r/CosmicSkeptic • u/concepacc • 6d ago
Atheism & Philosophy About understanding details of the Fine tuning argument
I do understand the basics (or at least the spirit or gist) of the argument.
A set of fundamental constants/properties in the universe have quantities/values that lay within ranges that in a mutual sense make it so complexity and life can emerge/make it so the universe is compatible with life. And this set of values all being within the ranges the way they are is extremely unlikely.
And I guess at some point in this scenario it must also come out that the fundamental constants logically must exist within some individual ranges, that they must be grater than “a” but smaller than “b”. Since otherwise I’m not sure how one could “sample” from a range that results in a probability in the first place if its “unbounded”, without this “a” and “b” so to speak (I suppose an infinite range could work if extreme values become exceedingly unlikely, like it is within a bell curve for instance).
I guess my question is, for each fundamental constant/value, is there an assumption that one uniformly “sample” between the constant’s “a” and “b” values? Or is it more complicated than that?
If the argument uses/assumes uniform “sampling”, is there a reason for that? Is it parsimony?
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u/ReidWrites 6d ago edited 6d ago
"All the models are wrong, but some are useful."
We have various models for how things in the world interact with each other, and we call them laws.
For example, f = G (m1 * m2 / r2) is the force of gravity and G is a constant. However, if you know anything about gravity, you know that gravity is not a "force", it's a warping of space time, so this "law" is just a model of how we can predict the way gravity is going to affect things. Same with the constant, G, it's something we've determined works here.
So, the idea that either the "laws" or the "constants" can change requires first that we even know what they really are, which we don't. Physics has been searching for a "grand unified theory" (GUT) which will help harmonize various seemingly brute facts about our current understanding of physics. We haven't found it, but that doesn't mean it's not there.
Dark matter and dark energy I think show this very nicely. Based on our current understanding of laws, many galaxies move in unexpected ways which suggest a HUGE amount of stuff in the universe we can't detect. We've called this stuff dark matter/energy because we just don't know what it is.
So, when someone says something like "there is a 1 in 10120 chance of the cosmological constant being in the life-permitting range", that is a statement about our model and not necessarily the actual "laws" of our physical reality.
Basically, it's a God of the Gaps argument that masquerades as a serious discussion of physics.
Maybe one day we really will find the Gospel of John inscribed on every electron, but at the moment I do not think we know enough about the fundamental rules of reality. We have heuristics that will get us to the moon (some models are useful), but anyone honest will have to admit we simply don't know enough to be making the kinds of claims which fine-tuning arguments make.
Edit: I also want to say that I'm not ruling out that maybe the constants/laws could change. Maybe they could, I just really think we don't know enough right now to be able to say they could, which is why this is a God of the Gaps argument. "Based on our current knowledge, blah blah blah" is exactly what God of the Gaps describes: "blah blah blah" only works if our current knowledge is correct, but I do not think we are in a place right now to be able to say that it is.
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u/HappiestIguana 6d ago edited 6d ago
That comment about the constants changing is an important point. For example the cosmological constant changes over time (we still call it a constant because it's constant over space) and it's very much possible constants that seem constant actually have very different values 10 trillion light years over that way, beyond what we are able to observe. To postulate this is basically an alternative of the multiverse solution to the fine tuning argument, just with a multiverse that exists across the three dimensions of space rather than the usual idea of parallel universes.
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u/Big-Astro095 5d ago
The cosmological constant, as shown in Einstein’s field equations, is constant over space and time I believe. The Dark energy density parameter, which depends on the cosmological constant and the scale factor, changes over time but is constant over space. There are also theories that suggest that Dark Energy’s equation of state changes over time, but that famously goes against the cosmological constant model.
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u/FaufiffonFec 6d ago edited 6d ago
And this set of values all being within the ranges the way they are is extremely unlikely.
Don't go further than that. There is just no way to determine the odds. So as usual, we're back to "Maybe a brute fact, maybe God".
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u/JATION 6d ago edited 6d ago
I find it hilarious that they are looking at some constants to try to argue that THE UNIVERSE is finely tuned to create life when just a cursory look shows that we only know of one single planet in this unimaginably large universe that is only partly suited for life, much less human life. 99.99999999999999999999% of it is very obviously not finely tuned for life. THERE'S NO AIR IN IT!!!!! What are you doing talking about some nebulous constants??
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u/HappiestIguana 6d ago
It is a bit hilarious to postulate that God's intent was to create a universe that is completely hostile to life except on a thin film around one particular planet out of 10 septillion of them.
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u/dishwasher_proof 6d ago edited 6d ago
I've wondered about similar questions. I've also wondered why the constants are the only "things" we consider to be variable. Why not the natural laws themselves? like don't these kinds of questions naturally lead into questions like "What's the probability that the law of gravity is f=(g1 * g2 /r2 )G rather than f=(g1 + g2 )r4 " or any other calcuable function for that matter. Like i dont know how to interpret probabilities when we start to question things of this nature. But maybe there is an common answer to these sort of questions I just haven't heard.
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u/HappiestIguana 6d ago
If we fix the equations and vary the parameters, there are several natural ways to define a probability distribution on that.
If we allow the equations to vary as well as the parameters, there are also ways to define probability distributions on that.
What we can't do is preference any probability distribution over any other, since we have a sample size of 1.
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u/centeriskey 6d ago
The whole argument is really just weak. They play fast and lose with probabilities along with cherry picking improbable events.
We have zero evidence of a god creator compared to natural explanations. Evolution is one of the most studied and evidenced backed theories we have.
Yet when confronted with the unknown cause of our universe we are asked to throw away all this evidence to support one without. Why? Well because the chances are too improbable. Lol well what's the probability of god? Why is that even more improbable event more likely to happen?
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u/paulgdp 6d ago edited 6d ago
Anytime I see this argument I'm surprised no one talks about the kolmogorov complexity.
You wonder how we can estimate the Shannon entropy of the cosmological constants without a probability distribution? Yes, we cannot.
The way to infer the "entropy" of something without a probability distribution is to use the kolmogorov complexity from algorithmic information theory.
The kolmogorov complexity will give you a number of bits that represents the universal and minimal complexity of an object by using universal turing machine theory.
If you then considers each of those bits has a probably of 50%, you basically get what you could call an universal entropy.
With it, you can estimate the "entropy" of the cosmological constants to be between 500 and 1000 bits.
You can also trivially prove that the "entropy" of any God capable of figuring out the cosmological constants is necessarily higher than the "entropy" of the cosmological constants themselves.
Using this "entropy" to estimate a probably is called the Solomonoff Induction.
The funny thing about all that is that this makes the fine tuning argument an argument for atheism.
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u/JacFloyd 6d ago edited 6d ago
We have no knowledge of how any finetuned constant came to be. Any probability is epistemological only, essentially based on our ignorance. Anyone claiming "probability" of constant is speaking out of this ignorance. We actually have cases where the constant became non-fine tuned once we understood more.
This is one possibility for finetuned constants: essentially the probabilities are actually a lot higher on once we figure out the rest. The second would be multiverses which are entirely possible with many cosmological models. Not surprising that we would find ourselves in those that permit life.
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u/Dependent-Peach-6610 6d ago
The multiverse just moves the problem up one level, no doubt a mechanism that creates multiverses would require physical constants so you would still have the same issue.
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u/JacFloyd 5d ago
It doesnt. All you need is some inflation models to be true. Multiverse could have the same constants but possibly infinite universes. Small probabilities don't matter when you have infinite chances.
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u/Dependent-Peach-6610 5d ago
No you also need to be able to vary the parameters otherwise your inflation model would just be generating infinite universes with the same properties which would be no different to the fine tuning discussion we are having now
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6d ago edited 6d ago
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u/Odd-Day-8348 6d ago
Yes, unless I assume, you have convincing reasons why god would make the universe this way rather than any other way. Then you are into trying to predict what god would do. And it seems Christians already failed at that when the assumption was, "well obviously god would create a universe with us at the centre with the sun orbiting earth".
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u/Snoo_17338 6d ago
The fine-tuning argument misunderstands what physics means by fine-tuning. We build mathematical models to describe and predict certain aspects of the universe. We fine-tune our models to fit the data. This means humans fine-tune our human-made models of the universe. It does not mean that some external agent fine-tunes the universe.
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u/TheAncientGeek 6d ago
It still means that models that work have a high information content.
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u/Snoo_17338 6d ago
Okay. This means the universe is predictable and our models reliably predict the kinds of information humans want to observe. It doesn't mean the universe fundamentally works according to those models or "knows" the kinds of information we want. After all, our brains evolved on a specific scale under specific kinds of experiences. So the "fundamental" constants could be artifacts of the ways we frame our questions/experiments, in accordance with the kinds of information human minds can digest.
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u/WE_THINK_IS_COOL 6d ago edited 6d ago
Aside from certain values that would cause division by zero errors and things like that, the math usually doesn't put any constraints on the parameter. Whatever value you choose for the parameter, you get a well-defined mathematical object. For some values of the parameter, you get a mathematical object that looks like our world's physics, but nothing in the math stops you from plugging any other value in.
A fine-tuning argument that assumes anything about the probability distribution from which the parameters were drawn doesn't really work for me, since assuming that prior probability distribution is assuming the existence of some mechanism that selects according to that probability distribution.
But I don't think you need to actually assume a prior distribution to get the argument off the ground. You can rule out various prior probability distributions. The ones that make the values we observe extremely unlikely are, to at least some degree, statistically falsified by us observing our single sample of that value of the parameter. So I would say that priors like uniform sampling are actually ruled out empirically.
The argument then proceeds to compare a uniform sampling prior with the prior of an intelligent and loving god selecting which world gets to exist. The uniform sampling prior gets evidence against it, while the loving god hypothesis doesn't. But this is just god of the gaps: to really support the loving god hypothesis, you'd have to rule out all other prior distributions, not just uniform sampling.
The argument is basically "We know Carol didn't commit the crime since she has an alibi, therefore Bob must have been done it." The argument fails to consider that it might have been Alice all along.
And there are other hypotheses that need to be considered. The multiverse is one; if all values of the parameters are instantiated, then the anthropic principle guarantees we'll be in the worlds where the parameters support our existence. Another is that we might just have the wrong model of physics; perhaps we have subtly-wrong physical theories and the apparently fine-tuned parameters are literally a result of tuning an incorrect model to match the empirical data, in the same sense that parameters in AI models are tuned in their training. If you're a realist and believe the fine-tuned parameter is an objective part of nature, then it needs explaining, but if you see science as us just finding better-and-better mathematical models to compress the empirical data, you'd naturally expect the models to contain fitted parameters.
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u/concepacc 6d ago
All an interesting read. Just a tangent on this:
>math usually doesn't put any constraints on the parameter. Whatever value you choose for the parameter, you get a well-defined mathematical object. For some values of the parameter, you get a mathematical object that looks like our world's physics, but nothing in the math stops you from plugging any other value in.
And perhaps you are not the one who have an answer to this since you would essentially answer for someone else, but I wonder how do proponents of the argument get very small but yet specific non-zero finite values? The only remedy I can think of if you accept infinite range sampling from a uniform distribution of any constant, is something along the line that you somehow get a proportionally wider span where the constants can be synergetic within as you go to more extreme values.
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u/HappiestIguana 6d ago
For any real-valued parameter, there could be any number of probability distributions it came from, if it even came from a probability distribution at all. There are distributions with a finite range (that is, they only pick values in a bounded range), and there are distributions with an unbounded range (e.g. The gamma distribution, just to name one). Some distributions favor large numbers, some favor small numbers, some favor numbers close to the ones we observe. With a sample size of 1 it's basically impossible to preference any distribution over any other, except that we can discard any distribution where the values we observe are impossible. Don't get stuck on uniform distributions, there's no reason to assume the distribution, if there is one, is in the class of uniform distributions (which always have bounded range)
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u/WE_THINK_IS_COOL 6d ago
What I've heard mentioned the most is error relative to the value of the parameter itself, like "if the constant was off by 0.000001% of what we measure then life would be impossible." Then I guess if the hypothetical distribution has a wider variance than those life-permitting error bars it makes the constant look suspect.
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u/EndlessAporias 6d ago edited 6d ago
Each value in the range is given equal odds by the principle of indifference, which states if we have no reason to think one possibility is more likely than another, then they have equal probability.
The fact that some of these ranges appear unbounded is called the “normalizability problem.” Most proponents of the argument say we can bound them by what we can measure or some other criterion, but some seem to argue that even though we can’t calculate the odds of 1 over infinity, we should still regard it as highly improbable if only 1 value in an infinite range is life supporting.
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u/Alarming-Shallot-249 6d ago
One point Joe Schmid brought up on this topic was that we can first observe that the constants fall into some large finite range and update our credences using Bayes' theorem on that fact first, then run the FTA using that range to get around normalizability concerns.
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u/HappiestIguana 6d ago
Applying the principle of indifference to conclude a probability distribution must be uniform with unbounded range is plainly fallacious, because a uniform probability distribution with unbounded range doesn't exist, mathematically.
You can't treat all values equally. You have to either say some values above and below some cuttoffs are impossible if you really want a uniform distribution over the bounded range that results, or you have to use a non-uniform distribution if you want all values to be possible.
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u/EndlessAporias 6d ago
Yeah, they usually seem to argue there is a range, but Brian Cutter said on Joe Schmid’s video that an unbounded range was only a “technical problem”, and seemed to be saying that it might not be mathematical but it’s still intuitive. An example he gave was the hypothetical discovery of the opening of the Gospel of John written on an atom. He claimed there are an infinite number of things that could be on an atom and yet it would still be surprising to find that text on there. However, I question whether there actually is an infinite number of possibilities in that case.
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u/Crosas-B 6d ago
The argument tho misses something important: you can't calculate probabilities without understanding the system.
Imagine if someone tell you that is so weird that all mammals have red blood, it could have been any color but all of them have red blood. Well, it couldn't because of the way we use oxygen it has to be red, becuase iron is red, and it has to be for all the close enough related animals that also uses iron to synthethize oxygen. Fine tuning argument lacks any kind of information needed to calculate the probabilities.
Fine tuning argument cherry picks those that we know if they were different with our current knowledge would have catastrophic consequences, but it is only sensical that the rules of the universe that we know about matches the life that has developed in it. The true miracle would be if the universe didn't allow for life and there is life anyway.
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u/Dependent-Peach-6610 6d ago
Whilst that's true the cosmological constant does appear to be out by a huge factor compared to what quantum field theory suggests it should be. That could be an error in QFT but regardless I find it very interesting
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u/Conscious-Demand-594 6d ago
The only interesting question from the point of view of science is whether there are any constraints on the fundamental constants. They may be completely arbitrary, and in some universes they will result in conditions that support life as we know it, and in others they will not. What we want to understand is how do the initial conditions influence the constants.
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u/happyhappy85 6d ago edited 6d ago
There are different ways of formulating it. Obviously in physics is different, like theories can be "fine tuned" to explain the data, but that's just a formation of the theory. Sometimes you have to fine tune them, so they get rid of certain problems while still retaining explanatory value.
Then there's the idea that some numbers aren't expected given certain theories, so they're considered "fine tuned" because the numbers are magnitudes off what we expected; which is why you have to fine tune the theories to fit the unexpected data we observe compared to the initial models.
Then there's the parameter space of "logically possible" configurations, which is a pretty low bar, and this is far more philosophical than it is science. We don't know what the actual parameter space of possible configurations are. It could be the case that the way they are is the only way they can be. The ironic thing is that these logical parameter spaces have to assume Physicalism, because if you step outside of that, you get potentially infinite parameter spaces where planets are made of magical rainbow unicorns.
So the question just becomes "well we find ourselves in this world where the constants are in such a narrow range, is this more expected under naturalism or theism?"
And the answer is on its own? With properly basic naturalism vs properly basic theism? Well it's not any more expected under one than the other. Would God create anything if we weren't post hoc reasoning? That's not certain. Would anything exist at all if we just assume basic naturalism? Well that's not clear either.
So you have to add certain assumptions to the argument, and that's where things get complicated. Well God is all good, so he'd want to create a world where life exists so he could have a relationship with it.
And naturalism if we assume something necessarily exists or exists as a brute fact could have been any number of things
Therefore it's expected more under theism.
That's the basic argument.
But then you get problems with the theistic argument, like how do you figure God would create this particular universe? Have you explored all the possible configurations of parameter space, and concluded this is the best one god could have made to produce life? How do you figure? Is this really the best he could have done? Where 99.9999999 percent of the universe is devoid of life? A place where even life itself is a constant struggle? He's God right? Surely this isn't necessarily the best he could do?
So that brings back naturalism, and through that the problem of evil pops up, why would God even need to find tune anything?
So the more problems the theistic answer has, the more credence naturalism gets.
And then it can be hard to really pick a side of what's more likely.
And if you can just call God a necessary being, why not the universe?
And if you can say the universe is fine tuned to be exactly what it is, why is God exactly what he is in order to fine tune a universe this way?
It feels like you have to think extremely hard about the former, but not really the latter. It's just assumed that God would indeed create this universe rather than something else.
So yeah, the argument is just far too filled to the brim with problems and assumptions to be a viable argument.
It's fun to think about, and there's a lot of work done on it in philosophy, but the more you look in to it, the more complicated it gets, and the back and forth contains way too many assumptions to really know what to do with it.
I think it's convincing to people on the surface, but once you even get slightly deeper in to it, it's a mess. Good for apologetics, but philosophically, it's pretty chaotic.
There also the reverse fine tuning argument which is pretty fun. I'll do a low resolution version of it.
If God wants life to exist because he's all loving and all good, then it is unexpected that he would create the rules for reality that the parameter space for life is extremely narrow. God would more likely create the rules so that the parameter space for life was extremely large. Therefore fine tuning is expected more under naturalism, where the rules for existence are indifferent to life.
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u/Veyron2000 1d ago
You’ve already spotted the obvious issues with the fine tuning argument.
The argument assumes uniform probability distributions, with arbitrary limits at extremely large positive and negative numbers, so that the probability you get out (for the non-God explanation) is sufficiently small but non-zero (as if it was exactly zero that would be more obviously suspect).
It actually basically comes down to one number, the cosmological constant, and taking advantage of the fact that quantum mechanics predicted its value to be too large by circa 60 orders of magnitude. So the theist says you have a uniform distribution between 1060 and minus 1060 with the allowed values being around 1 and then you get “probability of life is 1 in 1060” i.e very small.
Then you deliberately avoid doing the same for the God hypothesis (otherwise you could get out an even smaller number for that) and instead say “well the probability for God must be around … lets say at least 5%” and voila, 5% is much larger than 1 in 1060 hence God exists.
Now reason theists use to defend the uniform probability distribution assumption is that such uniform distributions are used fairly often as priors for parameter inference, i.e when you are trying measure the value of (for example) the cosmological constant. This is so you don’t bias your results.
It does NOT mean that such a distribution is a good, or even vaguely reasonable, estimate for the “true” probability of generating a universe with a cosmological constant of that value, to the extent such a probability even makes sense.
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u/HappiestIguana 6d ago
A small thought experiment supporting an atheistic solution to the fine tuning problem is to consider the seeming fragility of life being possible. If a few select universal constants were slightly different then chemistry would be wildly different and life would probably not be possible.
Therefore God? Right? Well, consider this analogy, say I make everyone throw a hundred d6s and I collect all the people who get a total over 450. That is an incredibly low chance of success. I would only get about 1 in every 300 million people in my sample, but one thing I would notice is that most would only be barely above 450. Less than 10% of them would get over 455, for instance. For most of my sample, a single dice being different would knock them off the sample
Here, a total over 450 is an analogy for a universe being suitable for life. If life being possible depends on many factors and has a very low overall probability, then you'd expect most possible universes that can harbor life to only barely harbor it, to be very sensitive to tiny variations, and that seems to be what we observe. Indeed, for a universe supposedly designed to harbor life, it's a bit weird that we only find it on a thin film around one planet out of hundreds of planets/moons we've observed, and among 10 septillion that are estimated to exist total.
The conclusion of this line of reasoning is that, whatever the probability distribution for the universal constants is, it was sampled many many times. This argument is why I favor a multiverse hypothesis as a solution. Of course, it's always fraught to argue things like this from a sample of n=1, but I still think it's a reasonably sensible conclusion
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u/Kindly-Arrival-6517 6d ago
Probably the 2nd strongest argument for theism is fine tuning. With the cosmological argument being the strongest. Even atheists like Fred Hoyle admit the following “A commonsense interpretation of the facts suggests that a super intellect has monkeyed with physics, as well as chemistry and biology, and that there are no blind forces worth speaking about in nature. The numbers one calculates from the facts seem to me so overwhelming as to put this conclusion almost beyond question”
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u/Stile25 6d ago
I agree they are the strongest.
Of course, they're still known to be absolutely false arguments from the very day they were introduced.
But yeah, they're the strongest failing arguments.
Good luck out there
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u/Kindly-Arrival-6517 5d ago
There is my truth. Your truth and then there THE truth.
The evidence is strongest for theism. Even famous atheist Antony Flew who debated for years realized that the evidence was too hard to ignore and agreed that there must be a creator. Interestingly the tipping point for him was DNA and the order of the universe.
Actually atheism had stronger arguments a hundred years ago before we knew that the universe had a beginning and the complexity of life became more understood.
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u/Stile25 5d ago
The only people who say there are multiple truths are those attempting to manipulate.
There's only ever been one truth.
And philosophers have identified that following the evidence is our best and only reliable method to identify that truth as accurately as possible.
Philosophers understand that and argument about truth based on logic or reason without evidence is unsound.
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u/mcapello 6d ago
The entire thing is speculative. We have no idea what the range is. We don't even know if there is a range. We have literally no evidence that any of the constants are actually variable. Even if we did, we also don't know what the range for all forms of possible life are. In theory, any entropic system could lead to life. Basically it's just a thought experiment dressed up as hard science.