I view that in the vein of planet formation. There are probably just as many possible outcomes for solar systems, a small fraction of which could support life. Does this mean we throw out the concept of solar system formation? I don’t think so.
But as I mentioned before, theoretical physics isn’t my strong suit so I will not comment on the specifics. However, String Theory did produce one of my favorite quotes:
“It’s not even wrong!”–Wolfang Pauli
Who said physicists can’t be snarky?
Very interesting links and posts, and understandable to a layman such as I, thanks.
The latter question seems like the controlling one to me. Fretting about the former almost seems like a “deck chair on the Queen Mary” in comparison.
Given that matter exists, as we learn more about the laws and constants behind it, it would be exceedingly strange if we discovered that they were not entirely conducive to its existence–and the deeper we go, not apparently finely tuned to it.
We’re still left with the old question of why anything is here at all! It would indeed be very interesting to understand conclusively that dials had been turned to set things just right. But it wouldn’t begin to answer the larger question. And I’m not sure we’re any closer to a falsifiable test for such a notion than to perhaps perceiving other universes and proving a multiverse (or a lack of one for that matter) either.
I read up a bit earlier. How did the idea of the multiverse first come about? I get the impression that it was an idea that was created on its own merits and not as any kind of response to the issue of apparent fine-tuning, though it now does seem to get referred to in such conversations often.
Hi John,
Thanks for your great post and questions!
The multiverse arises from two other concepts which could “predict” it: eternal inflation and the “string landscape” in String Theory.
Problem is, eternal inflation is a contested interpretation of inflationary theory (which itself is contested, including by one of the scientists who thought it up), there is the alternative of chaotic inflation, which does not produce the kind of multiverse that has the different physical constants.
But inflation itself was thought up to solve two fine-tuning problems: especially the “flatness” of the universe. So all roads do lead back to the accursed fine tuning.
And sadly, cosmic inflation has produced in turn new fine-tuning. It’s a nightmare, really.
Here is the verdict from Paul Steinhardt, one of three scientists who thought up the “inflationary multiverse” hypothesis in the 1980s (but who has since turned against it and is far more critical of the idea than I am, denying that it is even “explanatory”):
"…Physicist Slams Cosmic Theory He Helped Conceive
Paul Steinhardt, Albert Einstein Professor in Science and Director of the Center for Theoretical Science at Princeton University
Steinhardt: From the very beginning, even as I was writing my first paper on inflation in 1982, I was concerned that the inflationary picture only works if you finely tune the constants that control the inflationary period. Andy Albrecht and I (and, independently, Andrei Linde) had just discovered the way of having an extended period of inflation end in a graceful exit to a universe filled with hot matter and radiation, the paradigm for all inflationary models since. But the exit came at a cost – fine-tuning. The whole point of inflation was to get rid of fine-tuning – to explain features of the original big bang model that must be fine-tuned to match observations. The fact that we had to introduce one fine-tuning to remove another was worrisome. This problem has never been resolved…
I have to admit that I did not take the multiverse problem seriously at first even though I had been involved in uncovering it. I thought someone would figure out a resolution once the problem was revealed. That was 1983. I was wrong.
To me, the accidental universe idea (the notion that the features of the observable universe are accidental: consequences of living in this particular region of the multiverse rather than another), is scientifically meaningless because it explains nothing and predicts nothing. Also, it misses the most salient fact we have learned about large-scale structure of the universe: its extraordinary simplicity when averaged over large scales. In order to explain the one simple universe we can see, the inflationary multiverse and accidental universe hypotheses posit an infinite variety of universes with arbitrary amounts of complexity that we cannot see. Variations on the accidental universe, such as those employing the anthropic principle, do nothing to help the situation.
Scientific ideas should be simple, explanatory, predictive. The inflationary multiverse as currently understood appears to have none of those properties.…"
So, in short: cosmic inflation was proposed to deal with two kinds of fine-tuning; it led to the eternal inflation interpretation and this was then rolled into an attempt at a GUT (grand unified theory) otherwise known as String Theory, that attempted to square general relativity with quantum mechanics and led to the M-Theory “string landscape” idea that theorists reasoned could possibly result in the kind of multiverse which might solve the deeper fine-tuning problems at the heart of physics, especially the CC. Lovely, if only it were true and testable but alas 40 years has produced the grand total of…zero testable predictions and not even any testable consequences to speak of. Ever watched what happens when you remove one card from a “house of cards” decked high? Ahem.
You get the complicated picture, I hope!
Steinhardt now calls it “the multimess theory of anything”, which is pretty embarrassing given that he was one of the first people to conceptualize the eternal inflationary multiverse which he now savagely assaults for being “scientifically meaningless”.
I am a bit more respectful of the inflationary multiverse idea myself. I think it may have explanatory power but I certainly agree with him that its untestable and is not predictive. But its partly Steinhardt’s “baby”, so I am inclined to trust him on that front.
Not just billions of planets… but 2 trillion galaxies! A nice 2010 paper estimated there are 45.5 billion exoplanets in the Milky Way Galaxy alone. It might be different since then, but this doesn’t even include any satellites or moons around exoplanets.
And the matter of finding any life elsewhere… let’s say we’ve had radio technology for 100 years (not an actual figure), the best case scenario is a signal was sent 100 light years away. At best that signal has traveled to 0.000006% of the volume of the Milky Way Galaxy. And then we’d have to wait another amount of time to get a signal back, assuming any life has similar technology to send such a signal back. Nevermind the other 2 trillion galaxies.
Actually, there is no evidence for any universe but our own.
The multiverse is an extrapolation from other frameworks (namely eternal inflation and the string landscape) that have produced no unassailable, testable predictions despite being studiously analysed by the greatest minds working at the cutting-edge of theoretical physics for 40 years and accounting for about 90% of papers in that time.
Many folks don’t want to abandon the inflationary multiverse because (a) even though its not strictly speaking science, its at least philosophically plausible (b) it would solve otherwise intractable fine-tuning problems and (c) they don’t want to close the book on 40 years worthy of costly, fruitless endeavour and start again from scratch.
Most physicists, it should be said, would much rather be able to accurately calculate the observed value of the CC from first principles, thereby satisfying “naturalness”, rather than being compelled to invoke an infinity of undetectable and accidental universes immune to testability, which relegates the value of this parameter (and the other fine-tunings) to probable luck rather than physical necessity. Steven Weinberg has said this many times.
They just don’t see an alternative working from first principles but the problem is that the multiverse also requires the string landscape in M-Theory, which requires string theory which also requires SUSY and there is no evidence for SUSY/string theory. No extra hidden particles, superstrings or hidden dimensions have or are likely going to be discovered. I would be flabbergasted if we saw a Nobel Prize for String Theory by 2020, as Michio Kaku once predicted. I think that prediction at least is going to be falsified. At least it was “wrong”.
So they are in a real bind at the minute. As Professor Steven Weinberg himself explained in an interview only last month:
"…Unlike many particle physicists on the day of the Higgs announcement on 4 July 2012, Weinberg doesn’t recall exactly what he was doing when he heard the news. What he is sure of is that we are entering what he described several years ago as the “nightmare scenario” of having found a SM Higgs boson and nothing else.
He says we’ve gotten ourselves into a rather unfortunate situation because the SM describes all the physics that can be addressed experimentally except things outside the SM like gravity and the neutrino masses. “It’s nobody’s fault. It is not an intellectual failure. It’s just a fix we’ve got into.”
He doesn’t hold out too much hope in mainstream theoretical arguments for the existence of physics beyond the SM at the energies currently being probed at the LHC – i.e. that new heavy particles must exist to cancel out quantum contributions to the Higgs mass that would cause it to spiral to infinity. The fact that we now know that an elementary Higgs scalar exists makes this “hierarchy problem” somewhat harder, Weinberg concedes, but he points out that we’ve been living with the problem already for 40 years.
So far the LHC has not found evidence for physics beyond the SM, including the most popular solution to shield the Higgs from getting additional mass: supersymmetry (SUSY). “Worse, there isn’t any one completely satisfactory SUSY model. Every SUSY model has things in it that are troublesome,” says Weinberg.
He thinks we might have to find other explanations for this and other absurdly fine-tuned parameters in the universe, such as the very small value of the vacuum energy or cosmological constant, or even abandon traditional explanations altogether.
“No one has come up with a plausible suggestion there except for the somewhat desperate suggestion that it is anthropic – that you have a multiverse and by accident there are occasional sub-universes where the vacuum energy is small and it’s only those in which galaxies can form – and people have suggested similar anthropic arguments for the smallness of the Higgs mass and the quark-mass hierarchy,” says Weinberg, who himself used anthropic reasoning in the 1980s to estimate, correctly, the approximate value of the cosmological constant a decade before it was inferred observationally from the velocities of distant supernovae. It’s a depressing kind of solution to the problem, he accepts. “But as I’ve said: there are many conditions that we impose on the laws of nature such as logical consistency, but we don’t have the right to impose the condition that the laws should be such that they make us happy!”…"
Certainly more than I did 
Thanks for the explanation and the link!
It feels like you’ve been reading too much Steinhardt and other bounce cosmologists 
I think a nice summary for those who want to get caught up on the topic of the multiverse is this counter rebuttal to arguments like yours here Colin:
And a writeup on Carroll’s blog that I also found interesting:
http://www.preposterousuniverse.com/blog/2017/05/10/is-inflationary-cosmology-science/
Thanks Matthew, your links will certainly be useful to readers.
I should note, however, that I’ve referenced many folks above who are not “big bounce” cosmology fanboys, including the likes of Peter Woit, Joseph Silk, Weinberg himself, Nima Arkani-Hamed, George Ellis et al. I could also have referenced Lee Smolin, Carlo Rovelli, Paul Davies, Sabine Hossenfelder and many others. 
(I would add Sir Roger Penrose to the list but he is actually a bounce proponent, according to his latest book Fashion, Faith and Fantasy.) Many of these theorists (excepting Weinberg and Hamed) are intensely critical of the multiverse and string theory (as well as eternal inflation, in some cases) but are not supporters of a bounce cosmology.
There are alternatives like loop gravity and other ideas (Arkani-Hamed is now theorizing one the name of which I just can’t recall).
This is a much wider debate than “big bounce vs inflationary multiverse” and even physicists like Weinberg and Arkani-Hamed who have or do support the multiverse/string theory are now admitting its failures and suggesting other viable pathways to untie the gordian knot.
The 33 scientists referenced in that article signed on solely in response to Steinhardt and co.'s criticism of inflation, I do believe - not the inflationary multiverse and string theory. Not all of the signatories support these concepts but they do support some variant of inflation but - and this is important to stress - not all inflation theories lead to a multiverse or String landscape either, as I’ve already stated. Also Steinhardt and co. issued a reply to the aforementioned letter:
http://physics.princeton.edu/~cosmo/sciam/
Woit (who is critical of both the multiverse and bounce cosmology but does tend to support some variant of cosmic inflation) also commented on the rebuttal letter you reference above, as follows:
http://www.math.columbia.edu/~woit/wordpress/?p=9349
"…The article is subtitled “Why the majority of physicists are on one side of a recent exchange of letters”. One way to interpret this claim is just that 33 is more than 3, but the reason for this is clear: while Guth, Kaiser, Linde and Nomura decided to go on a political campaign, drumming up signatures on their letter, Ijjas, Loeb and Steinhardt didn’t do this, but instead put together a website discussing the scientific issues.
Where the majority of physicists stand on the Guth-Linde claims is an interesting question, one that I don’t think is addressed anywhere by hard numbers. My anecdotal data is that the majority of those I’ve ever talked to about this don’t think the Guth-Linde multiverse claims are science, but don’t see any reason to waste their time arguing with pseudo-science. They hope it will just go away by itself, as it becomes ever clearer that the multiverse is, scientifically, an empty idea…"
Also, Sean Carroll whose blog you link to in the above, is very much pro-multiverse and an interesting case. He published an article in 2014 in Edge magazine where he takes aim at those whom he deems “the Popperazi” (a neologism comprised of ‘Popper,’ as in Karl Popper the science philosopher who pioneered the theory of falsifiability and ‘Nazi’) and their inconvenient demands for falsifiable scientific predictions (or as he puts it himself: “somber pronouncements about non-falsifiability from fuddy-duddies”):
https://www.edge.org/annual-question/what-scientific-idea-is-ready-for-retirement
"…2014 : WHAT SCIENTIFIC IDEA IS READY FOR RETIREMENT?
Sean Carroll
Theoretical Physicist, Caltech; Author, The Big Picture
Falsifiability
"…Modern physics stretches into realms far removed from everyday experience, and sometimes the connection to experiment becomes tenuous at best. String theory and other approaches to quantum gravity involve phenomena that are likely to manifest themselves only at energies enormously higher than anything we have access to here on Earth. The cosmological multiverse and the many-worlds interpretation of quantum mechanics posit other realms that are impossible for us to access directly. Some scientists, leaning on Popper, have suggested that these theories are non-scientific because they are not falsifiable.
The truth is the opposite. Whether or not we can observe them directly, the entities involved in these theories are either real or they are not. Refusing to contemplate their possible existence on the grounds of some a priori principle, even though they might play a crucial role in how the world works, is as non-scientific as it gets.
The falsifiability criterion gestures toward something true and important about science, but it is a blunt instrument in a situation that calls for subtlety and precision…String theory says that, in certain regions of parameter space, ordinary particles behave as loops or segments of one-dimensional strings. The relevant parameter space might be inaccessible to us, but it is part of the theory that cannot be avoided. In the cosmological multiverse, regions unlike our own are unambiguously there, even if we can’t reach them. This is what distinguishes these theories from the approaches Popper was trying to classify as non-scientific.
It’s the “empirical” criterion that requires some care. At face value it might be mistaken for “makes falsifiable predictions.” But in the real world, the interplay between theory and experiment isn’t so cut and dried. A scientific theory is ultimately judged by its ability to account for the data—but the steps along the way to that accounting can be quite indirect.
Consider the multiverse. It is often invoked as a potential solution to some of the fine-tuning problems of contemporary cosmology. For example, we believe there is a small but nonzero vacuum energy inherent in empty space itself. This is the leading theory to explain the observed acceleration of the universe, for which the 2011 Nobel Prize was awarded. The problem for theorists is not that vacuum energy is hard to explain; it’s that the predicted value is enormously larger than what we observe.
If the universe we see around us is the only one there is, the vacuum energy is a unique constant of nature, and we are faced with the problem of explaining it. If, on the other hand, we live in a multiverse, the vacuum energy could be completely different in different regions, and an explanation suggests itself immediately…
In complicated situations, fortune-cookie-sized mottos like “theories should be falsifiable” are no substitute for careful thinking about how science works. Fortunately, science marches on, largely heedless of amateur philosophizing…"
Here’s his words above with only a few point modifications, to illustrate how a Theist might argue using similar logic to Professor Carroll:
“Some scientists, leaning on Popper, have suggested that these theories [about a Theistic Fine-Tuning God] are non-scientific because they are not falsifiable.
The truth is the opposite. Whether or not we can observe Him directly, the Creator involved in this theory is either real or He is not. Refusing to contemplate His possible existence on the grounds of some a priori principle, even though He might play a crucial role in how the world works, is as non-scientific as it gets.
It’s the “empirical” criterion that requires some care. At face value it might be mistaken for “makes falsifiable predictions.” But in the real world, the interplay between theory and experiment isn’t so cut and dried. A scientific theory is ultimately judged by its ability to account for the data—but the steps along the way to that accounting can be quite indirect.
The Creator might be inaccessible to us, but He is part of the theory that cannot be avoided”
I believe, apparently contrary to Professor Carroll and his hypothetical parallel universe theistic twin, that rigorous science should involve falsifiable hypotheses—ones that can be confirmed or disproved by data.
And for good measure, see also this essay in NATURE penned in response to Carroll’s Edge article by two of the world’s most prominent and respected cosmologists: Joe Silk and George Ellis. They are clear about what should be regarded as outside the bounds of science (and neither of them are bounce cosmologist, so far as I know):
https://www.nature.com/news/scientific-method-defend-the-integrity-of-physics-1.16535
"…Scientific method: Defend the integrity of physics
Scientific method: Defend the integrity of physics
16 December 2014
Attempts to exempt speculative theories of the Universe from experimental verification undermine science, argue George Ellis and Joe Silk.
This year, debates in physics circles took a worrying turn. Faced with difficulties in applying fundamental theories to the observed Universe, some researchers called for a change in how theoretical physics is done. They began to argue — explicitly — that if a theory is sufficiently elegant and explanatory, it need not be tested experimentally, breaking with centuries of philosophical tradition of defining scientific knowledge as empirical. We disagree. As the philosopher of science Karl Popper argued: a theory must be falsifiable to be scientific.
Chief among the ‘elegance will suffice’ advocates are some string theorists. Because string theory is supposedly the ‘only game in town’ capable of unifying the four fundamental forces, they believe that it must contain a grain of truth even though it relies on extra dimensions that we can never observe. Some cosmologists, too, are seeking to abandon experimental verification of grand hypotheses that invoke imperceptible domains …
These unprovable hypotheses are quite different from those that relate directly to the real world and that are testable through observations — such as the standard model of particle physics and the existence of dark matter and dark energy.
The issue of testability has been lurking for a decade. String theory and multiverse theory have been criticized in popular books1, 2, 3 and articles, including some by one of us (G.E.)4. In March, theorist Paul Steinhardt wrote5 in this journal that the theory of inflationary cosmology is no longer scientific because it is so flexible that it can accommodate any observational result. Theorist and philosopher Richard Dawid6 and cosmologist Sean Carroll7 have countered those criticisms with a philosophical case to weaken the testability requirement for fundamental physics.
MANY MULTIVERSES
The multiverse is motivated by a puzzle: why fundamental constants of nature, such as the fine structure constant that characterizes the strength of electromagnetic interactions between particles and the cosmological constant associated with the acceleration of the expansion of the Universe, have values that lie in the small range that allows life to exist. Multiverse theory claims that there are billions of unobservable sister universes out there in which all possible values of these constants can occur. So somewhere there will be a biofriendly universe like ours, however improbable that is. Some physicists consider that the multiverse has no challenger as an explanation of many otherwise bizarre coincidences. The low value of the cosmological constant — known to be 120 factors of 10 smaller than the value predicted by quantum field theory — is difficult to explain, for instance. …
… [Sean Carroll] argues that inaccessible domains can have a “dramatic effect” in our cosmic back yard, explaining why the cosmological constant is so small in the part we see. But in multiverse theory, that explanation could be given no matter what astronomers observe. All possible combinations of cosmological parameters would exist somewhere, and the theory has many variables that can be tweaked.
The consequences of overclaiming the significance of certain theories are profound — the scientific method is at stake (see What is science and why should we care? — Part I | Scientia Salon). To state that a theory is so good that its existence supplants the need for data and testing in our opinion risks misleading students and the public as to how science should be done and could open the door for pseudoscientists to claim that their ideas meet similar requirements…"
But, I am very grateful for your links to round the circle!
How is Fine Tuning any different from Douglas Adams puddle argument?
Only in those universes where things were balanced appropriately would there be planets … and thus would there be living creatures marveling at the existence of planets.
The Fine Tuning argument is an aesthetic evidence… sometimes very potently characterizied. But… it is not any kind of proof.
I do not then k that Fine Tuning is based on aesthetic evidence. What I see it saying is that the universe is relational. It is based a large number of interdependent relationships, and if you change one then the whole character of the universe is radically changed.
If this is true. and I do not see any evidence that it is not, then this means that the universe is not only relational, but rational, and if rational, then rationally structured or designed. This means that things do not happen as the result of only chance, but because the universe is governed by rational laws. Even if something appears to us to happen by chance, an accident, it is still governed by the law of gravity, etc.
Sadly because evolutionists wanted to refute Paley’s argument that the universe is created and designed as a watch if created and designed, “intelligent design” has a bad rep. Part of the problem is that Creationists believed that God did not create by evolution, but argue3d that God created different “kinds” of life de novo, which is false.
Another problem is the insistence by Darwin and Dawkins evolution is not a rational process, but based on pure chance. This is not true. Evolution is based on Ecology which is another rational process Ecology demystifies Natural Selection and demonstrates the relational nature of the universe. When we accept the fact that Nature created through rational evolution and ecology, which are rational processes, these issues disappear.
The key question for me is the rationality of the universe. While it is true that I would think that the rationality of the universe is evidence for the existence of God, it also indicates that the universe has meaning and purpose. It means that it is intelligible, as Einstein said in the paraphrase, “The most unintelligible fact about the universe is that it is intelligible.”
If the universe is not intelligently structure, then science is a myth and everything we think and believe is false.
W
The puddle argument is a local argument. My little corner of the universe is perfect for me! It is stating something manifestly true given evolution. It is saying that we shouldn’t be surprised that earth is perfect for the kind of life we find on earth. It is a rather “duh” argument, and probably a good example as to why we should not look to comic science fiction writers for any substantive argument. Comedy yes, science no. Life on earth should never be surprised that the earth is perfect-- because evolution.
By contrast the fine tuning argument is global. It is not that it is surprising that the universe is perfect for life as we know it. It is is surprising that the universe is habitable for any type of life–because it is surprising the universe produces rocks. No rocks, no life.
Correct. None of this was really about empirical evidence (I didn’t think) … if it was, then that would be science. It is about people’s perceptions and interpretations of our sample size of 1 – whether we should be amazed by it or not, and is it an apologetic or not. What we all seem to agree on is that either way; this is all beyond evidence. We can pretend that some of it could eventually become scientific. We can wish for that and opine that it ought to be. But our reality here and now is that it isn’t. And here we are thinking about it anyway and knowing that with or without evidence, one of these choices is still true!
I can only loosely follow much of your astro- or particle-physics musings that are mostly above my pay grade. Sorry I won’t be able to hold up my end of a conversation on the details with you, but it sounds like we do agree on some of the big picture things --or so I guess, having not even fully read your all of your voluminous contributions above!
And all those universes that don’t have include the necessary criteria will not have any occupied planets to marvel over the perfect fit.
Are you following what I mean here?
I[quote=“gbrooks9, post:34, topic:36932”]
Are you following what I mean here?
[/quote]
I think I grasp the concept. In my opinion you are equating the anthropic principle with the privileged planet (or Adams’ puddle) argument. The former is a large numbers argument (and has nothing to do with evolution) and the latter is a consequence of evolution. One states that–given we are in a universe conducive for life, and if the habitability is sensitive to the constants, and the constants are a random draw, then there must be a multiverse (or god, or both). It says nothing about the type of life that might arise, or if indeed any arises. The latter says that if life arises (which the former doesn’t demand) then by evolution it will be perfectly suited for its environment. The former is profound, the latter sort of “duh.” The former “predicts” an incalculable and utterly small (but not zero) value for the cosmological constant–which requires an amazing set of near cancellations in a series. The latter predicts, as far as I can tell, nothing.
Anyone who argues that the fact the Universe, or the Solar System, or the Sun, or the Earth, has criteria that could have just as easily been against life, is using the principle of “co-incident” events as a proof. But all that such information can be used to do is appeal to humanity’s vanity.
Can an appeal to human vanity predict the value of the cosmological constant?
I was a little curious, so I took a bit of a look here. It’s interesting that in the posthumously published book where the quote appears, Adams didn’t use the argument in this way. It’s a simple analogy about the way people see the world and might have come up with the idea for God. In this talk he uses it as well, a little differently, including the idea as an explanation of why we may not always be inclined to protect the world as much as we should.
Other atheist writers and speakers have definitely seized upon it and used it in the way you suggest, and it has become well known in that context, to the extent that I noticed other criticism of Adams online for the usage. But Adams didn’t intend it in that way as far as I can see.
Hi John,
You may be right. It may be that it has been co-opted. It is true that I only come across it as an utterly naive dismissal of fine-tuning as a non-problem (when in fact, theological and philosophical implications be damned, it is a fascinating scientific puzzle.)
Douglas Adams, wherever you may be, if I mistakenly cast aspersions on your intent, I apologize from this side of the great divide.
Quantum laws are a part of our universe and they appear to be completely ruled by chance. How does that fit into your views?
For example, there is the double slit experiment where a single photon passes through two slits, interferes with itself, and lands in a pattern on a screen as governed by a probability. Where the photon lands is chance.
As we have already seen, the rational processes you point to are based on chance.[quote=“Relates, post:30, topic:36932”]
The key question for me is the rationality of the universe. While it is true that I would think that the rationality of the universe is evidence for the existence of God, it also indicates that the universe has meaning and purpose. It means that it is intelligible, as Einstein said in the paraphrase, “The most unintelligible fact about the universe is that it is intelligible.”
[/quote]
That seems like a leap in logic to me, but we already hashed that out in another thread so I will leave it there.
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