Re: big bang problems
- From: Gareth McCaughan <Gareth.McCaughan@xxxxxxxxx>
- Date: Sat, 02 May 2009 02:56:53 +0100
Dianelos Georgoudis wrote:
[Marc Rasell:]
that its a
miracle we are here! Which leaves the question, why are we here, why
not no universe at all?
[me:]
If there were no universe at all, no one would be asking the
question. Why does the earth have (unlike most planets, so
far as we can tell) all the features needed to support life?
Because on the planets that don't, there's no one to ask
such questions.
[Dianelos:]
By the same measure: Why is the Earth's sun as hot as it is? Because
if it were significantly less or more hot then there would be no life
on Earth and nobody to ask this question. - But that's not a valid
answer, is it?
Depends on just what you mean by "why", though the distinction
I have in mind isn't the same one as you mention below.
Explanations (ideally) do two things. (1) They provide understanding
of how something happens, or works, or came to exist, or whatever.
(2) They show that the probability of something was not unreasonably
low, thereby reducing the discomfort we should feel at believing
needlessly improbable things.
"Anthropic" explanations are absolutely hopeless at #1, but work
pretty well for #2, in much the same way as one's feeling of
astonishment at having won the lottery[1] subsides on reflecting
that *someone* generally wins it.
[1] I have never won the lottery. I have never played the
lottery.
Let me say a bit more about #2. Monstrously improbable things
happen all the time. Shuffle a pack of cards and deal out four
13-card hands; I'm too lazy to do the calculations, but whatever
particular set of hands you've dealt is tremendously improbable.
This doesn't usually generate any particular feeling that
something needs explaining. But if you deal the cards and find
that one hand contains all the spades, one all the hearts, etc.,
then you will certainly feel that something needs explaining.
Why? Not because that hand is more improbable than any other!
I think there are two reasons, one good and one bad. The bad
one is simply that when you deal a striking hand like that
your attention is drawn to the particular arrangement of cards
and you notice how improbable it was. (That's got to be a bad
reason, unless you think you should go around in a perpetual
daze of astonishment at every random occurrence in the universe.)
The good one is that for that particular hand (and various others
that you would also be likely to notice) there's *another*
candidate explanation that, while rather unlikely most of the
time, becomes likely in this situation: that someone cheated
somehow. (Not necessarily with malicious intent; it might
have been a joke.)
So. Our brains are very, very good at spotting things that
might be the work of intelligent agents, things that someone
might have a reason to do. And when we think we've spotted
such a thing but not identified the intelligent agent in question,
we feel uneasy. (I think paranoia is the result of the mechanisms
for all this getting just a little overactive.) One heuristic
they use (I think) is: if something benefits someone greatly,
it's likely to be deliberate. Well, the existence of a habitable
universe, or a habitable solar system, does on the whole seem
to be a great benefit -- problems of evil notwithstanding --
so bzzzt! go our intention-detectors, and we feel that something
needs explaining.
If you try to turn that feeling into an *argument*, I think
there's some question-begging involved. (I think you're agreeing
with this when you say that if you take "why?" teleologically,
which is more or less to say personally, then you're asking
a question that only makes sense on theistic assumptions.)
But, anyway, just as winning the lottery is less in need of
explanation (that is, tacitly: explanation in terms of
someone's intentions) once you realise that the number of
people playing it is (necessarily) comparable to the inverse
probability of winning -- because now the fact that needs
explaining, objectively considered, is "someone won" rather
than "*I* won" -- so having a habitable solar system is
less in need of explanation once you realise that the number
of solar systems out there is vast.
(You might still wonder why the sun happens to have the
particular characteristics it does, just as you might
wonder what sequence of random happenings led to your
winning the lottery. But there wouldn't be that feeling
of *needing* an explanation.)
Under the latter meaning of why questions, which is the only one that
makes sense within a naturalistic understanding of reality I still
doubt whether the questions "Why is there a universe in the first
place?" or "Why do the fundamental constant have the values they
have?" are valid questions. After all the naturalist may reasonably
claim that the Big Bang is the uncaused cause of all existence, and
being uncaused does not admit of any further operative explanation.
Within naturalism the Big Bang and its nature can be seen as the rock
bottom level of reality, the ultimate brute facts. I don't know why
the holders of a particular worldview should answer questions that
make no sense within their own worldview.
You've said things like this before, and I've been unconvinced
before. Here's one reason: holding a particular view of the world
is not the same thing as having an unshakeable commitment to
go on holding it. Being an atheist, for instance, doesn't mean
finding it *unthinkable* that the universe might have been
created. Being a theist doesn't mean finding it unthinkable
that it might not. So a question like "For what purpose is the
universe the way it is?" isn't exactly *nonsense* to me; it
just has implicit premises that I disagree with. And given
something sufficiently improbable, it's reasonable to think
that there might be need for more explanation than "that's
just the way things are": if you are at ground zero for a
large nuclear explosion and walk away unharmed, it would
seem rather unsatisfactory to shrug your shoulders and say
"well, if I hadn't survived I wouldn't be here to wonder how,
would I?".
I don't find cosmological fine-tuning arguments convincing,
for reasons some of which we've discussed before. But the
questions raised by people making such arguments aren't,
or at least aren't necessarily, crazy or meaningless even
from an atheist's perspective.
--
Gareth McCaughan
sig under construc
.
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