Salvaging the Past Eternal

In WLC 2 – Cosmological Argument (“God Did It”), I wrote about Craig’s Argument from First Cause, focussing more on where he goes with assumption that the universe has a beginning rather than on that assumption itself.  In A Little Expansion on the Lightness of Fine-Tuning, I presented a perspective in which the expansion of the universe is time (that is not a typo, I mean “is time” not “with time”).

Now I understand that not everyone will be on-board with the idea that what we perceive as time is the expansion of the universe, so just take what follows as an explanation as to why I personally reject Craig’s claim that the universe began with the Big Bang (or if he’s sufficiently honest with himself, shortly before the Big Bang).

If universal expansion is time, then it would seem to make sense that if you ran everything backwards, you’d see the universe shrinking from its current size back to about something the size of a grapefruit.  There wouldn’t be a constant speed of shrinkage though, because the rate of expansion of the universe is inversely proportional to the age of the universe.  You’d see the shrinkage increasing in speed as you wound the clock back, right up until you got to the grapefruit and then … nothing.

Now, when I say “nothing”, I don’t mean that the grapefruit would have sprung into existence and if you continued winding the clock back there’d be nothing.  Remember that expansion of the universe is time, so if there is no universe there would be no time to wind back on the metaphorical clock.  Instead what I mean is that the universe would still be there, grapefruit sized and you could "wind the clock back" as far as you liked and the grapefruit would be there.

The expansion that we see in the universe is due to the fact that expansion is retarded around concentrations of mass-energy (we call this phenomenon “gravity”).  If the universe was not lumpy, but smooth instead, the expansion would be impossible to see – not only because we would not be here to see it, but because our rulers would be expanding at the same rate as the rest of the universe and the universe would always be a given number of cubic ruler lengths in size.  Time would still exist, since we’d still be expanding, but time as well would be impossible to detect – if the universe is smooth, there’d be no appreciable difference between moments.  Time would only become meaningful once change manifested, such as during an event such as the one that led to the Big Bang (let’s call it the Before Big Bang Event – 3BE).

So, sure, it makes sense to consider time as originating at 3BE and ignore all time before that, but it does not mean that time (or rather expansion) really commenced at that event.

I posed a puzzle in Hugging the World which may not have appeared to have been particularly relevant at the time.  In the answer (in the comments) Hausdorff and I note that if you increase the radius of a circle by 1 unit, you increase the circumference by 2π units.  This works if the units are attometres (very small) or exametres (very big).  In fact, you could take a circle of radius 1 attometre and increase the radius by 1 metre changing the circumference from about 6.283x10^-18m to about 6.283m.  To all intents and purposes, the expanded circle has a radius of 1m and it is as if there hadn’t been an original circle at all.

The expansion of the universe is analogous, it might not be strictly true to say that there was no time before 3BE, but to all intents and purposes it makes no difference if we assume there wasn’t.  Well, that is apart from a minor problem we get with this sort of flexibility, which is the fact that people like Craig come along and try to poke their gods into the very tiny gap.

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If you don’t like my argument, you are welcome to try Victor Stenger’s (he has the benefit of being a published physicist).  Alternatively you can look at the document on which Craig hangs his argument (at least in his debates).  Note that the authors don’t draw the same conclusion that Craig does, they write:

What can lie beyond this boundary? Several possibilities have been discussed, one being that the boundary of the inflating region corresponds to the beginning of the Universe in a quantum nucleation event. The boundary is then a closed spacelike hypersurface which can be determined from the appropriate instanton.

They merely mention the quantum nucleation event as one of the options.  There are several other possibilities some of which are described by Stenger.  In some of these there is a discontinuity at the 3BE, which in my model isn’t as extreme as for some of Stenger’s options.  In my model, it’s just the transition from a(n effectively) smooth universe to a lumpy universe – which might cause a bit of a bang, but does not require any change to the underlying processes.

Penrose's Conformal Cyclic Cosmology model is also worth a look.

Another Chance of Design - Response to Travis R

There's been a short exchange in the comments following Chance or Design:

measureoffaith - FYI, the objections you list here appear to have been sourced from WLC rather than Robin Collins, and the accompanying reference to Penrose is on pages 762-765 of TRtR (The Road to Reality).

neopolitan - Thanks, I've updated accordingly. I don't think that pages 762-765 say what you want them to say. Penrose is arguing against the anthropic principle. Towards the end of an earlier section, "28.6 The anthropic principle", he writes (having linked the strong anthropic principle with a creationist god hypothesis):

"My own position is to be extremely cautious about the use of the anthropic principle, most particularly the strong one. My impression is that the strong anthropic principle is often used as a kind of ‘cop-out’, when genuine theoretical considerations have seemed to reach their limit. I have not infrequently heard theorists resort to saying something like: ‘the values of the unknown constant parameters in my theory will be ultimately determined by the anthropic principle’. Of course it might indeed ultimately turn out that there is simply no mathematical way of fixing certain parameters in the ‘true theory’, and that the choice of these parameters is indeed such that the universe in which we find ourselves must be so as to allow sentient life. But I have to confess that I do not much like that idea!"

Note that he moves from having particular issue with the strong anthropic principle to just referring to it as the anthropic principle. Thus, when he's protesting strongly against the anthropic principle in a later section, he is most particularly protesting against the strong anthropic principle, and thus against your god. Given the context, it's a little disengenuous to call upon Penrose in support of your case.

I see no strong objection in Penrose's book against multiverses. Even when we limit ourselves to the very specific thing that WLC could be thought of as honestly referring to - the extravagance associated with having such a large, long-lived universe when perhaps we need a much small(er) region of order, no more than one galaxy, with the current laws in place only for as long as required for humans to evolve - we see that Penrose is arguing that for the purpose indicated (creating us, apparently) there would have been 10^10^123 more options that were significantly less extravagant. This is a strong argument against god, not a strong argument against multiverses. If anything, it implies that if there are multiverses (and thus more likelihood of the initial conditions from which intelligent life might spring) then the argument against god only increases.

measureoffaith (writing as Travis R): You assume too much. I don't "want" Penrose's argument to say anything in particular, nor am I making a case for any particular view. I was simply skeptical of the story put forth in your original version and so wanted to inform you of the correct sources after locating them for myself. Perhaps I should have been more explicit - it is WLC, not me, who refers to pages 762-765 of Penrose'sTRtR in the context of the quote. So the point was that your remarks about WLC presumably (and amusingly) referring to pg 784 is a strawman and is probably best exorcised from the post. As far as I can tell, WLC accurately characterizes the cited argument from Penrose, though he simultaneously fails to acknowledge the accompanying implications for theism that you outlined.

You are right, Travis, I assumed too much and misspoke (or miswrote).  I perhaps should have written " I don't think that pages 762-765 say what WLC wants them to say" or " I don't think that pages 762-765 say what John Piippo wants them to say" or " I don't think that pages 762-765 say what the theist might want them to say".  Probably, however, I should have just stuck with the facts and avoided speculation as to what other people want.

My point was that John Piippo was presenting arguments against the multiverse and had quoted WLC who made reference to Penrose.  And in the Penrose book, the word multiverse is only used once, on page 784, after which he uses the term "omnium".

It is true that WLC, as you linked, was referring to a different section of Penrose's book.  The questions then are whether WLC was "accurately characterising" Penrose's argument - and whether John Piippo was accurately reporting WLC's case.  WLC seems to have used Penrose repeatedly, in his book On Guard, on the page you linked and also at his Defenders podcast.  Here's what WLC had to say in the last of these:

Moreover, thirdly, the Many Worlds Hypothesis faces what may be a truly devastating objection. Do you remember when we talked about the thermodynamic properties of the universe, we discussed Boltzmann’s Many Worlds Hypothesis? You will remember that the Austrian physicist Ludwig Boltzmann tried to explain away the current disequilibrium of the universe by a kind of Many Worlds Hypothesis. He said that the universe as a whole really is in a state of equilibrium but there are just little pockets of disequilibrium throughout the universe, and these are different worlds. He called them “worlds” and we are one of these little pockets. We are one of these worlds. You will recall what sank Boltzmann’s hypothesis was that if our world is just a random member of a World Ensemble like this, then it’s vastly more probable that we should be observing a much smaller region of order than the vast universe that we do. In order for us to exist, all you would need would be a small fluctuation from equilibrium, say, enough to produce our solar system and not an entire universe which exists in such a state. It turns out that a parallel problem faces the Many Worlds Hypothesis as an explanation of cosmic fine-tuning.

The Oxford University physicist Roger Penrose has pressed this objection with great force. Penrose points out that the odds of our universe’s initial low entropy condition existing by chance alone are somewhere on the order of one chance out of 10^10(123). A truly incomprehensible number. By contrast the odds of our solar system’s forming by just a random collision of particles, Penrose calculates to be about one chance out of 10¹⁰⁽⁶⁰⁾. A number which is so tiny in comparison to 10^10(123) that Penrose calls this number “utter chicken feed” in comparison with 10^10(123). What that implies is that it is far more likely, incomprehensibly more likely, that we should be observing an orderly universe no larger than our solar system, since a world like that would be unfathomably more probable than a finely tuned universe like ours.

To me, this is not an "accurate characterisation" of what Penrose had to say.  Craig was very clearly implying that Penrose was pressing an objection to the "Many Worlds Hypothesis as an explanation of cosmic fine-tuning".  It's very difficult to interpret what was written here differently. 

Now, Penrose did write:

Much more problematic are versions of the strong anthropic principle, according to which we try to extend the anthropic argument to determine actual constants of nature (such as the ratio of the mass of the electron to that of the proton, or the value of the fine structure constant §26.9, §31.1). Some people might regard the strong anthropic principle as leading us to a belief in a ‘Divine Purpose’, whereby the Creator of the universe made sure that the fundamental physical constants were pre-ordained so as to have specific values that enable sentient life to be possible. On the other hand we may think of the strong principle as being an extension of the weak one where we broaden our questions of ‘where’ and ‘when’, so that they apply not just to a single spacetime, but to the whole ensemble of possible spacetimes (Fig. 28.13b).27 Different members of the ensemble might be expected to possess different values for the basic physical constants. The where/when question now also involves a choice of universe within the ensemble, so again we must find ourselves in a universe which permits sentience to come about.

Penrose is not necessarily talking about a multiverse here, but of an ensemble of "alternative universes", which involves a range of possible universes - not necessarily a range of instantiated universes.  The difference here is subtle.

Put roughly, we arrive at the idea of a multiverse via three possible paths, none of which involve thinking about a god: there is something like string theory in which each universe is a different solution to the equations, none of which has a higher likelihood than any other; there is the patchwork greater universe, in which for one reason or another, the laws of physics and the fundamental constants vary from region to region (eternal inflationary theory fits in here); and, some sort of cyclical or branching multiverse, like Penrose's CCC or a mother-daughter relationship between universes mediated by black holes, in which the constants are randomised in each cycle or branch.

The ensemble of worlds idea is a little different, especially as it pertains to the strong anthropic principle.  The basic idea is that not only is it a truism that we live in a universe in which life of our sort is possible, but also that sort of universe must also be possible - our sort of universe is a necessary member of any set of possible universes, by virtue of the fact that at least one example of our sort of universe exists.  If you come up with a theory that expressly prohibits a universe of the sort we live in, then your theory is wrong.

Just in case it is not entirely clear, the difference between the multiverse and the world ensemble is the direction from which the idea is approached.  As I wrote in Chance or Design, consideration of fine-tuning resolves down to chance or design.  If you find design to be unpalatable, then you are left with the question of how it could be that a universe so (apparently) unlikely as ours should exist.  A potential solution hangs on the notion that our universe, however unlikely, is still possible (and necessarily so, since it is existent).  This is the point at which you might posit a world ensemble, an array of possible universes, all slightly different and numerous enough to drive the posterior likelihood of our sort of universe towards unity … Pr(our sort of universe|world ensemble) -> 1.

What you can't do, legitimately, is suggest that there is a world ensemble purely on the basis of finding design unpalatable.  What you can do, legitimately, is look around and see whether there is any good reason for thinking a world ensemble exists.  It is at this point that you might meet up with multiverse theories coming in from another direction.  Some theists might not believe that multiverse theories arose independently of apologetics, but there are some who are becoming aware that this is in fact the case.

Another approach is Bayesian in nature (the equation above should have given this away).  We are considering a posterior, P(U|WE) which is given by the prior P(U) multiplied by the likelihood P(WE|U) divided by the marginal likelihood P(WE).  If we were to erase all knowledge of there being any universe in existence, what is the (marginal) likelihood of a world ensemble?  I'd suggest that this would approach zero, since the absence of any universe doesn't move us anywhere close to thinking there should be many of them (that are possible).  Therefore, we have a very low number, according to fine-tuners, for P(U) divided by a very low number.  This is rather arbitrary, but we could say that it's close to zero - especially if we were to stipulate that this world ensemble should be very highly populated given that the more highly populated it is, the lower P(WE) would be.

So, P(U)/P(WE) ≈ 1 and therefore P(U|WE) ≈ P(WE|U).  We need to consider how likely a world ensemble is, given the existence of our universe.  We could consider this in terms of how likely it would be that there is no world ensemble, given the existence of our universe - in other words, how likely would it be that, if there were only one universe, this would be the universe that came into existence?  If you say "very unlikely", then you are saying that a world ensemble, given the existence of our universe, is "very likely".  Once we've accepted that a world ensemble is highly likely, we need only to work out how populous this world ensemble would be.  With nothing else to guide us, we find ourselves being driven towards an infinite number of universes - because there is one population size for the world ensemble to the left of three and an infinite number of sizes to the right, so it's more likely to be a population size to the right of three.  Keep going (forever) and you'd eventually arrive at the conclusion that infinity is the most likely size.

I'm aware that this argument is a little dodgy, but fortunately, we don't need to rely on Bayesian skulduggery nowadays because we have pretty clear indications that the multiverse is an actual thing.

Anyway, it is very clear that, in pages 762-765, Penrose was forcefully dealing with a theistic version of the strong anthropic principle because he kept mentioning a Creator.  WLC cannot be thought of as "accurately characterising" Penrose's position when he fails to mention that.

Chance or Design?

In Barnes' Objections to Fine-Tuning, I concluded that there are only two fundamental responses to claims fine-tuning, that fine-tuning (and/or the appearance of fine-tuning) is due to chance or that fine-tuning (and/or the appearance of fine-tuning) is due to design, since the other options inevitably collapse down to chance or design.

We should perhaps revisit Barnes' "11 objections" in light of this:

Chance: It’s just a coincidence

Chance (overlaid by an appeal to ignorance): We’ve only observed one universe, and it’s got life. So as far as we know, the probability that a universe will support life is one out of one!

Chance/Design: However the universe was configured, evolution would have eventually found a way

Chance/Design (with another appeal to ignorance): There could be other forms of life

Chance/Design: It’s impossible for life to observe a universe not fine-tuned for life

Chance/Design: Maybe there are deeper laws; the universe must be this way, even though it looks like it could be other ways

Chance: Maybe there are bajillions of universes, and we happen to be in one of the few that supports life

Design: Maybe a physics student in another universe created our universe in an attempt to design a universe that would evolve intelligent life

Chance: This universe with intelligent life is just as unlikely as any other universe, so what’s the big deal?

Chance: The universe doesn’t look like it was designed for life, but rather for empty space or maybe black holes

Design: Fine-tuning shows there must be an intelligent designer beyond physical reality that tuned the universe so it would produce intelligent life

I have left a few of them as undetermined, Chance/Design because, at the end of the day, these "objections" don't really distinguish between the two fundamental options.  For example, while "(no matter how) the universe was configured, evolution would have eventually found a way" implies an end goal (intelligent life) that evolution is "trying" to achieve, there's nothing inherent to the argument that prefers (cosmic) evolution being designed to find intelligent life over (cosmic) evolution simply stumbling upon it.  The latter sort of relies on our knowledge that intelligent life is - at the very least - possible in one possible sort of universe, even if it may be improbable and the implication is that, given enough time and/or space, (cosmic) evolution would therefore eventually lead to intelligent life.

The main problem, the problem that theists want us all to come unstuck over, is that the fine-tuning of our universe for intelligent life does appear to be highly improbable.  We are supposed to throw up our hands and say "It's so unlikely that this should have happened by chance, so it must have happened by design.  Therefore, god."

It's for this reason that the multiverse is disliked by some theists, the multiverse short-circuits the theistic fine-tuning argument, because if there are an infinite (or sufficiently large) number of universes, with random tunings, then it becomes a lot more likely that some of them will be tuned sufficiently well for intelligent life.  If there are universes without end, a potential infinity of them, and it is possible that a universe may be tuned for intelligent life (which we know to be so), then it becomes statistically certain that there will be universes in which intelligent life arises - so such a universe existing becomes unsurprising and its existence cannot be counted as evidence for design.

Note that a universe with intelligent life is not evidence against design in and of itself but, given a claim with respect to a particular type of designer, a particular type of universe can be evidence against that designer (hence the problem of evil and the existence of vagueists, theists who strip away anything and everything associated with their god that might permit it to be falsified).

Barnes' list does have a multiverse related "objection" to fine-tuning: "Maybe there are bajillions of universes, and we happen to be in one of the few that supports life".  This is a somewhat flippant way to describe the multiverse, but they seem to be Luke Muehlhauser's words, not Luke Barnes'.  In the Pale Blue Dot podcast that Barnes appeared on, he confirms that we don't necessarily need an infinite number of universes, merely "enough" to make the supporting of life, somewhere - in one of those universes, likely.

This is part wriggle and part lure.  It seems reasonable to answer the argument that this universe is highly unlikely with one that, while not certain, nevertheless is likely.  However, the theists have a philosophical argument to the effect that their god is not only likely, but necessary.  In their minds, it doesn't matter if our universe is likely on a naturalistic assumption, given the multiverse - because they have the universe being the necessary product of a necessary being.  (It doesn't seem to matter to them that their necessity arguments have holes in them large enough to fit a few multiverses - they still have an argument.)  The lure involves encouraging those thinking about multiverses to satisfy themselves with a less than infinite number of universes (even a less than ridiculously huge, but not infinite, number of universes).  It's more of a rhetorical trick than anything else since the equations will tell us how many universes fall out of a multiverse theory, not any desire to explain fine-tuning.

Rather strangely, when discussing the multiverse with Muehlhauser, Barnes doesn't start with any of the scientific theoretical models that lead to a multiverse, like Guth's eternally inflationary multiverse, or string theory.  No, he starts with a couple of philosophical multiverse - although he does express bafflement at them.  Perhaps, we could think he's just dispensing with the nonsense first.  But no.

Directly after mentioning (and mischaracterising) eternal inflation, he leaps into typicality and Boltzmann brains.  Now I know that some well-educated, apparently sane and respected people do apparently take Boltzmann brains seriously, but I don't.  Briefly, the idea is that random fluctuations in thermal equilibriums, given enough time and space, will sometimes create a "brain", which I interpret to be little more than a nexus of something or other that is (or becomes) conscious, but is not necessarily encased in walnut like globs of flesh.  These could fluctuate into existence with a complete history in place and, albeit briefly, it would be impossible to distinguish between the existential experience of these Boltzmann brains, and that of our brains.

Furthermore, the argument goes, these fluctuations would be far more common (due to entropy considerations) than instances in which brains like ours evolve out of some primordial soup over a period of three to four billion years.  So, if this were true, the fact (if it indeed is a fact) that we humans have the nature that we have rather than being Boltzmann brains would be very unlikely.  We'd be very untypical of intelligent beings in general, since most of them would be fluctuations that dissipate soon after coming into existence.

I think this is a nonsense argument for the basically the same reason that, although it is theoretically possible in quantum physics for someone to spontaneously teleport from one spot to another, spontaneous quantum teleportation of humans will never happen.  The fluctuation required for an intelligence (even one as humble as my own) to come into existence and have pre-loaded experience is extremely specific - it's very highly ordered, which means that it's very low entropy (it's also very "surprising" but more of that in a later post).  I would consider the fluctuation of this intelligence into existence, pre-packaged with experience and awareness, without the slow grind of evolution behind it to be sufficiently astonishing as to be miraculous.

What I observe, as inherent to the Boltzmann brain argument, is an effect that I'd like to term "inconsistent poverty of imagination".  The theist is willing, when confronted with the idea of a multiverse, to imagine all sorts of nonsense and then place what we know to exist (intelligence based on evolution from very humble beginnings) on a par with the nonsense that they just thought up (intelligence based on thermodynamic fluctuations in some high entropy region of a universe or multiverse), but when asked to imagine alternatives to their god, all that imagination suddenly dries up and they can't think of a thing.

There are also rhetorical games played with infinities.  If there are an infinite number of universes, then anything that can happen will happen, and if something can (and does) happen, it will happen an infinite number of times.  This means that if Boltzmann brains are possible and they can fluctuate into existence, then they will do so an infinite number of times (but not necessarily everywhere, all the time).  Similarly, if intelligence as a consequence of cosmic and biological evolution is possible, then it will happen and it will happen an infinite number of times.  The argument is that Boltzmann brains would occur in high entropy universes (which may be thought of as being common and plentiful, and thus unsurprising) while the evolutions (cosmic and biological) that led to us could only happen in low entropy universes (which may be thought of as being rare and unlikely, and thus surprising).  We then arrive back at a sort of geocentricity-like situation, while our planet is not the centre of the universe, our universe is of a very special type rather than being typical.  From this it is argued that Boltzmann brains (as temporary denizens of the far more common high entropy universes) are more typical than we are, so we should be surprised at not being a Boltzmann brain in a different type of universe.

I disagree.

We have at least one more thing to consider, our persistence.  If we considered only one aspect of ourselves in isolation, that we are conscious and aware, then sure we might be surprised that we are not a Boltzmann brain.  But we are also persistent, we don't dissipate.  And Boltzmann brains will dissipate because, by nature, they are fluctuations in high entropy, thermally flat universes.  They represent a region of low entropy and very argument that leads to them assumes the second law of thermodynamics, that entropy increases.  The Boltzmann brain would necessarily decay, about as quickly as it came into existence, and return to equilibrium.  Absent magic, the Boltzmann brain could not choose to persist, or to replicate itself.

In other words, we are not just a thing (intelligence), we are thing of a particular type (persistent intelligence, noting that a host of other adjectives could be involved).  If I were to say that I am human, and consider only that, then I should be surprised if I was neither Asian nor African (who together make up more than three quarters of the world's population).  But if I were to note that I also have a genetic abnormality (say mutation to the melanocortin-1 receptor on chromosome 16), then I should not be at all surprised if I had pasty white skin, bright red hair, a vile temper and lived in Auchtermuchty (in Fife, Scotland not that far from Ladybank, which sounds like a euphemism - also not that far from St Andrews, ancestral home of "sweary rambling with sticks" (also known as golf)).

Being a persistent intelligence, it should come as no surprise that I am not a Boltzmann brain and for that reason, I think this rather stupid objection to multiverses fails.  (It also fails because, if Boltzmann brains are a problem, they are also a problem for monoverses.)

So, are there any meaningful objections to the multiverse other than Boltzmann brains?  Well, there are three objections from Robin Collins WLC, as summarised here by John Piippo:

For in order to be scientifically credible, some plausible mechanism must be suggested for generating the many worlds. But if the many worlds hypothesis is to be successful in attributing fine-tuning to chance alone, then the mechanism that generates the many worlds had better not be fine-tuned itself. For if it is, then the problem arises all over again: How do you explain the fine-tuning of the multiverse?

(The BGV theorem) requires that even a multiverse of bubble universes must have a beginning. In that case the mechanism that generates the bubble universes has been chugging away for only a finite amount of time. So by now, there may well be only a finite number of bubbles in the world ensemble, which may not be enough to guarantee the appearance of a finely tuned universe by chance alone. There's no evidence that the sort of world ensemble required by the many worlds hypothesis actually exists.

If our world is just a random member of a world ensemble, then it's vastly more probable that we should be observing a much smaller region of order. It turns out that a parallel problem faces the many worlds hypothesis as an explanation of fine-tuning. [Oxford physicist] Roger Penrose has pressed this objection forcefully.

The first objection, re fine-tuning of the multiverse, is merely a caution that a theoretical multiverse, presented as an objection to god as designer, cannot be fine-tuned.  Okay, thanks for that.  It's not really an objection to the multiverse per se and there's no indication that I am aware of that any of the theoretical multiverse necessitate fine-tuning.

The key element in the second objection is that there is no evidence for a multiverse, but thing is that there is evidence, certainly evidence for a multiverse generating process (watch George Efstathiou's comments, indicating that Planck data constitutes evidence in support of eternal inflation).  Even if there were no scientific evidence at all in support of a multiverse, this would not mean that the multiverse would be less supported than the god did it theory.  And with the multiverse theory, there are things that theoreticians can look out for because the theory is testable.

The third argument is actually associated with the Boltzmann brain argument (order and entropy are inextricably linked concepts).  Again, the argument is based on selected aspects of our existence and when we consider the totality of our existence, then we should not be surprised that we live in the sort of universe that we live in since it's clearly a possible universe and it's just the sort of universe that permits intelligence like ours to develop.  This objection seems to miss the point rather spectacularly.

A quite amusing aspect to Collins'  WLC's third objection is the reference to Roger Penrose (note that I changed the link to something more relevant than the Amazon page for The Road to Reality: A Complete Guide to the Laws of the Universe).  In the book that Piippo links to, Penrose mentions the word multiverse on only one page.  According to the index this was on page 783, but I could not find it on that page.  This review indicates that it might be on page 784 (which is not part of the Google Books review).  And the mention of multiverse is only to say that Penrose prefers the word "omnium" to "multiverse", a strange position to take if you are arguing forcefully against the fundamental concept (confirmed).  Additionally, Penrose's conformal cyclical cosmology is a temporal form of a multiverse, with our universe being reset and recycled ad infinitum (and Penrose claimed that circular patterns in the CMB data from WMAP were suggestive of earlier universe, some might claim that they are suggestive of young bubble universes bumping into each other or side-effects of inflation, while others might suggest that some people are just seeing what they want to see).

<edit> The blogger measureoffaith (see comments below) suggests that Penrose forcefully makes the case that multiverses face the same problem with fine-tuning that our universe does in sub-chapter 28.7 The Big Bang’s special nature: an anthropic key?  It would appear, however, that this section must be read very optimistically by a theist, especially when Penrose's conclusion mirrors mine - that it comes down to either design or chance, that god did it or there's some mathematical/scientific reason why the universe is the way it is, and that it's worthwhile investigating the latter.

Robin Collins also presents some objections to the multiverse, in this document.  His objections relate to the nature of a "many-universes generator".  I wrote about these objections in "The Four Mechanisms of the Ignopalypse", but I am holding off on publishing it (or was at time of writing, if you are reading this later).  It should be up later in the year.  For the moment, suffice it to say that I don't find Collins' objections to be meaningful or substantive. <end edit>

If there are any meaningful and substantive objections to multiverse theory, I would be keen to hear of them but so far there seems to be little more than a chorus of appeals to incredulity.

In conclusion, the fine-tuning of the universe can really only be explained by chance or design, since all other objections resolve down to one or the other.  I'm not overly fussed by the nature of the designer, since I don't consider a designer to be the correct answer anyway (for other reasons, quite separate from the theoretical impossibility of design).  That said, given the nature of the design argument, nothing we ever come across will be sufficient to eliminate design as a theoretical possibility - since a designer could have created the universe with the intention to make it totally indistinguishable from a universe that came into existence by chance.  All that we have is a counter to the argument that a designer must exist because there is no other alternative.  We do have an alternative, in the form of a multiverse.

Something that is worth considering, particularly if you are a pro-fine-tuning, anti-multiverse theist, is that science is inching closer and closer to proving that the multiverse is reality, rather than just hypothesis.  If you have nailed your colours to the notion that fine-tuning is a knock-down argument for god because you think that the multiverse might not exist, it is high time that you reconsider your position. (Much as Jeff Zweerink has - listen to the second impressive moment.)

Multiholes in WLC's Physics Arguments

At the end of The Eternally Inflated (Multiverse and WLC), I mentioned reliance "on argumentation from (false) ignorance".  It's a fair question if you were to ask: what the hell is false ignorance.  Let me to clarify.

An appeal to ignorance is a fallacy in which, for example, an apologist might say something like "There is no other known reason why X would happen, therefore god did it" or "You can't prove that god doesn't exist, therefore it does".

What I mean by false ignorance is the sort of move performed by an apologist, where he or she claims ignorance regarding evidence against his or her case, despite that evidence being readily available.  In some cases, the feigned ignorance is all the more egregious because not only is the evidence readily available, but it is a matter of public record (in video and transcript) that the evidence has been presented.

Here are some pertinent examples - all centred on arguments raised by WLC - that are raised by people interviewed by Skydive Phil and co in recent films (look for the tag "Before the Big Bang"):

Misrepresenting The BGV theorem

WLC constantly informs us that the BGV theorem means that the universe had a beginning: (debate with Sean Carroll, March 2014) "In 2003 Arvind Borde, Alan Guth, and Alexander Vilenkin were able to show that any universe which is, on average, in a state of cosmic expansion throughout its history cannot be infinite in the past but must have a beginning."

One of the authors, Alan Guth says that's not correct, the theorem only implies that inflation had a beginning.  While, it is true that Vilenkin has subsequently written an article which concludes that the universe "probably" did have a "beginning", he caveats the term "beginning" so as to be "synonymous to past incompleteness" - so this does not necessarily mean an ex nihilo creation event.

The conclusion to the actual BGV paper is revealing: "Our argument shows that null and time-like geodesics are, in general, past-incomplete in inflationary models, whether or not energy conditions hold, provided only that the averaged expansion condition H_av > 0 holds along these past-directed geodesics. This is a stronger conclusion than the one arrived at in previous work in that we have shown under reasonable assumptions that almost all causal geodesics, when extended to the past of an arbitrary point, reach the boundary of the inflating region of space-time in a finite proper time (finite affine length, in the null case)."

Note the caveats: "in general", "provided that", "under reasonable assumptions", "almost all", "in the null case".  Even if we look past those caveats, we see that the authors are making a claim about a "boundary of the inflating region of space-time".  This says nothing about what did or did not exist prior to that inflation.

Finally, Sean Carroll told WLC this in his rebuttal speech during their debate: "Now there’s a theorem by Alan Guth, Arvind Borde, and Alex Vilenkin that says the universe had a beginning. I’ve explained to you why that’s not true but in case you do not trust me I happen to have Alan Guth right here. One of the authors of the Borde-Guth-Vilenkin Theorem, Alan what do you say? He says, “I don’t know whether the universe had a beginning. I suspect the universe didn’t have a beginning. It’s very likely eternal but nobody knows.” Now how in the world can the author of the Borde-Guth-Vilenkin theorem say the universe is probably eternal? For the reasons I’ve already told you. The theorem is only about classical descriptions of the universe not about the universe itself."

In his February 2016 debate with Kevin Scharp, WLC trotted out his version of the BGV again, claiming it as evidence that universe (or multiverse has an absolute beginning).

Pushing the Past Eternal

WLC claims, for a number of reasons, that the universe cannot be eternal in the past.  One of the authorities that he calls on in support of this claim is Alan Guth.  Guth explains in Before the Big Bang 4 : Eternal Inflation & The Multiverse why he favours models that are past eternal.

Despite WLC's protestations, there are a number of models which are consistent with past eternality: the cyclic model (possibly with one bounce only), conformal cyclic cosmology, loop quantum gravity and dual arrow of time models such as that being worked on by Alan Guth and Sean Carroll.

Therefore, WLC's claims are based on false ignorance.  He has no justification for believing that there are no workable cosmologies that are past eternal.

Boltzmann Brains

I'm not big into Boltzmann brains, for reasons that I plan to write about in the near future.  WLC loves them.  The reason why he loves them, as best as I can see, is that it makes physicists look silly when they take the idea seriously.

However, when WLC raises Boltzmann brains, he does so to discredit the idea of a multiverse (which he sometimes refers to as a "World Ensemble").  The problem that WLC has when does this, as Alan Guth points out, is that Boltzmann brains are a problem even for single universes and the multiverse (particularly the pocket universe solution that creates new pockets of low entropy space-time in which low entropy observers like ourselves could develop) is the solution to that problem.

But even if that weren't the case, the argument as presented by WLC himself is only that high entropy, short-lived Boltzmann brains are more likely than low entropy, slowly developed observers.  There is no claim that we are impossible under the assumptions being presented.  So with a "World Ensemble" theory, it is possible for intelligent life like ours to develop and, therefore, given enough "worlds" in that "ensemble" (as N approaches infinity), the existence of our type of intelligent life within the ensemble becomes a virtual certainty - no matter how unlikely it might be.

Going Low with Entropy

This is in a similar vein to the Boltzmann brain argument, although a whole lot less silly.  WLC claims that the second law of thermodynamics, that entropy tends to increase, implies the universe cannot be past eternal.  Again, this is put to bed by the multiverse, particularly of the sort suggested by Alan Guth and also the Conformal Cyclic Cosmology championed by Penrose, another physicist who has been widely misrepresented on this subject by apologists, including WLC.  Both Guth and Penrose suggest that the solution to the mystery of why the entropy state of the universe was so low prior to the big bang was that there was a "before" the big bang that put the entropy into a relatively low state.

Note that I use the term "relatively", by this I mean to highlight that there is no upper limit to entropy.

Misrepresenting Anthony Aguirre

In his debate with Sean Carroll, WLC selectively used words from Anthony Aguirre and John Kehayias to claim that the universe must have had a beginning:

It is very difficult to devise a system – especially a quantum one – that does nothing ‘forever,’ then evolves. A truly stationary or periodic quantum state, which would last forever, would never evolve, whereas one with any instability will not endure for an indefinite time.

These are taken from the paper "Quantum Instability of the Emergent Universe".  The footnote, provided to the transcript but not presented at the actually debate, clarifies that Aguirre's argument is specific to the Ellis-Maarten model but then claims that "their point is generalizable".

Aguirre himself (in the film) confirms he only claimed that a particular model (the "Emergent Universe” of the paper's title) doesn’t work in creating an eternal past, and he goes on to clarify that other models do work with an eternal past, thus putting a lie to WLC's claim that the point was "generalizable".

Conformal Cyclic Cosmology

In one of his podcasts and in a Q&A response, WLC claims that Penrose's conformal cyclic cosmology (CCC) is not a cyclic model (noting that he shares credit for this argument with James Sinclair and makes a philosophical appeal to Yujin Nagasawa's authority).  The general thrust of the argument centres on the claim that Penrose's model does not describe consecutive cycles of the universe, but rather that the cycles are concurrent, sharing a common beginning.  In Skydive Phil's film of an interview with Roger Penrose, Penrose directly refutes this notion stressing that the conformal cycles of his cosmology do not originate in a common beginning and instead are sequential.

This film was released after WLC made his comments about the CCC model, but it is interesting that Craig has made no effort to modify his position (and this is despite the fact that one of WLC's own domains, the Reasonable Faith Forums, contains links to the film).

Ignoring the Evidence (for Multiverses)

WLC has claimed that there is no evidence for a multiverse, although does temper this appeal to ignorance with claims that if we were living in a multiverse, then we should be swamped by Boltzmann brains (see above).  This approach really needs to be modified now, either by relying more strongly on the rather silly Boltzmann brain argument, or by moving to a position similar to Jeff Zweerink's (fundamentally, he claimed - at least in the linked clip - that no matter whether a multiverse exists or not, the case for christianity will be made stronger).  To be able to make this latter claim, however, will demand a new stratum of false ignorance as WLC and his fellow apologists wilfully ignore the consequences of multiversality.

If WLC were instead to continue to claim that there is no evidence for a multiverse, he would be wilfully ignoring the words of George Efstathiou, one of the world's top observational cosmologists, who gave a press conference for ESA's Planck satellite (and spoke during the film) saying that there is evidence for a multiverse.  Very specifically, there is evidence of inflation and inflation of the sort that very strongly favours a multiverse.

So, in conclusion, what I mean by an appeal to (false) ignorance is the sort of ploy in which an apologist either pretends to not know about inconvenient facts, or protects his argument against contamination by inconvenient facts, and effectively makes a doubly fallacious appeal to ignorance.  WLC seems to have been guilty of this in at least seven cases.

I say "seems" because it's possible that I have been overly harsh and WLC is in the process of fixing his errors.  We will know that to be the case if, in the future, his debates no longer make these appeals to false ignorance.

Either way, a couple of his key arguments are in tatters.