Apologies for the blogging drought. More soon. I couldn’t help but comment on something in the news recently.
Doing the rounds this week is a Wall Street Journal article by Eric Metaxas titled “Science Increasingly Makes the Case for God“. A few thoughts.
“Today there are more than 200 known parameters necessary for a planet to support life—every single one of which must be perfectly met, or the whole thing falls apart.”
I’m really hoping that his reference for the “200” parameters isn’t Hugh Ross, whom I’ve commented on before. The fine-tuning of the universe for intelligent life is about the fundamental parameters of the laws of nature as we know them, and there are only about 30 of those. Also, exactly zero fine-tuning cases require a parameter to be “perfectly” anything. There is always a non-zero (if sometimes very small) life-permitting window.
The fine-tuning for planets is a bit of a non-starter. How many planets are there in the universe? We don’t know, because we don’t know how large the universe is. There is no reason to believe that the size of the observable universe is any indication of the size of the whole universe.
Without a massive planet like Jupiter nearby, whose gravity will draw away asteroids, a thousand times as many would hit Earth’s surface.
This turns out to be a bit of a myth, however widely reported. Jonathan Horner and Barrie Jones used a set of simulations to test this idea, but their results tended to show that the opposite might be true.
The fine-tuning necessary for life to exist on a planet is nothing compared with the fine-tuning required for the universe to exist at all.
Nothing in science explains why the universe exists at all, let alone fine-tuned values of constants. I’ve explained this before here and here. Fine-tuning for life to exist at all is, however, and interesting kind of fine-tuning. I think that’s what Metaxas is referring to.
Astrophysicists now know that the values of the four fundamental forces—gravity, the electromagnetic force, and the “strong” and “weak” nuclear forces—were determined less than one millionth of a second after the big bang.
Not really. This would be a prediction of a combination of inflationary theory and a grand unified theory. So … maybe, but not exactly the most settled physics. In any case, this is of little relevance to fine-tuning, unless you’ve got multiverse scenario in mind.
If the ratio between the nuclear strong force and the electromagnetic force had been off by the tiniest fraction of the tiniest fraction—by even one part in 100,000,000,000,000,000—then no stars could have ever formed at all.
OK. I have no idea where that number comes from. And I’ve written a review article on this field. A parameter cannot be fine-tuned to a greater degree than it has been measured – otherwise, the fine-tuning would constitute a more accurate measurement. The strength of the strong force is only known to about 2% (technically, strong coupling constant at mass scale of Z boson.)
In one of his books (“Other Universes”, I think), Paul Davies states that the weak force is fine-tuned to one part in 10^40 (or 10^100 in another of his books). This is a statement about the vacuum state of the Higgs field (electroweak). This is essentially the cosmological constant problem, put rather oddly.
Alternatively, Metaxas could be thinking of charge neutrality. If the universe were very slightly charged, electromagnetic forces would always win over gravity, so not stars, planets etc.
In any case, give a reference!
The annoying thing is that there are plenty of scientifically correct cases on which Metaxas could have based his claims. Whether it proves God is another question, but he could at least get the science right.
Enter Lawrence Krauss
In response to this article, Cosmologist Lawrence Krauss wrote a letter to the editor. He didn’t do much better than Metaxas.
We currently DO NOT know the factors that allow the evolution of life in the Universe. … The mistake made by the author is akin to saying that if one looks at all the factors in my life that led directly to my sitting at my computer to write this, one would obtain a probability so small as to conclude that it is impossible that anyone else could ever sit down to compose a letter to the WSJ.
Conflates “we don’t know everything” with “we don’t know anything”. There are clear fine-tuning cases. With a relatively small tweak to the cosmological constant or the quark masses, we can make universes with no atoms, or one hydrogen atom per observable universe, or that last only a fraction of a second before recollapsing. In these cases, the details of which chemical reactions first formed life on Earth aren’t particularly relevant. We know enough, even if there is a lot more we’d like to know about life.
The “sitting at my computer” analogy is anything but apt. When does a small likelihood punish a theory sufficiently that an alternative theory should be preferred? Go use Bayes’s Theorem! This part of Metaxas argument is actually valid – if the premises are true, an interesting conclusion follows. (Make sure you understand the difference between valid and true before commenting on that sentence.)
We have discovered many more planets around stars in our galaxy than we previously imagined.
Relevant to fine-tuning for planets, but not for life at all. This is why Metaxas discussion of planets is a non-starter.
The Universe would certainly continue to exist even if the strength of the four known forces was different. It is true that if the forces had vastly different strengths (nowhere near as tiny as the fine-scale variation asserted by the writer) then life as we know it would probably not evolved.
Again, the force strengths have nothing to do with the existence of the universe. But Krauss’s statement that the force strengths could be “vastly different” contradicts most of the literature and is completely indefensible. See Figure 6 of my paper.
This is more likely an example of life being fine-tuned for the universe in which it evolved, rather than the other way around.
Again, a statement without justification in the scientific literature, unless Krauss is referring to a multiverse.
It’s annoying that both “sides” get the science wrong. Someone should set them straight. Perhaps someone should write a popular-level book on fine-tuning. With an astronomy professor. Perhaps a draft is nearly done …
I’d buy that book!!
Perhaps Metaxas should have referenced Ward & Brownlee, updated slightly here.
Oh that would be so good if you were to write a book for layman on these issues. I would read it! Something that gets into the details of a few cases and explains WHY any changes to the settings causes problems. (like the strong force and no hydrogen / all hydrogen).
In fact, I would like an introductory book on the evidence for the Big Bang, since I am still stuck using the 2nd edition of Robert Jastrow’s “God and the Astronomers”.
Looking forward to your book. I hope I can finally see some justification for (a) why you think the fundamental constants are tweakable to begin with (b) your specific choice for the distribution of their values and why it is the right one (c) reasons to be believe the constants are independent variables. Oh, and most importantly — your calculation showing that all alternative life arrangements, like Conway’s Game of Life, are so vastly improbable.
a) Chapter 1
b) Chapter 7
c) Chapter 7
d) Chapter 6
Great, I’ll look forward to it!
I’ve always found this whole laws and constants argument weird. So we tweak around the proportions between the strong and weak force, or gravity and electromagnetism (or whatever you want) and we get universes with a single hydrogen atom, or universes with no stars or planets but a dilute gaseous phase covering the cosmos etc.
Okay. But one thing is to talk about how adjusting the laws and constants we know about, another is postulating entirely new sets of laws and constants in addition to the ones we know.
For example, we know of four fundamental forces right? Suppose there’s a universe with 10, or 100, or a million, all interacting in their own way with different entities? How the heck are we in any position to say there’s only “our” set of four forces, “our” laws and “our” constants to tweak up and down?
Can any one point me to where it was worked out that a universe with 42 different fundamental forces and maybe 65 fundamental particles can in no way produce something reminiscent of life? Or that such a universe cannot even exist?
What justifies the assumption that “our” set of constants will be present in every universe and that the only thing that changes is the magnitude of it?
@Mikkel “Rumraket” Rasmussen I think you make an interesting point. There is no way to know what a universe would look like if it had a different set of fundamental laws. We can only know about universes with our set of laws, and we can see what would happen if we adjust the constants and ratios of those laws we know about.
So no one will write about what a universe with a completely different set of laws looks like, because it could literally be anything.
That’s why the discussion only revolves around what we know, not what we don’t know.
But in order for this line of reasoning to work, you must also posit a multiverse in which not only are the constants and quantities of our laws being distributed amongst the possible values, but the laws themselves are different too.
This is of course before we start questioning why we think life is the object of fine tuning in the first place. Most of these conditions required for life-constants that make us think the universe has been fine-tuned are relevant to carbon-chemistry, right? And life as we know it seems intrinsically tied to carbon chemistry as we know it.
But many things are dependent on carbon being the way it is, not just life. Why isn’t the universe fine-tuned to make carbondioxide, or thioesthers or pyruvate?
Its important to understand that, first, that the Universe is fine tuned to Exist itself.
Regardless of life or not its essentially an impossible structure When you see the trajectories it had to take to stand as a structure. This all has to do with the initial conditions prior to the big bang. To have a stable manifold and then also have stars , galaxies, and planets is enough to say the universe is fine tuned to have planets.
But are planets the ultimate objects of our reality.? If the DNA Molecule were the end product , an outside observer might say its FTuned for this virtually impossible molecule. But its concious embodied Observers that ultimately are the pinnacle of creation-so its most correct to use the Ultimate object in existence– which of course completely contradicts and is the ultimate defeater of the atheist mantra that we are insignificant nobody’s on an ordinary planet etc etc….hence, we put our foot in mouths proclaiming the parameters to a stable UV & life were wide but the data has proved precisely the opposite. Ha, it poetic.
Enter Multiverse. Just embarrassing.
I rarely buy books. But if you write one, I’d definitely wanna read it. I’m so glad you’re finally doing it!
[…] Barnes of the Sydney Institute of Astronomy (University of Sydney), who, in a blog article titled, Comment on “Science Increasingly Makes the Case for God”, excoriates Krauss’s letter to the editor of the Wall Street Journal (December 26, 2014), […]
Can you provide an estimated time frame in which your book will be available? I am really looking forward to reading it. Thank you for your work.
Meeting a publisher this afternoon.
Which evidence *about* God is your book going to discuss? What is the proposed title? Your thesis?
It’s going to discuss (mostly) the science of fine-tuning. Title undecided. The last chapter is a discussion of the various conclusions one might try to draw from fine-tuning. Stay tuned.
Is there any chance you will discuss Jonathan Weisberg objection which can be found in his article: The argument from divine indifference (link: http://www.utm.utoronto.ca/~weisber3/new/Research_files/TAfDI.pdf )
I know your book is mainly about the science of fine-tuning but I know you’ve also defended some claims that fine-tuning might be evidence of design. Weisberg argues that learning:
“S: the fact that the laws of our universe are stringent, i.e. that they will only support intelligent life on a few settings of the constants and initial conditions (this would be equivalent to your. “F” i think)
.. may amplify the evidential support O (where: O stands for the fact that life exists) lends to D (design), this does not mean that learning S in addition to O increases the net support for D. For S may simultaneously be evidence against D, so that the amplification of O’s support is drowned out by the disconfirmation effected by S.”
Any thoughts?
“Letting O be the old news that life exists”. Groan. https://letterstonature.wordpress.com/2013/11/17/bayes-theorem-what-is-this-background-information/
“Prior” information is just a label. It does not have to be the information you learned first, or tautological information, or background information. The paper, and the one it is responding to, have a lot of their probabilities backwards.
The fundamental confusion is in the figure on page 3. The possible set of universes considered by fine-tuning includes laws and constants. Fine-tuning is not merely the discovery that the laws of out universe are “stringent” – that they “will only support intelligent life on a few setting of the constants and initial conditions”. Most changes in the laws also seem to produce stringent laws. We don’t know of any “lax” laws.
And in any case, all these changes go into the one big possibility space, in which life-permitting universes are fine-tuned. It is simply not true that a typical life permitting universe could be expected to obey “lax” laws.
Oooo…you mean like now – where chemistry can be done by theoretical physicists a priori?.
If you can’t do high temperature superconductor physics a priori with the constants we have now
what make you think your speculations about all possible biologies using different constants are worth anything?
[…] times. The Drake Equation has been formulated to express this in quasi-scientific terms. Further, it can be argued that we don’t know how big the universe is, so there may well be many more potentially […]
Luke, I just finished A Fortunate Universe (like ten minutes ago). I thoroughly enjoyed the book. I particularly appreciated the back and forth on the G word. I might be inclined to add a couple of thoughts:
1. If there is a God, I suspect that God is way to smart to leave “fingerprints. Even if we are able to puzzle out the ultimate laws of nature, it isn’t clear to me (but then, I’m only an engineer) that such a condition precludes the existence of God since God is completely outside the universe and what we call reality. This gets into discussions that make my brain hurt.
2. This gets to the free will discussion (a condition that Dr. Gell-Mann would argue doesn’t exist – for what that’s worth. I think he’s swimming out of his lane). If we could prove that God exists then that knowledge might constrain our free will (how can you not love and obey an entity that is absolutely and compellingly lovable?).
In any event, I enjoyed your book.
Guy Higgins