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.
"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 1010(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 1010(123) that
Penrose calls this number “utter chicken feed” in comparison with 1010(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.