Summary of Victor Stenger’s Case against the Fine-tuning Argument
Victor Stenger is a physicist, philosopher and prolific author, and has recently published the book The Fallacy of Fine-tuning: Why the Universe is Not Designed for Us. It contains perhaps the best currently existing response to the creationist argument from fine-tuning from the perspective of physics. Now, other philosophical and mathematical responses exists, but this is a comprehensive overview of the scientific case against the fine-tuning argument. I will summarize some of the more interesting parts of Stenger’s case below by paraphrasing certain parts of the last part of the final chapter in the book (pp. 293-294) as well as mentioning other problems mentioned in other parts of the book.
1. Many proponents of the fine-tuning argument quote Stephen Hawking out of context to try and show that Hawking thinks that the expansion rate of the universe is fine-tuned. In reality, Hawking just lists this problem as a problem for the big bang theory before cosmological inflation is taken into account. When it is, the fine-tuning problem of the expansion rate goes away.
2. Many proponents of the fine-tuning argument appeal to the singularity theorem proved by Hawking and Penrose in order to try and established that the universe began in a singularity. However, a singularity would be very massive and have infinitesimal volume. This is forbidden in quantum mechanics due to Heisenberg’s uncertainty principle, which states (in one of its versions) that the uncertainty in momentum times the uncertainty in position cannot be less than a specific non-zero number. Thus, the theorem proved by Hawking and Penrose is not applicable anymore.
3. Claims about fine-tuning are made against the backdrop of our particular form of life, yet other forms of life may be possible.
4. Certain physical constants, such as the speed of light in vacuum (c), the constant in Newtons law of gravity (G) and Planck’s constant (h), are claimed to be fine-tuned, yet their values depends arbitrarily on the system of units used. In cosmology, for instance, c is usually set to 1 to make calculations easier.
5. Fine-tuning claims are made for ratio between electrons and protons, expansion rate of the universe an the mass density of the universe, but these values are set by cosmological physics and do not need to be fine-tuned.
6. The relative strength of electromagnetic and gravitational forces are not fine-tuned as this quantity cannot be defined universally, as it depends on what the mass and charge of the particles you are comparing have.
7. Proponents of the fine-tuning argument most often keep all other parameters as constants, and just varying one of them. However, change in one parameter can in many cases be compensated by a change in another parameter, making so that a larger set of possible parameters are consistent with life-permitting universes.
8. The Rare Earth hypothesis states that many parameters of the earth and our solar system needs to be fine-tuned for it to be hospitable to life. However, this does not take into account the billions and billions of planets that exist in the universe, which means that a planets that are life-permitting should occur several times.
Stenger lists many more arguments, and goes into the physics of it all at a pretty detailed level and concludes that the fine-tuning argument can be dismissed based on the science without postulating a multiverse.
17 thoughts on “Summary of Victor Stenger’s Case against the Fine-tuning Argument”
For a review by a cosmologist, enjoy: http://arxiv.org/abs/1112.4647
Instead of shamelessly promoting your own unpublished writings, maybe you should try to reply to the refutation I wrote over 4 months ago about some of your claims about the fine tuning argument and all of your creationist claims about evolutionary biology?
I think I will take this oppertunity to reinvigorate my interest in your creationist assertions, starting with your particularily flawed review of Coyne’s book.
Stenger has replied to that review, saying that it does not “invalidate these conclusions and misunderstands and misrepresents much of what is in the book.”
* My paper has just been accepted for publication in “Publications of the Astronomical Society of Australia”.
* I never made any claims about evolutionary biology, let alone creationist ones. “I am not in any way calling into question the truth of the hypothesis of common descent.” If you can provide a counterexample, go ahead. Where did I call into question common descent?
* The word “for” is not necessarily teleological. http://www.merriam-webster.com/dictionary/for, definition 7: “I’m a stickler for detail = I’m a stickler with respect to detail.” A more physics example is the sentence: “equation one is the equation *for* an open universe”. I very carefully defined what I meant when I claim that the universe is fine-tuned for life. It does not mean designed.
* We can do more than make claims about life as we know it. Martin Rees makes this point quite well so I’ll quote him: “Any universe hospitable to life … has to be ‘adjusted’ in a particular way. The prerequisites for any life of the kind we know about — long-lived stable stars, stable atoms such as carbon, oxygen and silicon, able to combine into complex molecules, etc — are sensitive to the physical laws and to the size, expansion rate and contents of the universe. Indeed, even for the most open-minded science ﬁction writer, ‘life’ or ‘intelligence’ requires the emergence of some generic complex structures: it can’t exist in a homogeneous universe, not in a universe containing only a few dozen particles. Many recipes would lead to stillborn universes with no atoms, no chemistry, and no planets; or to universes too short-lived or too empty to allow anything to evolve beyond sterile uniformity.”
* “we do not know that other configurations of physical constants are physically possible”. You still don’t understand the claim being made. The laws of nature define what is physically possible. Fine-tuning considers the consequences of changing the laws and constants of nature, and thus changing what is physically possible. It makes no sense whatsoever to ask whether changing physical constants is physically possible.
I’ll put roughly the same comment on the post you references above at my blog, so you can comment here or there.
If we look at their website, it does not appear as if this book review of yours has been accepted. Under the section “just accepted”, I can only see “Distance Measurements and Stellar Population Properties via Surface Brightness Fluctuations” by Alexander Fritz, “AMS applications in nuclear astrophysics – new results for 13C(n,Î³)14C and 14N(n,p)14C” by Anton Wallner and others and finally “The dark matter crisis: falsification of the current standard model of cosmology” by Pavel Kroupa.
The impact factor of the journal you mention is also about 1.5. Compare with the Journal of Scientific Exploration, who regularily publishes “articles” about Big Foot and the Loch Ness moster having an impact factor of 0.5.
As I showed in comments to the blog post, you advanced classic creationist arguments and tactics, such as saying that common descent does not make predictions. I disproved this claim. You also made several suspicious claims in your review of Coyne’s book, but I will detail them in a future blog post. Evolution is also more than common descent.
In the context of evolution, “for” signifies teleological preadaptation. It doesn’t matter what dictionary arguments you deploy.
Notice how the quote from Rees uses the phrase adjusted in qoutation marks. You might as well say that the universe is fine-tuned for Ipads, because the vast majority of hypothetically possible universes are incompatible with their existence.
You are presupposing an outdated ontology of physical laws. They do not decide how things act, they are only generalized and approximate descriptions of the behavior of matter. So when I talk about the configurations of physical constants that are physically possible, I am talking about the descriptions of a universe that are logically possible — i.e do not entail a contradiction. However, this is not the same as saying that these descriptions denotes a universe that is physically possible know a lot of things that are logically possible (say, a two ton rat), but are not physically possible. So showing that a universe is logically possible to exist is not the same as showing that it would be physically possible for such a universe to exist.
* Patience. I’m waiting on a figure reproduction permission from Cambridge University Press. The paper has passed peer and editorial review.
* You keep calling me a creationist. I never denied that common descent makes predictions. In fact, it was part of my argument that common descent does make predictions, but not all of those predictions can be tested by experiment. This is not a criticism of the hypothesis. My point is that scientific evidence is wider than experimental evidence. This point is obvious to an astronomer – I can’t do experiments on high redshift galaxies. One cannot refute fine-tuning by demanding experimental evidence. My point is that Myers is committed to the truth of hypotheses that are predictive and yet not experimentally testable.
* “In the context of evolution, “for” signifies teleological preadaptation”. I’m not an evolutionary biologist, so I cannot be using it in that sense. What jargon biologists attach to common prepositions is irrelevant for the rest of us. Fine-tuning is primarily concerned with physics and cosmology, where the preposition “for” is not a jargon term but retains its dictionary meaning. If you’d like me to rephrase my claim as “The universe is fine-tuned with respect to intelligent life” then that’s fine. No dictionary jiggery-pokery is needed.(Actually, “fine-tuned” is a metaphor (it’s like a radio dial) that’s also open to misinterpretation as teleology, so if there were a better term then I’d go with that as well. Fine-tuned is a technical physics term.)
* Rees says ‘adjusted’ to avoid its usual teleological implications. The ipad is not a candidate for the anthropic principle (we can observe the universe without ipads), so the cases are not comparable.
* I don’t understand your last paragraph. “So when I talk about the configurations of physical constants that are physically possible … [I am not saying] that these descriptions denotes a universe that is physically possible.” Could you explain further? If I understand your definition of a logically possible universe as “describable without contradiction”, then I agree that fine-tuning is about the set of logically possible universes. A two-ton rat is physically impossible given the laws of nature in this universe, but a two-ton rat would be physically possible if the laws of nature were different. The laws of nature describe(/prescribe/define/whatever-ontology-you-prefer) what is physically possible in any universe in which they apply. It then makes no sense to ask what physical laws are physically possible.
We can also observe the universe without humans. In fact, the vast majority of things you look at through an astronomical telescope is of a universe at a time when there was no humans.
I am making the distintion between logical possibility and physical possibility. If you prefer, we can call the latter “actual possibility”. I fully accept that a universe in which our form of life exists is an infitesemal slither of all logically possible universes. But is it an inftitesemal slither of all actually possible universes?
The confusion mostly arises when approaching the issue from a platonic realist perspective (where physical laws determine that which is physically possible), rather than treating physical constants as ingredients in physical models constructed by scientists. So what is the proportion of combinations of physical constants that describe a physically possible universe compared with all logically possible combinations of physical constants?
* “We can also observe the universe without humans”. If by “we” you mean us human beings, then your statement is necessarily false. In fact, the anthropic principle (in spite of its name) isn’t about human beings at all. It roughly states that if there are observers, then they observe a universe compatible with the existence of observers. That statement is true, and in fact a tautology, though not a trivial one. It doesn’t say that there are places or times in the universe that don’t contain observers.
* I think this is progress. When I say that “universe X is not logically possible”, I mean that the description of X contains a contradiction. When I say that “universe X is logically possible but not actually possible”, what is doing the disqualification? It’s not the laws of logic or mathematics, since X is logically possible. (I’m taking logically and mathematically possible to mean the same thing in this context.) It can’t be the laws of nature, since I am taking X to include a description of the laws of nature. There are no extra physical laws outside X with which one can disqualify X. So what makes a logically possible universe actually impossible?
* Contrary to Stenger’s accusation, I am not a believer in and do not defend platonic realism. Unfortunately, the language of realism is the most convenient for science – its just easier to talk about electrons as if they were real things. In Section 4.9 of my paper I argued that fine-tuning claims can be understood and affirmed by realist, instrumentalist, or whatever.
As an astronomer, you no doubt understand that when you peer into the telescope, you are peering back in time. What you are observing is the universe at the time when there were no humans.
For some reason, either unknown to us or differing depending on our interpretation, certain things that are logically possible just don’t become actualized. This is a fact, even if we may not be able to provide a rationale for why this is.
* By any definition of universe, we are not looking at a different, separate universe when we look through our telescopes. We are seeing a different place/time in this universe.
* Not good enough. To disqualify part of parameter space, we need some reason to think that such universes are not possible. The fact that they are not actual is no reason to think that they are not possible. This is the whole point of the multiverse – maybe they are actual, somewhere.
A time were no life existed — i.e. a universe free of observers.
It is not enough to say that it is logically possible that they are actual somewhere in another part of the multiverse. It has to be demonstrated as plausible. Otherwise there would be no distinction between logically possible and actualized universes. Everything that is possible would be actualized. So what is your evidence for the position that another part of the hypothesized multiverse contain a two ton rat? It may be logically possible for such a creature to exist, but that is not enough.
* “A time” does not “a universe” make.
“You cannot observe an empty house from the inside”.
“Yes I can. Look … there’s no one in the kitchen”.
“That only proves that from inside a house, you can observe that other parts of the house are empty. An empty room does not an empty house make.”
* I need to recap.
– I said: the relevant space of possibilities to which the life-permitting subset should be compared is the set of logically possible (i.e. consistently mathematically describable) universes.
– You said: the relevant space of possibilities may be smaller, because there may be logically possible universes that are not actually possible.
– I asked: what is it that makes a logically possible universe actually impossible?
– You said: I don’t know, but there must be something because otherwise we can’t account for the fact that certain possibilities aren’t actualised.
– I said: a) That reply only works if you know that these other possibilities aren’t actualised. Why not be a modal realist? I’m not a modal realist, incidentally, so don’t misunderstand the argument. David Lewis argued as follows: since we can’t see a reason for logically possible universes to be actualised, they must be all be actualised. Why believe in the notion of “actual possibility” instead of modal realism?
b) The fact that a state of affairs isn’t realised is no reason to think that it isn’t possible.
It’s quite a radical step to say that the reason some logically possibilities are not actualised is because there is this idea of “actual possibility” which I can’t define or give an example of but which looks at some logically possible universes and announces them to be disqualified from existence for no reason at all. As a physicist, I just don’t get it. I can write down the equations for a universe with less matter than ours, solve the equations, examine the solutions, predict what observations one would make. It’s exactly the same process as predicting what our universe would be like. Why should I believe that such a universe is not possible?
However, if you are observing the light from the kitchen (at a time when no one, not even yourself, is in the house yet), then that house is empty of humans (at the time thelight left the kitchen). The analogy falters because the distances (and therefore the time since the event you are observing occured) are very different.
Because there needs to be evidence to upgrade the status of an entity or event from “logically possible” to “empirically probable”. I have given examples of what I think are logically possible, but not very empirically probable. You seem to have attempted to counter them by saying something along the lines “well, maybe there exists a two ton rat somewhere in the multiverse”. That may, again, be a logical possibility, but it is a very weak argument for establishing it as an empirically probable conclusion.
Here is the Sombrero galaxy: http://hubblesite.org/newscenter/archive/releases/2003/28/image/a/format/large_web/
It’s about 30 million light years away, so we are observing light which left that galaxy 30 million years ago. Are we:
a) observing a galaxy in another universe?
b) observing another part of our universe?
c) something else.
I’ll give you a hint – no astronomer would answer a). “Our universe” refers to a spacetime region, not just a timeslice.
You still haven’t told me what “actually possible” or “empirically possible” means. Remember that this is a modal claim, not an epistemological one. The sentence “two ton rats possibly exist” is ambiguous. I’m not saying that two ton rats might actually exist, but we just don’t know. The claim is that there is a possible world (http://en.wikipedia.org/wiki/Possible_world) in which two ton rats exist. That world is probably not be this one. If the modal claim is true, it is true independently of whether they actually exist in this universe or out in the multiverse somewhere. I’m not claiming that “maybe there exists a two ton rat somewhere in the multiverse”. SImilarly, fine-tuning claims are modal, and thus the set to which the life-permitting subset should be compared is the set of logically possible universes.
I never claimed it was part of another universe, merely that you are looking at the universe that is devoid of observers.
I have explained what i meant by “logically possible”, “actually possible” and “empirically probable” a couple of times before. Logical possibility is those things that do not entail a contradiction. Actually possible are those things that do not entail a contradiction and actually have the potential to exist and empirically probable refers to those things that probably exists in the natural world.
I haven’t understood what you meant by “actually possible”, “plausible”, “physically possible”, “empirically probable”. You haven’t defined the terms, nor otherwise tell what these terms refer to. They’re used almost interchangeably in the posts. The only difference seems to be where “probable” takes the place of “possible” (something “empirically probable” seems to be an event or entity “more probable” than something “only actually possible”.)
I would be interested to read if you define these terms somewhere, and/or explain them. Intuitively, I get they’re meant to be a middle ground between logically possible and actualized, and nothing else.
I have defined most of those terms in the comment section. Read before posting.
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