The GOD Delusion (22 page)

An
example of Rees's six numbers is the magnitude of the so-called
'strong' force, the force that binds the components of an atomic
nucleus: the nuclear force that has to be overcome when one 'splits'
the atom. It is measured as E, the proportion of the mass of a hydrogen
nucleus that is converted to energy when hydrogen fuses to form helium.
The value of this number in our universe is 0.007, and it looks as
though it had to be very close to this value in order for any chemistry
(which is a prerequisite for life) to exist. Chemistry as we know it
consists of the combination and recombination of the ninety or so
naturally occurring elements of the periodic table. Hydrogen is the
simplest and commonest of the elements. All the other elements in the
universe are made ultimately from hydrogen by nuclear fusion. Nuclear
fusion is a difficult process which occurs in the intensely hot
conditions of the interiors of stars (and in hydrogen bombs).
Relatively small stars, such as our sun, can make only light elements
such as helium, the second lightest in the periodic table after
hydrogen. It takes larger and hotter stars to develop the high
temperatures needed to forge most of the heavier elements, in a cascade
of nuclear fusion processes whose details were worked out by Fred Hoyle
and two colleagues (an achievement for which, mysteriously, Hoyle was
not given a share of the Nobel Prize received by the others). These big
stars may explode as supernovas, scattering their materials, including
the elements of the periodic table, in dust clouds. These dust clouds
eventually condense to form new stars and planets, including our own.
This is why Earth is rich in elements over and above the ubiquitous
hydrogen: elements without which chemistry, and life, would be
impossible.

The
relevant point here is that the value of the strong force crucially
determines how far up the periodic table the nuclear fusion cascade
goes. If the strong force were too small, say 0.006 instead
of 0.007, the universe would contain nothing but hydrogen, and no
interesting chemistry could result. If it were too large, say 0.008,
all the hydrogen would have fused to make heavier elements. A chemistry
without hydrogen could not generate life as we know it. For one thing,
there would be no water. The Goldilocks value -0.007 - is just right
for yielding the richness of elements that we need for an interesting
and life-supporting chemistry.

I
won't go through the rest of Rees's six numbers. The bottom line for
each of them is the same. The actual number sits in a Goldilocks band
of values outside which life would not have been possible. How should
we respond to this? Yet again, we have the theist's answer on the one
hand, and the anthropic answer on the other. The theist says that God,
when setting up the universe, tuned the fundamental constants of the
universe so that each one lay in its Goldilocks zone for the production
of life. It is as though God had six knobs that he could twiddle, and
he carefully tuned each knob to its Goldilocks value. As ever, the
theist's answer is deeply unsatisfying, because it leaves the existence
of God unexplained. A God capable of calculating the Goldilocks values
for the six numbers would have to be at least as improbable as the
finely tuned combination of numbers itself, and that's very improbable
indeed -which is indeed the premise of the whole discussion we are
having. It follows that the theist's answer has utterly failed to make
any headway towards solving the problem at hand. I see no alternative
but to dismiss it, while at the same time marvelling at the number of
people who can't see the problem and seem genuinely satisfied by the
'Divine Knob-Twiddler' argument.

Maybe
the psychological reason for this amazing blindness has something to do
with the fact that many people have not had their consciousness raised,
as biologists have, by natural selection and its power to tame
improbability. J. Anderson Thomson, from his perspective as an
evolutionary psychiatrist, points me to an additional reason, the
psychological bias that we all have towards personifying inanimate
objects as agents. As Thomson says, we are more inclined to mistake a
shadow for a burglar than a burglar for a shadow. A false positive
might be a waste of time. A false negative could be fatal. In a letter
to me, he suggested that, in our ancestral past, our greatest challenge
in our environment came from each other. 'The legacy of that is the
default assumption, often fear, of human
intention. We have a great deal of difficulty seeing anything other
than
human
causation.' We naturally generalized
that to divine intention. I shall return to the seductiveness of
'agents' in Chapter 5.

Biologists,
with their raised consciousness of the power of natural selection to
explain the rise of improbable things, are unlikely to be satisfied
with any theory that evades the problem of improbability altogether.
And the theistic response to the riddle of improbability is an evasion
of stupendous proportions. It is more than a restatement of the
problem, it is a grotesque amplification of it. Let's turn, then, to
the anthropic alternative. The anthropic answer, in its most general
form, is that we could only be discussing the question in the kind of
universe that was capable of producing us. Our existence therefore
determines that the fundamental constants of physics had to be in their
respective Goldilocks zones. Different physicists espouse different
kinds of anthropic solutions to the riddle of our existence.

Hard-nosed
physicists say that the six knobs were never free to vary in the first
place. When we finally reach the long-hoped-for Theory of Everything,
we shall see that the six key numbers depend upon each other, or on
something else as yet unknown, in ways that we today cannot imagine.
The six numbers may turn out to be no freer to vary than is the ratio
of a circle's circumference to its diameter. It will turn out that
there is only one way for a universe to be. Far from God being needed
to twiddle six knobs, there are no knobs to twiddle.

Other
physicists (Martin Rees himself would be an example) find this
unsatisfying, and I think I agree with them. It is indeed perfectly
plausible that there is only one way for a universe to be. But why did
that one way have to be such a set-up for our eventual evolution? Why
did it have to be the kind of universe which seems almost as if, in the
words of the theoretical physicist Freeman Dyson, it 'must have known
we were coming'? The philosopher John Leslie uses the analogy of a man
sentenced to death by firing squad. It is just possible that all ten
men of the firing squad will miss their victim. With hindsight, the
survivor who finds himself in a position to reflect upon his luck can
cheerfully say, 'Well, obviously they all missed, or I wouldn't be here
thinking about it.'

But
he could still, forgivably, wonder why they all missed, and toy with
the hypothesis that they were bribed, or drunk.

This
objection can be answered by the suggestion, which Martin Rees himself
supports, that there are many universes, co-existing like bubbles of
foam, in a 'multiverse' (or 'megaverse', as Leonard Susskind prefers to
call it).* The laws and constants of any one universe, such as our
observable universe, are by-laws. The multi-verse as a whole has a
plethora of alternative sets of by-laws. The anthropic principle kicks
in to explain that we have to be in one of those universes (presumably
a minority) whose by-laws happened to be propitious to our eventual
evolution and hence contemplation of the problem.

*
Susskind (2006) gives a splendid advocacy of the anthropic principle in
the megaverse. He says the idea is hated by most physicists. I can't
understand why. I think it is beautiful - perhaps because my
consciousness has been raised by Darwin.

An
intriguing version of the multiverse theory arises out of
considerations of the ultimate fate of our universe. Depending upon the
values of numbers such as Martin Rees's six constants, our universe may
be destined to expand indefinitely, or it may stabilize at an
equilibrium, or the expansion may reverse itself and go into
contraction, culminating in the so-called 'big crunch'. Some big crunch
models have the universe then bouncing back into expansion, and so on
indefinitely with, say, a 20-billion-year cycle time. The standard
model of our universe says that time itself began in the big bang,
along with space, some 13 billion years ago. The serial big crunch
model would amend that statement: our time and space did indeed begin
in our big bang, but this was just the latest in a long series of big
bangs, each one initiated by the big crunch that terminated the
previous universe in the series. Nobody understands what goes on in
singularities such as the big bang, so it is conceivable that the laws
and constants are reset to new values, each time. If
bang-expansion-contraction-crunch cycles have been going on for ever
like a cosmic accordion, we have a serial, rather than a parallel,
version of the multiverse. Once again, the anthropic principle does its
explanatory duty. Of all the universes in the series, only a minority
have their 'dials' tuned to biogenic conditions. And, of course, the
present universe has to be one of that minority, because we are in it.
As it turns out, this serial version of the multiverse must now be
judged less likely than it once was, because recent
evidence is starting to steer us away from the big crunch model. It now
looks as though our own universe is destined to expand for ever.

Another
theoretical physicist, Lee Smolin, has developed a tantalizingly
Darwinian variant on the multiverse theory, including both serial and
parallel elements. Smolin's idea, expounded in
The Life of
the Cosmos,
hinges on the theory that daughter universes are
born of parent universes, not in a fully fledged big crunch but more
locally in black holes. Smolin adds a form of heredity: the fundamental
constants of a daughter universe are slightly 'mutated' versions of the
constants of its parent. Heredity is the essential ingredient of
Darwinian natural selection, and the rest of Smolin's theory follows
naturally. Those universes that have what it takes to 'survive' and
'reproduce' come to predominate in the multiverse. 'What it takes'
includes lasting long enough to 'reproduce'. Because the act of
reproduction takes place in black holes, successful universes must have
what it takes to make black holes. This ability entails various other
properties. For example, the tendency for matter to condense into
clouds and then stars is a prerequisite to making black holes. Stars
also, as we have seen, are the precursors to the development of
interesting chemistry, and hence life. So, Smolin suggests, there has
been a Darwinian natural selection of universes in the multiverse,
directly favouring the evolution of black hole fecundity and indirectly
favouring the production of life. Not all physicists are enthusiastic
about Smolin's idea, although the Nobel Prize-winning physicist Murray
Gell-Mann is quoted as saying: 'Smolin? Is he that young guy with those
crazy ideas? He may not be wrong.'
⁷⁰
A
mischievous biologist might wonder whether some other physicists are in
need of Darwinian consciousness-raising.

It
is tempting to think (and many have succumbed) that to postulate a
plethora of universes is a profligate luxury which should not be
allowed. If we are going to permit the extravagance of a multiverse, so
the argument runs, we might as well be hung for a sheep as a lamb and
allow a God. Aren't they both equally un-parsimonious ad hoc
hypotheses, and equally unsatisfactory? People who think that have not
had their consciousness raised by natural selection. The key difference
between the genuinely extravagant
God hypothesis and the apparently extravagant multi-verse hypothesis is
one of statistical improbability. The multiverse, for all that it is
extravagant, is simple. God, or any intelligent, decision-taking,
calculating agent, would have to be highly improbable in the very same
statistical sense as the entities he is supposed to explain. The
multiverse may seem extravagant in sheer
number
of
universes. But if each one of those universes is simple in its
fundamental laws, we are still not postulating anything highly
improbable. The very opposite has to be said of any kind of
intelligence.

Some
physicists are known to be religious (Russell Stannard and the Reverend
John Polkinghorne are the two British examples I have mentioned).
Predictably, they seize upon the improbability of the physical
constants all being tuned in their more or less narrow Goldilocks
zones, and suggest that there must be a cosmic intelligence who
deliberately did the tuning. I have already dismissed all such
suggestions as raising bigger problems than they solve. But what
attempts have theists made to reply? How do they cope with the argument
that any God capable of designing a universe, carefully and
foresightfully tuned to lead to our evolution, must be a supremely
complex and improbable entity who needs an even bigger explanation than
the one he is supposed to provide?

The
theologian Richard Swinburne, as we have learned to expect, thinks he
has an answer to this problem, and he expounds it in his book 7s
There
a God?.
He begins by showing that his heart is in the right
place by convincingly demonstrating why we should always prefer the
simplest hypothesis that fits the facts. Science explains complex
things in terms of the interactions of simpler things, ultimately the
interactions of fundamental particles. I (and I dare say you) think it
a beautifully simple idea that all things are made of fundamental
particles which, although exceedingly numerous, are drawn from a small,
finite set of
types
of particle. If we are
sceptical, it is likely to be because we think the idea too simple. But
for Swinburne it is not simple at all, quite the reverse.