, because an atheist is disagreeing with you it must mean he is ANGRY. It's a well-known fact that we unbelievers spend our entire lives in a state of apoplexy. *chuckle*[/i]

I didn't think you were angry because you disagreed with me, I thought you were angry because of the [i]manner[/i] in which you disagreed. Believe me, there are plenty of angry atheists on the Internet...check out the YouTube comments on any William Lane Craig video or atheists getting worked up when their pet theories get challenged (Jesus was a myth, Christianity killed science, etc). For a real laugh check out the comments on the blog 'Debunking Christianity' or 'Dawkins.net'....anyway, I digress; if you're not one of these irrationally angry internet atheists then that's cool.

[i]Sorry guys, but I still can't see how this argument has any kind of weight. It's a great big universe, so clearly somewhere (or maybe in a few or even many places) conditions are going to be "just right" for life to arise.[/i]

You're still missing the point! These finely tuned conditions apply to the universe as a whole, not just in particular 'places' in the universe. For example, 2 finely tuned laws are the speed of light and the force of gravity - are the same everywhere in the universe (at least modern science assumes that they are). There's no pocket of the universe that has a different force of gravity! 

 Let me try to give you one example that should throw the argument into clear light. If the rate of expansion one second after the big bang had been smaller by even one part in a hundred thousand million million, the universe would have recollapsed before it ever reached its present size. 

So if the expansion rate of the universe were not finely tuned to within a hair's breadth, we wouldn't have a universe at all.  

[i]As for the supposed vast "improbability" of the universe being as it is - that still gets a "meh" from me. Of course if the universe was just a bit different we (and galaxies, suns etc) wouldn't exist. But it wasn't. [/i]

Right, but you're still left with an incredible fact that you have left unexplained. The apparent fine tuning of the universe cries out for some kind of explanation. How foolish of us if, upon apprehending this fact, we merely shrug our shoulders and say 'well, that's just the way it is.'

Let me try a well known metaphor: Suppose you are facing a firing squad. Fifty marksmen take aim but they all miss. Of course if they hadn't all missed you wouldn't have survived to ponder the matter. That is a truism. But you wouldn't just shrug your shoulders with a "meh" and leave it at that – you'd be baffled, and would seek some further reason for your good fortune.

[i]You guys are still doing your usual non sequitur act of tacking a quick "And so our particular deity was involed, the end" on the end of statements that simply don't lead to or require that conclusion.[/i]

No. The fine tuning argument does not point to any particular god any I've never seen anyone using the argument draw the conclusion that fine tuning shows [insert diety] exists.  At most it is an argument for deism.

[i]This is yet another argument that only seems powerful to people already convinced that some God or gods exist and which leaves the rest of us utterly underwhelmed.[/i]

It was powerful enough to convince lifelong atheist Antony Flew. I could give you a list of other formerly atheist scientists and philosophers who found the argument convincing. 

Anonymous said...

HTML fail :)

Anonymous said...

I had to laugh at the "angry atheist" comment. Yes, because an atheist is disagreeing with you it must mean he is ANGRY. It's a well-known fact that we unbelievers spend our entire lives in a state of apoplexy. *chuckle*

I didn't think you were angry because you disagreed with me, I thought you were angry because of the [i]manner[/i] in which you disagreed. Believe me, there are plenty of angry atheists on the Internet...check out the YouTube comments on any William Lane Craig video or atheists getting worked up when their pet theories get challenged (Jesus was a myth, Christianity killed science, etc). For a real laugh check out the comments on the blog 'Debunking Christianity' or 'Dawkins.net'....anyway, I digress; if you're not one of these irrationally angry internet atheists then that's cool.

Sorry guys, but I still can't see how this argument has any kind of weight. It's a great big universe, so clearly somewhere (or maybe in a few or even many places) conditions are going to be "just right" for life to arise.

You're still missing the point! These finely tuned conditions apply to the universe as a whole, not just in particular 'places' in the universe. For example, 2 finely tuned laws are the speed of light and the force of gravity - are the same everywhere in the universe (at least modern science assumes that they are). There's no pocket of the universe that has a different force of gravity! 

 Let me try to give you one example that should throw the argument into clear light. If the rate of expansion one second after the big bang had been smaller by even one part in a hundred thousand million million, the universe would have recollapsed before it ever reached its present size. 

So if the expansion rate of the universe were not finely tuned to within a hair's breadth, we wouldn't have a universe at all.  

Anonymous said...

As for the supposed vast "improbability" of the universe being as it is - that still gets a "meh" from me. Of course if the universe was just a bit different we (and galaxies, suns etc) wouldn't exist. But it wasn't.

Right, but you're still left with an incredible fact that you have left unexplained. The apparent fine tuning of the universe cries out for some kind of explanation. How foolish of us if, upon apprehending this fact, we merely shrug our shoulders and say 'well, that's just the way it is.'

Let me try a well known metaphor: Suppose you are facing a firing squad. Fifty marksmen take aim but they all miss. Of course if they hadn't all missed you wouldn't have survived to ponder the matter. That is a truism. But you wouldn't just shrug your shoulders with a "meh" and leave it at that – you'd be baffled, and would seek some further reason for your good fortune.

You guys are still doing your usual non sequitur act of tacking a quick "And so our particular deity was involed, the end" on the end of statements that simply don't lead to or require that conclusion.

No. The fine tuning argument does not point to any particular god any I've never seen anyone using the argument draw the conclusion that fine tuning shows [insert diety] exists.  At most it is an argument for deism.

Tim O'Neill said...

The apparent fine tuning of the universe cries out for some kind of explanation.

No, actually, it doesn't. It's just how it is.

How foolish of us if, upon apprehending this fact, we merely shrug our shoulders and say 'well, that's just the way it is.'

That's not "foolish" at all. "Foolish" is positing deities and invoking magic to "explain" something about the universe that just is.

At best it's little more than another "God of the gaps" argument, though it's barely even that. Yes, if the universe was slightly different we wouldn't be here nor would most other things that make up our universe. But it wasn't and so we are here. No gods are required or even strongly implied in all this.

Unless you believed in them in the first place, of course.

Anonymous said...

Good article by agnostic physicist Martin Rees on fine tuning of 6 numbers in the constants of physical laws (there are dozens more):

http://www.firstscience.com/site/articles/rees.asp

Remember, the *fact* of fine tuning has nothing to do with theism. Atheists like Stephen Hawking agree the universe is apparently fine tuned for life.

The interesting question is: how do we explain this incredible fact?

Anonymous said...

That's not "foolish" at all. "Foolish" is positing deities and invoking magic to "explain" something about the universe that just is.

At best it's little more than another "God of the gaps" argument, though it's barely even that. Yes, if the universe was slightly different we wouldn't be here nor would most other things that make up our universe. But it wasn't and so we are here. No gods are required or even strongly implied in all this.


Do you have a plausible naturalistic explanation for us?

Or are you seriously trying to tell us that such an incredible and improbable (actually mathematically impossible) event doesn't need explaining? Like the guy who survived the firing squad and didn't wonder how it happened?!

I don't think anyone would buy that mate. ;)

Ignorance said...

At best it's little more than another "God of the gaps" argument, though it's barely even that. Yes, if the universe was slightly different we wouldn't be here nor would most other things that make up our universe. But it wasn't and so we are here. No gods are required or even strongly implied in all this.

Do you really think there is no explanation to be sought?

It is not a God of the gaps argument at all, since it is not the invocation of god to explain a natural phenomenon in the universe but the explanation of the properties of the universe, such as the various constants involved. Why these properties are what they are is a metaphysical question, not a scientific one.

It doesn't help much to point out that theists accept the argument because of their bias, because it could equally well be that atheists reject it on that ground.

Leonhard said...

I like the fine-tuning problem.

I think it helps to separate the coincidences into three categories.

Local coincidences: These are things like the existence of a moon at the proper distance. Presence of metals. A planet of roughly Earth size in the Goldilocks of a star, placed sufficiently far from the galactic center.

Global coincidences: These are things needed for life that obtain everywhere in the visible universe. The value of the fine-structure constant, entropy at the big bang (basically this is the arrow of time problem), strength of gravity, certain ratios between various particles and so on.

Extra coincidences: These are stuff not needed for life, but that seems present for no good reason. Like the example of a moon at a proper distance to give an eclipse. Anyone know of other examples?

The first problem I have is that we need to restrain ourselves to talk only about uncoupled coincidences, unless you want to get into really messy probability theory. For instance you could have that if coincidence A obtains, that it raises the chance of B and C obtaining by a large factor. If that's true then the odds of obtaining A, B and C, is not P(A)*P(B)*P(C), but might be much closer to just P(A). Most people who advance the fine-tuning problem usually assume that all of the local coincidences are completely independent of each other, though there's little reason to suspect this. The formation of the Moon happened in the same environment as the Earth arose in. Perhaps its sufficient to just ponder the rarity of environments roughly like the one Earth formed in. There's also no consensus on how the Moon formed, let alone how moons form in other planetary systems. Plus there's already some evidence that the formation of the moon wasn't as unlikely as you'd expect, nor does it seem as necessary as the Rare Earth hypothesis claims. (digging out the references, I know I've read the abstracts of these papers)

Then there's a problem with postulating coincidences that might not be problematic for the origin of complex. Already someone on this forum pointed out tidal waves... why should they be important? Because they were important for our history? That's a statistics of one. Assuming that the evolutionary history of our planet is the only way things could happen, is assuming way to much, and arguing that it couldn't have followed other pathways because one can't imagine other ways is a fallacy. Life developing without iron for instance is not unreasonable. Of course the kicker will be to explore other planetoids like Mars, Titan and Europa to see what (if any) kinds of life developed there. Then I think we'll be better suited to put stringer requirements on where life can arise.

That brings us to the global coincidences. Here again you need to uncouple the parameters you want to argue about. Martin Reese gets it down to 6 truly independent parameters, 5 if you discount the number specifying the dimensionality of the universe. There is a problem I wish I heard more discussion from theists. That's the problem of introducing a proper measure on some of the variables.

The problem is that some of the variables can take on values between zero and infinity. You can't assign equal probability to all the values as you'd typically do. There's no way of doing that and having the integral summing to 1. In other words you need to specify a distribution assigning probability to various infinitesimal slices along the range, such that it all integrates to one, otherwise talking about probability makes no more sense than dividing by zero. A Gaussian-distribution would be one out of an infinity of infinities of examples. Depending on which one you apply you get different answers.

The extra coincidences, might just be mundane random coincidences that we happen to notice.

Matko said...

At best it's little more than another "God of the gaps" argument, though it's barely even that. Yes, if the universe was slightly different we wouldn't be here nor would most other things that make up our universe. But it wasn't and so we are here. No gods are required or even strongly implied in all this.

John Leslie powderized this objection, also know as the weak anthropic principle, with a thought experiment:

"Suppose you are to be executed by a firing squad of 100 trained marksmen, all of them aiming rifles at your heart. You are blindfolded; the command is given; you hear the deafening roar of the rifles. And you observe that you are still alive. The 100 marksmen missed!"

Taking off the blindfold, you do not observe that you are dead. No surprise there: you could not observe that you are dead. Nonetheless, you should be astonished to observe that you are alive. The entire firing squad missed you altogether! Surprise at that extremely improbable fact is wholly justified - and that calls for an explanation. You would immediately suspect that they missed you on purpose, by design."

Matko said...

Another way of saying it is this: if someone won the national lottery ten times in a row, we're justified in believing that the result was rigged in that person's favor. The same thing applies to our universe's life permitting properties, where the probabilities are much high than in the case of winning a lottery. To deny it special pleading.

courtney said...

It may seem odd, but I find this subject interesting as someone who is involved in manufacturing.

We measure key dimensions on a sample of our components during our process and compare them to specification. There is always variation and we tend to say that the variation follows a normal (Gaussian) distribution centred on this specification and we would call this normal for our process. If we find a part too far from specification we reject it. However, a normal distribution should means that we are less and less likely to see components as their deviation from specification increases.

But we always have to consider that perhaps our process is not working as it should and that deviation from specification isn’t due to “normal distribution” but due to what we call a “special cause”. If there is a special cause in play we have to move quickly because we could have a major issue. But how do we know if its normal or indicative of special cause? And I guess this is a similar question to the subject discussed here regarding the anthropic principle.

And engineers use the standard deviation to make the decision. Traditionally the threshold was that outside 4 sigma we do not assume normal deviation – i.e. that there is a special cause in play. The reason for this is that according to the normal distribution we only expect to see 0.27% of components with dimensions beyond 4 sigma – i.e. if we do see a part at 4 sigma, it is 99.73% likely to be a special cause.

Now the traditional atheist argument , the puddle argument, is just that we find ourselves in an improbable situation because this is the way it is and we wouldn’t be here discussing the issue unless the improbable had occurred.

But this strikes me as being similar to a process engineer explaining away the discovery of a component well beyond 4 sigma as simply part of normal distribution, albeit towards the tales, and that it is not surprising that we found it because the process controls happen to be there to do just that.

I fancy that the process engineer would be taken seriously from an academic, perhaps scientific perspective. However, from an engineering point of view, he would be told to shut up and identify the special cause.

Of course, in terms of the improbability of us being here in the universe, a special cause need not necessarily mean God. It might simply mean that we are here because there exists something that actually makes it very probable we would be. Just as a damaged tool means that our 4 sigma component is actually very likely because our assumed normal distribution is not in play. But the fact remains, if we want to be consistent with the real world, we should be talking in terms of a special cause rather than simply assuming that improbable things happen.

Suburbanbanshee said...

What I find funny is that, if Carl Sagan intones something about how vastly improbable life is, it's scientific. But if a religious person says it, somehow it's not science anymore.

Leonhard said...

That's an ad hominem attack Suburbanbanshee. First of all there's no scientific consensus on anything regarding how frequently life occurs throughout the galaxy. Second of all whatever philosophical speculations to that effect are not based upon the words of Carl Sagan, neither directly nor indirectly, overtly or implicitly. At most you can argue that he used the Drake equation, and many others do as well, as a thought experiment. Or you can argue that some have found inspiration in what he's said. If they are then get to call that person a twat, but I havn't seen anyone here do anything like that.

The fine-tuning problem is recognized by most scientists as an interesting problem. I've outlined *some* problems with making such an argument: Isolating independent parameters and normalizing parameters that have an infinitely wide range, or just identifying unnescarry (for life) and arbitrary arangements as rare, without accounting for selection bias. This is what the author of the blogpost did.

The fine-tuning problem is scientific in the respect that the postulates that feeds into it comes from Science. What conclusions that can be drawn from it is typically non-scientific, because the conclusions usually can't be verified or dis-confirmed by empirical research. Not whether Carl Sagan had any word on it.

I think your post reflects more on your frustrations with Sagan (which I don't understand) than with a fair assessment on how Science and philosophy about life and cosmology is being carried, or possibly both.

Leonhard said...

Minor typing mistake:

If they are (basing their conclusions on his words) then (you) get to call that person a twat, but I havn't seen anyone here do anything like that.