Having watched other videos by this guy, that’s a good call. He’s the sort of guy that fundamentalist Christians think is really smart, because he uses lots of big words from science and philosophy. But if you actually understand the context of those terms, he doesn’t really know what he’s talking about. (I’m referring to the young hipster host of the video channel. Barnes, I know nothing about.)
To be clear, I understand that fine-tuning is a legitimate issue in cosmology. I’m just criticizing those who try to turn this into an argument for a god.
The following looks like a good example of how it can be treated as a scientific question, but I admit it’s way above my pay scale:
Reading fine-tuning as though it is some sort of theistic term, is to attribute a connotation to the meaning of the term that is not intended.
Evidence that something is fine-tuned might have bearing on debates around (a)theism, but that is not to say that the concept of fine-tuning is inherently theistic.
As much as he is a great, handsome and articulate guy, what primarily draws people to his channel is who he hosts and the topics that he features.
That’s interesting. Why would you criticise the people instead of their arguments?
What are these “different things entirely”? Are they material or immaterial?
Of course. That was why I was alluding to angels in my post, which @John_Harshman then spelled out explicitly. If you believe in them, angels are an example of life without the conventional bounds of energy or mass. And most Christians do believe that God created an entire world filled with numerous angels before he created anything material. But then the FTA isn’t talking about this. The FTA doesn’t discount the possibility that there could be other regions of stability (i.e. producing interesting universes) in the parameter space of fundamental constants, as @david.heddlesaid:
Let me say this again: the fine tuning argument does not rule out the possibility of other sets of constants, very different from our own, producing habitable universes. It merely states that small excursions from where we are would result in a loss of habitability.
In the case of angels, it might not even be possible to characterize them by a mathematical equation resembling anything of the physics in our universe, so the FTA doesn’t apply to those.
I don’t know much about the host of Capturing Christianity, but Luke Barnes is an expert on the FTA. He’s a research astrophysicist who has published several papers on this, including a book on the FTA published by Cambridge University Press, in addition to the papers that @ThomasTrebilco already mentioned. Barnes is also referenced extensively in the SEP article on the FTA.
Admittedly, FTA is more discussed by philosophers than scientists, but I don’t view this as a weakness; I personally don’t think FTA is a scientific argument for God; there’s a lot of philosophical debate to be had on what are the implications of the apparently “fine-tunedness” of the fundamental constants before we get to any sort of theism.
But what are angels? Most just conceive of them as people but with special powers, like characters in a Marvel movie or something. I don’t really see how that is germane to the present discussion. I am suggesting there are infinite numbers of potential universes that we cannot even imagine or describe because their fundamentals are so different from the only universe we know. So how can we predict what will or will not arise in them?
I don’t think anyone has answered the question in my OP: Would the scientist witnessing the Big Bang be able to predict the existence of giraffes? If so, how?
The fine tuning argument seems to be based on the premise that the laws of physics could have been different. Yet we have no evidence that the laws of physics can be different from what they are, hence the fine tuning argument actually rests on an entirely speculative premise in the first place.
Merely pointing out that you can imagine a God that can make physical laws and set them at different values doesn’t undermine that we observe them as apparently unalterable.
On a related note with regards to the implications for theism/atheism of the supposed fine-tuning, whatever collection of values you get you’re going to need some explanation to account for.
A point often brought up by theists is that to have some deeper explanation for fine-tuning, you’re just going to be pushing the problem of the probability of the parameters back to that deeper explanation instead. So the idea is that the explanation for fine-tuning must itself be fine-tuned such that it results in the particular values and constants we observe. Hence it too must be very unlikely.
But that very same problem applies to theism as an account for fine-tuning. You are now picking out a particular God from the space of all possible Gods, with the exact and unlikely attribute of wanting to design this particular universe with this particular set of initial conditions and physical laws. Hence you have made the a priori probability of your God at least as unlikely as the problem you are trying to solve: the unlikelihood of the values of the physical constants, and the initial conditions of the universe.
So the bayesian prior of the explanation you are proposing is exactly as abysmal as the chance origin of those (assumed to be alterable) laws and constants in the first place.
We could call it the fine-tuning argument against the existence of God.
As @dga471 said, this is not what is meant by “fine-tuning” in physics. Fine-tuning just refers to the range of possible changes one can make to fundamental constants. You are talking about changing something that is more fundamental than the fundamental constants. This is sometimes talked about in the cosmological literature, but not as widely as just changing the fundamental constants.
We know that even if stars are not available, there are alternative structures that could form the conditions for life, e.g. dark matter annihilation or the CMB supplying the energy sources. We even know the ranges of fundamental constants required to form some of these alternatives.
Astrophysicists have looked carefully. Indeed, I would argue that our Universe is not fine-tuned for life (at least astronomically, I don’t know about biologically) in the sense that by changing fundamental constants, we can produce a Universe where there are more areas where life-as-we-know-it can exist than our Universe due to new structures that can be produced in other Universes.
For example, by changing fundamental constants, Galactic Habitable Zones, an area of galaxy where everywhere is habitable can exist (none exist in our Universe). Further, by changing fundamental constants, we can greatly prolong the amount of time in which the CMB itself produces enough heat to cause the entire Universe to be a giant habitable zone.
I would go as far to say that our Universe is hostile to life.
Indeed, in cosmology, the “fine-tuning” problem is not a “fine-tuning problem for life”, but rather “fine-tuning problem for the Universe as we see it”.
No, this depends on the particular interpretation of QM.
How small though? I think that a lot of people will be surprised that the supposedly small excursions are not that small at all (if one can even define ‘small’ or ‘large’ for these numbers). For example, the fine structure constant can be changed by an order of 10^4 while still keeping life. The stringest constraint is on the down quark mass, which cannot be changed beyond about ~1 order of magnitude.
No, but not because of fine-tuning or lack thereof.
No, it is based on the premise that the fundamental constants, not the laws of physics, could have been different. There is an extension of the fine-tuning problem that involves different universes possessing different laws of physics, but that is not what is typically discussed in the scientific literature.
The possibility that the chemistry of life could have started in our universe only 10–17 Myr after the Big Bang argues against the anthropic explanation for the value of the cosmological constant (Weinberg, 1987), especially if the characteristic amplitude of initial density perturbations or the level of non-Gaussianity is allowed to vary in different regions of the multiverse
As this is 200-300 Myr before what is usually accepted as the formation of the earliest stars, this would take some major tweeking of density perturbation to overcome the Jeans instability internal gas pressure at such elevated temperature, would it not?
(Be assured I am an inquiring mind only; I make no representation as to possessing the required skills to actually contribute more than lay questions in this area.)
There’s a link to his CV there, which has details about that.
Quote from the paper:
However, a number of philosophers have cast doubt on whether this intuition [that fine-tuning demonstrates the improbability of a life permitting universe] can be made rigorous. McGrew, McGrew & Vestrup (2001, hereafter MMV) and Colyvan, Garfield & Priest (2005, hereafter CGP) have argued that the relevant probability measure, because it is spread evenly over an infinitely large range, cannot be normalized and hence the relevant probabilities cannot be calculated. These papers are mostly concerned with the fine-tuning argument for the existence of God, but apply equally to the inference from fine-tuning to the existence of a multiverse. In a similar vein, Halvorson (2014) has argued that a correct understanding of the probabilities shows that a life-permitting universe is unlikely on any assumptions about its origin, and thus fine-tuning cannot be used to argue for anything deeper than the laws of nature. Our goal here is to use Bayesian probability theory, as it is employed in theory testing (or model selection) in the physical sciences, to show that we can make rigorous the claim that the fine-tuning of the universe for intelligent life renders our universe exceedingly improbable. There really is something to be explained. Precisely what (or Who) that explanation is, is left as an exercise for the reader.
Yeah, I think so. The paper I linked touches on this:
Philosophical discussions of the fine-tuning of the universe for life have often failed to recognize the context in which physicists have made their claims. ‘Fine-tuning’, a metaphor that brings to mind a precisely-set analogue radio dial, is used as a technical term in physics.
It would seem like you agree with these authors:
where they say:
Instead, we suggest that fine-tuning requires no special explanation at all, since it is not the Universe that is fine-tuned for life, but life that has been fine-tuned to the Universe.
Did you look? I’m doubting that you did. I find a single publication that might fit your claim: “The Fine Tuning of the Universe for Intelligent Life.” Barnes, Luke A.; Publications of the Astronomical Society of Australia, 29, 4, 529-564 (2012). It’s a review, not actual theoretical work, but it’s something. Still, it isn’t much.