Fine-tuning: Is the universe finely tuned due to physical necessity ?

Is the universe finely tuned due to physical necessity ?

https://reasonandscience.catsboard.com/t1847-is-the-universe-finely-tuned-due-to-physical-necessity

A universe where these fundamental constants have different values is just as mathematically and logically consistent as our own. They represent other universes among the set of possible universes. Accordingly, these constants are considered free parameters.

Of the 30 known fundamental physical constants, very few of them can change to any significant degree without leading to a barren universe. For instance, universes of only hydrogen, universes with no aggregations of matter, or universes of only black holes.
https://alwaysasking.com/is-the-universe-fine-tuned/

Paul Davies: God and Design: The Teleological Argument and Modern Science page 148–49, 2003
“There is not a shred of evidence that the Universe is logically necessary. Indeed, as a theoretical physicist I find it rather easy to imagine alternative universes that are logically consistent, and therefore equal contenders of reality” 
https://3lib.net/book/733035/b853a0

Arbitrary Quantities
As for the arbitrary quantities, remember those are completely independent of the laws of nature – they are just put in as initial conditions on which the laws of nature then operate. Nothing seems to make these quantities necessary in the values they have. The opponent of design is taking a very radical line that would require some sort of evidence, some sort of proof. But there isn’t any proof that these constants and quantities are physically necessary. This alternative is just put forth as a bare possibility, and possibilities come cheap. What we are looking for is probabilities or plausibilities, and there just isn’t any evidence that the constants and quantities are physically necessary in the way that this alternative imagines.
http://www.firstthings.com/blogs/firstthoughts/2010/10/fine-tuning-an-argument-and-a-universe

Paul Davies:  Information, and the Nature of reality , page 86:
Given that the universe could be otherwise, in vastly many different ways, what is it that determines the way the universe actually is? Expressed differently, given the apparently limitless number of entities that can exist, who or what gets to decide what actually exists? The universe contains certain things: stars, planets, atoms, living organisms … Why do those things exist rather than others? Why not pulsating green jelly, or interwoven chains, or fractal hyperspheres? The same issue arises for the laws of physics. Why does gravity obey an inverse square law rather than an inverse cubed law? Why are there two varieties of electric charge rather than four, and three “flavors” of neutrino rather than seven? Even if we had a unified theory that connected all these facts, we would still be left with the puzzle of why that theory is “the chosen one.” "Each new universe is likely to have laws of physics that are completely different from our own."  If there are vast numbers of other universes, all with different properties, by pure odds at least one of them ought to have the right combination of conditions to bring forth stars, planets, and living things. “In some other universe, people there will see different laws of physics,” Linde says. “They will not see our universe. They will see only theirs. In 2000, new theoretical work threatened to unravel string theory. Joe Polchinski at the University of California at Santa Barbara and Raphael Bousso at the University of California at Berkeley calculated that the basic equations of string theory have an astronomical number of different possible solutions, perhaps as many as 10^1,000*.   Each solution represents a unique way to describe the universe. This meant that almost any experimental result would be consistent with string theory. When I ask Linde whether physicists will ever be able to prove that the multiverse is real, he has a simple answer. “Nothing else fits the data,” he tells me. “We don’t have any alternative explanation for the dark energy; we don’t have any alternative explanation for the smallness of the mass of the electron; we don’t have any alternative explanation for many properties of particles.
https://3lib.net/book/1021142/805fdd

The Degree of Fine-Tuning in our Universe – and Others
This paper reviews the current constraints on these quantities. The discussion starts with an assessment of the parameters that are allowed to vary.  
https://arxiv.org/pdf/1902.03928.pdf

D. HALSMER: THE COHERENCE OF AN ENGINEERED WORLD Volume 4 (2009)
Even if all constants in this universe were reduced to a single TOE with just one universal constant, there is no reason why another universe should obey the same TOE. Otherwise, one would have to explain the origin of the order given by the TOE. Others have recognized the inadequacy of such explanations and have actually proposed that universes with very different behavior may exist.
https://www.witpress.com/elibrary/dne-volumes/4/1/382

If the parameters are allowed to vary, there is no physical necessity.

Steven Weinberg:   Department of Physics, University of Texas
Anthropic Considerations
In several cosmological theories the observed big bang is just one member of an ensemble. The ensemble may consist of different expanding regions at different times and locations in the same spacetime,7 or of different terms in the wave function of the universe.8 If the vacuum energy density ρV varies among the different members of this ensemble, then the value observed by any species of astronomers will be conditioned by the necessity that this value of ρV should be suitable for the evolution of intelligent life. 5

The first option, physical necessity, is the easiest to dismiss. The idea that it was physically impossible for the universe to have been created in any way other than in a manner that would support life is neither logically necessary nor scientifically plausible. As Barr notes, “In the final analysis one cannot escape from two very basic facts: the laws of nature did not have to be as they are; and the laws of nature had to be very special in form if life were to be possible.” Our options, therefore, are between chance (the anthropic coincidences truly are coincidences) or design (the parameters needed for life were purposely arranged). While it cannot be established with absolute certainty, we can, I believe, determine that design is the most probable explanation.

Physical Necessity
First, let’s talk about physical necessity. As I just explained, according to this alternative the universe has to be life-permitting. The constants and the quantities had to have the values that they do. It is literally physically impossible for the universe to be life-prohibiting. It is physically necessary that the universe be a life-permitting universe. 1

String theory, the current best candidate for a "theory of everything," predicts an enormous ensemble, numbering 10 to the power 500 by one accounting, of parallel universes. Thus in such a large or even infinite ensemble, we should not be surprised to find ourselves in an exceedingly fine-tuned universe. [url=https://reasonandscience.catsboard.com/ https://phys.org/news/2014-04-science-philosophy-collide-fine-tuned-universe.html#jCp]3[/url]

Implausibility
On the very face of it, this is an extraordinarily implausible explanation of the fine tuning. It would require us to say that a life-prohibiting universe is physically impossible – such a thing could not exist. And that is an extremely radical view. Why take such a radical position? The constants, as we have seen, are not determined by the laws of nature. Nature’s laws could hold, and the constants could take any of a wide range of values, so there is nothing about the laws of nature that require the constants to have the values that they do.

What About God?
For many physicists, the multiverse remains a desperate measure, ruled out by the impossibility of confirmation. Critics see the anthropic principle as a step backward, a return to a human-centered way of looking at the universe that Copernicus discredited five centuries ago. They complain that using the anthropic principle to explain the properties of the universe is like saying that ships were created so that barnacles could stick to them.

“If you allow yourself to hypothesize an almost unlimited portfolio of different worlds, you can explain anything,” says John Polkinghorne, formerly a theoretical particle physicist at Cambridge University and, for the past 26 years, an ordained Anglican priest. If a theory allows anything to be possible, it explains nothing; a theory of anything is not the same as a theory of everything, he adds.

If the life-friendly fine-tuning of our universe is just a chance occurrence, something that inevitably arises in an endless array of universes, is there any need for a fine-tuner—for a god?

“I don’t think that the multiverse idea destroys the possibility of an intelligent, benevolent creator,” Weinberg says. “What it does is remove one of the arguments for it, just as Darwin’s theory of evolution made it unnecessary to appeal to a benevolent designer to understand how life developed with such remarkable abilities to survive and breed.”

” Carr says, “you might have to have a fine-tuner. If you don’t want God, you’d better have a multiverse.”

Cosmic Coincidences
If these cosmic traits were just slightly altered, life as we know it would be impossible. A few examples:

• Stars like the sun produce energy by fusing two hydrogen atoms into a single helium atom. During that reaction, 0.007 percent of the mass of the hydrogen atoms is converted into energy, via Einstein’s famous e = mc2 equation. But if that percentage were, say, 0.006 or 0.008, the universe would be far more hostile to life. The lower number would result in a universe filled only with hydrogen; the higher number would leave a universe with no hydrogen (and therefore no water) and no stars like the sun.

• The early universe was delicately poised between runaway expansion and terminal collapse. Had the universe contained much more matter, additional gravity would have made it implode. If it contained less, the universe would have expanded too quickly for galaxies to form.

• Had matter in the universe been more evenly distributed, it would not have clumped together to form galaxies. Had matter been clumpier, it would have condensed into black holes.

• Atomic nuclei are bound together by the so-called strong force. If that force were slightly more powerful, all the protons in the early universe would have paired off and there would be no hydrogen, which fuels long-lived stars. Water would not exist, nor would any known form of life. 2

John D. Barrow: Inconstant Constants Do the inner workings of nature change with time? February 1, 2006  6
Some things never change. Physicists call them the constants of nature. Such quantities as the velocity of light, c, Newton's constant of gravitation, G, and the mass of the electron, me, are assumed to be the same at all places and times in the universe. They form the scaffolding around which the theories of physics are erected, and they define the fabric of our universe. Physics has progressed by making ever more accurate measurements of their values.

And yet, remarkably, no one has ever successfully predicted or explained any of the constants. Physicists have no idea why constants take the special numerical values that they do (given the choice of units). In SI units, c is 299,792,458; G is 6.673 1011; and me is 9.10938188 1031--numbers that follow no discernible pattern. The only thread running through the values is that if many of them were even slightly different, complex atomic structures such as living beings would not be possible. The desire to explain the constants has been one of the driving forces behind efforts to develop a complete unified description of nature, or theory of everything. Physicists have hoped that such a theory would show that each of the constants of nature could have only one logically possible value. It would reveal an underlying order to the seeming arbitrariness of nature.

In recent years, however, the status of the constants has grown more muddled, not less. Researchers have found that the best candidate for a theory of everything, the variant of string theory called M-theory, is self-consistent only if the universe has more than four dimensions of space and time--as many as seven more. One implication is that the constants we observe may not, in fact, be the truly fundamental ones. Those live in the full higher-dimensional space, and we see only their three-dimensional shadows.

Meanwhile, physicists have also come to appreciate that the values of many of the constants may be the result of mere happenstance, acquired during random events and elementary particle processes early in the history of the universe. In fact, string theory allows for a vast number--10^500--of possible worlds with different self-consistent sets of laws and constants [see The String Theory Landscape, by Raphael Bousso and Joseph Polchinski; SCIENTIFIC AMERICAN, September 2004]. So far researchers have no idea why our combination was selected. Continued study may reduce the number of logically possible worlds to one, but we have to remain open to the unnerving possibility that our known universe is but one of many--a part of a multiverse--and that different parts of the multiverse exhibit different solutions to the theory, our observed laws of nature being merely one edition of many systems of local bylaws [see Parallel Universes, by Max Tegmark; SCIENTIFIC AMERICAN, May 2003].

No further explanation would then be possible for many of our numerical constants other than that they constitute a rare combination that permits consciousness to evolve. Our observable universe could be one of many isolated oases surrounded by an infinity of lifeless space--a surreal place where different forces of nature hold sway and particles such as electrons or structures such as carbon atoms and DNA molecules could be impossibilities. If you tried to venture into that outside world, you would cease to be.

Thus, string theory gives with the right hand and takes with the left. It was devised in part to explain the seemingly arbitrary values of the physical constants, and the basic equations of the theory contain few arbitrary parameters. Yet so far string theory offers no explanation for the observed values of the constants.

Uzan (2011), chapter 7: "Why Are The Constants Just So?":
"The numerical values of the fundamental constants are not determined by the laws of nature in which they appear. One can wonder why they have the values we observe. In particular, as pointed out by many authors, the constants of nature seem to be fine-tuned [Leslie (1989)]. Many physicists take this fine-tuning to be an explanandum that cries for an explanans, hence following Hoyle [(1965)] who wrote that 'one must at least have a modicum of curiosity about the strange dimensionless numbers that appear in physics.'"

Hamish Johnston: Changes spotted in fundamental constant 02 Sep 2010 https://physicsworld.com/a/changes-spotted-in-fundamental-constant/
Billions of years ago the strength of the electromagnetic interaction was different at opposite ends of universe. That’s the surprising conclusion of a group of physicists in Australia, who have studied light from ancient quasars. The researchers found that the fine-structure constant, known as α, has changed in both space and time since the Big Bang.

The fine-structure constant, about 1/137, is a measure of the strength of the electromagnetic interaction and quantifies how electrons bind within atoms and molecules. It is a dimensionless number, which makes it even more fundamental than other constants such as the strength of gravity, the speed of light or the charge on the electron.

J. K. Webb: Indications of a spatial variation of the fine structure constant 23 Aug 2010  
https://arxiv.org/pdf/1008.3907.pdf

Recent research also introduced the possibility that the constant has actually increased over the last six billion years, even though slightly.
https://www.physicscentral.com/explore/action/constant.cfm

The big baffling number at the heart of a cosmic coincidence
https://reasonandscience.catsboard.com/t2772-the-big-baffling-number-at-the-heart-of-a-cosmic-coincidence
Alpha is one of the fundamental constants in physics. If it had not the precise value that it has, there would be no life in the universe.

One of these fundamental constants is the fine-structure constant, or alpha, which is the coupling constant for the electromagnetic force and equal to about 1/137.0359. If alpha were just 4% bigger or smaller than it is, stars wouldn't be able to make carbon and oxygen, which would have made it impossible for life as we know it to exist.

The reason 137 has obsessed so many thinkers to try and find the math behind it is clear. Einstein wrote, “In a reasonable theory there are no numbers whose values are only empirically determinable.”

“It is impossible for human minds to construct something as infinitely rich as mathematics, that so successfully describes our universe down to the finest detail. Given that it is impossible for anything else to describe our world so accurately, it is also impossible to conclude that the universe is not mathematical.



1. http://www.reasonablefaith.org/defenders-2-podcast/transcript/s4-15#ixzz393jHbSUb
2. http://discovermagazine.com/2008/dec/10-sciences-alternative-to-an-intelligent-creator
3.  https://phys.org/news/2014-04-science-philosophy-collide-fine-tuned-universe.html#jCp
5. https://physicsworld.com/a/changes-spotted-in-fundamental-constant/
6. https://www.scientificamerican.com/article/inconstant-constants-2006-02/
7. https://physicsworld.com/a/changes-spotted-in-fundamental-constant/
8. https://arxiv.org/abs/1008.3907

Martin J. Rees: Fine-Tuning, Complexity, and Life in the Multiverse 2018
The physical processes that determine the properties of our everyday world, and of the wider cosmos, are determined by some key numbers: the ‘constants’ of micro-physics and the parameters that describe the expanding universe in which we have emerged. We identify various steps in the emergence of stars, planets and life that are dependent on these fundamental numbers, and explore how these steps might have been completely prevented — if the numbers were different.


What actually determines the values of those parameters is an open question.  But growing numbers of researchers are beginning to suspect that at least some parameters are in fact random variables, possibly taking different values in different members of a huge ensemble of universes — a multiverse.   At least a few of those constants of nature must be fine-tuned if life is to emerge. That is, relatively small changes in their values would have resulted in a universe in which there would be a blockage in one of the stages in emergent complexity that lead from a ‘big bang’ to atoms, stars, planets, biospheres, and eventually intelligent life. We can easily imagine laws that weren’t all that different from the ones that actually prevail, but which would have led to a rather boring universe — laws which led to a universe containing dark matter and no atoms; laws where you perhaps had hydrogen atoms but nothing more complicated, and therefore no chemistry (and no nuclear energy to keep the stars shining); laws where there was no gravity, or a universe where gravity was so strong that it crushed everything; or the cosmic lifetime was so short that there was no time for evolution; or the expansion was too fast to allow gravity to pull stars and galaxies together.

Fine-tuning - not due to physical necessity

The existence of stable atoms, stars, and life hinges upon an astonishing convergence of fundamental laws, forces, and constants in our universe. Remarkably, many of these properties appear to be precisely fine-tuned, not by any known deeper physical necessity or deeper grounding, but nonetheless by a precision that has allowed for the emergence of complex structures and life itself.

Strengths of fundamental forces: The strength of the strong nuclear force, which binds quarks together to form hadrons like protons and neutrons, is not derived from any known deeper principle. If this force were slightly weaker, atomic nuclei would not be stable, and if it were stronger, they would become intolerably massive, preventing the formation of complex elements essential for life chemistry.

The strength of the electromagnetic force, which governs the interactions between charged particles, is also not dictated by any fundamental physical necessity. A slight variation could either prevent the formation of stable atoms or render chemical reactions impossible, precluding the existence of complex molecules and life as we know it.
The strength of the weak nuclear force, responsible for certain radioactive decays and processes within stars, is not strictly constrained by any known theoretical principle. Deviations from its observed value could disrupt the delicate balance of nuclear processes that sustain stellar dynamics and the synthesis of heavier elements necessary for life.
The relative strengths of these fundamental forces are precisely balanced, enabling the intricate interplay of forces that shape the cosmos and allow for the existence of complex structures. Yet, there is no known deeper grounding that necessitates this specific balance.

Properties of fundamental particles: The masses of elementary particles like electrons and quarks are finely tuned within a narrow range suitable for the formation of atoms, nuclei, and the elements required for life chemistry. If these masses were significantly different, the particles we observe today might not have existed, or their interactions could have been vastly altered, rendering the universe inhospitable to life. There is no known deeper theoretical principle that strictly constrains or explains the observed values of these particle masses. No known principle or constraint strictly dictates the observed values of particle masses or prohibits them from having different masses altogether. The existence of different generations of particles with varying masses is a testament to the fact that their masses could, in principle, take on different values without violating any known laws of physics.

The observed masses of fundamental particles like electrons, quarks, and other subatomic constituents are empirical values that are not derived from deeper theoretical principles within the Standard Model of particle physics or any other well-established theory. There is no underlying theoretical framework or set of equations that necessitates these particles to have the specific masses we observe. The lack of a strict constraint or theoretical grounding for particle masses is evidenced by the following observations: The Standard Model comprises three generations of fundamental particles, including leptons (such as electrons and neutrinos) and quarks. Particles within each generation have different masses, and no known principle dictates or explains the specific mass differences between generations. The masses of composite particles, such as protons and neutrons, are not strictly determined by the masses of their constituent quarks. Instead, they arise from the complex dynamics of the strong nuclear force binding the quarks together, and there is no fundamental theory that precisely calculates or constrains these masses from first principles. While the Higgs mechanism in the Standard Model provides a way for particles to acquire mass through their interactions with the Higgs field, the specific values of the particle masses are not predicted by the theory itself. These values are treated as free parameters that must be determined experimentally. In various theoretical models and extensions of the Standard Model, such as supersymmetry or grand unified theories, the particle masses are often related to new hypothetical particles or fields. However, these models do not strictly constrain the masses to their observed values but rather introduce additional free parameters that need to be constrained by experimental data. The fact that particle masses can vary across different generations and that composite particle masses are not strictly determined by their constituents suggests that there is no fundamental physical necessity or constraint that dictates the specific values we observe. In principle, the particles could be composed of different subatomic constituents with different masses, as long as the resulting dynamics and interactions are consistent with experimental observations.

The electric charges of particles like protons and electrons are intrinsic properties that are not derived from any fundamental theory. If these charges were different, the entire landscape of electromagnetic interactions and the formation of stable atoms would be disrupted, eliminating the possibility of complex chemistry and life. The spin and statistical properties of particles, which determine whether they are classified as fermions or bosons, are empirical observations not derived from deeper theoretical principles. A universe dominated by only one type of particle would have vastly different dynamics and might not support the rich diversity of structures we observe.

Principles and constants: The very existence and validity of the principles of quantum mechanics, which govern the behavior of particles and fields at the subatomic scale, are not dictated by any known deeper physical necessity. A universe with different quantum principles could have radically different properties, potentially precluding the formation of stable atoms and molecules. The values of fundamental constants like the fine-structure constant (which characterizes the strength of the electromagnetic force) and the gravitational constant are finely tuned within a narrow range that allows for the existence of atoms, chemistry, and the gravitational dynamics that shape the cosmos. There is no known deeper physical reason that strictly defines or constrains these constants to have their observed values. The existence and properties of the Higgs field, which endows particles with mass, exhibit a surprising fine-tuning known as the "naturalness problem." Quantum corrections from other particles almost precisely cancel out to give the observed low Higgs mass, a phenomenon for which there is no known deeper theoretical explanation or physical necessity.

Properties of spacetime: The number of spatial dimensions in our universe (three) is an empirical observation not derived from any fundamental theory. A universe with a different number of dimensions would have radically different properties and dynamics, potentially precluding the formation of stable structures and life. The existence and properties of gravity, as described by Einstein's theory of general relativity, are not dictated by any known deeper physical necessity. A universe without gravity or with different gravitational dynamics could not sustain the large-scale structures and cosmic evolution that ultimately led to the formation of stars, galaxies, and the conditions necessary for life.

Initial conditions of the universe: The specific values of fundamental fields and their gradients in the early universe, which seeded the formation of structures and galaxies, are not derived from any known theoretical principle. Slight deviations in these initial conditions could have resulted in a universe devoid of the complexity and diversity we observe today. The matter-antimatter asymmetry, which resulted in the predominance of matter over antimatter in the observable universe, is an unexplained phenomenon not dictated by any known deeper physical necessity. A universe with equal amounts of matter and antimatter would have annihilated itself, preventing the formation of stable structures and life. The density fluctuations in the early universe, which acted as seeds for the formation of large-scale structures like galaxies and clusters, are not derived from any fundamental theory. Different initial fluctuations could have led to a vastly different cosmic structure and evolution, potentially precluding the formation of stars and the conditions necessary for life. The initial temperature of the early universe for example is a "free parameter" not constrained by any known fundamental physical principle. It could have taken values vastly different from what we observe: Much colder (near absolute zero): resulting in insufficient energy for particle formation. Much hotter: causing too-rapid expansion or preventing stable atom formation. The observed range (1 in 12.5 to 1 in 400) is narrow compared to the vast temperature ranges in the current universe. No apparent physical law requires this specific range. Yet, slight deviations could prevent the formation of elements, stars, and life. This fine-tuning is puzzling because random high-entropy (high-temperature) states are thermodynamically more probable, making our low-entropy, life-permitting universe seem remarkably improbable without an underlying cause.
The combined odds of the three parameters for the initial conditions being just right: Initial Temperature: 1 in 12.5. Initial Density: 1 in 10^60. Initial Quantum Fluctuations: 1 in 10^60 To get the overall odds, we multiply these probabilities:

Overall Odds = (1/12.5) × (1/10^60) × (1/10^60) = 1 / (12.5 × 10^60 × 10^60) ≈ 1 / (10^1.1 × 10^60 × 10^60) = 1 / 10^121.1. So, the combined odds of these three initial conditions being finely tuned just right for our universe are approximately: 1 in 10^121.1

Existence and properties of specific particles and forces: The existence of the strong nuclear force and its confinement property, which binds quarks together to form hadrons, is an empirical observation not derived from any known deeper theoretical principle. A universe without this force or with different confinement properties could not sustain the existence of stable atomic nuclei and the elements necessary for life chemistry. The existence of the electromagnetic force with its infinite range is not dictated by any known physical necessity. A universe without this force or with different properties could not support the formation of stable atoms, molecules, and the complex interactions that underpin chemistry and biology. The existence of the weak nuclear force and its involvement in nuclear processes like beta decay is an empirical observation not derived from deeper theoretical grounding. Deviations in the properties of this force could disrupt the delicate balance of nuclear processes that sustain stellar dynamics and the synthesis of heavier elements crucial for life. The existence of specific particles like protons, neutrons, and electrons is not dictated by any known fundamental physical principle. A universe without these particles or with different particle compositions could not support the formation of stable atoms, molecules, and the complex chemistry necessary for life.

Cosmological parameters: The expansion rate and dynamics of the universe, governed by the cosmological constant and the density of matter and energy, are not derived from any known deeper theoretical principle. Slight deviations in these parameters could have led to a universe that either collapsed too quickly or expanded too rapidly, preventing the formation of stars, galaxies, and the conditions necessary for life. The energy density and composition of the universe, including the relative contributions of matter, dark matter, and dark energy, are empirical observations not dictated by any known fundamental physical necessity. Variations in these parameters could have resulted in vastly different cosmic dynamics and structures, potentially rendering the universe inhospitable to life.

In each of these cases, the fine-tuning of these fundamental properties and parameters is an empirical fact, not a consequence of any known deeper physical necessity or theoretical grounding. The observed values and relationships appear to be meticulously calibrated, allowing for the emergence of the rich tapestry of structures, complexity, and ultimately, life itself. Even slight deviations from these exquisitely tuned values could potentially lead to a universe devoid of the intricate dynamics and conditions necessary for our existence. This remarkable fine-tuning of the fundamental laws, forces, and constants that govern our universe remains an enduring enigma in physics and cosmology. While our current understanding of the natural world cannot provide a deeper explanation for this apparent fine-tuning, it serves as a profound reminder of the delicate balance that underpins our existence and the vast realms of knowledge that still await exploration.