Why the universe wasn't fine-tuned for life
14 June 2011
Marcus Chown, consultant
In The Fallacy of Fine-tuning, Victor Stenger dismantles arguments that the laws
of physics in our universe were ""fine-tuned" to foster life
IF THE force of gravity were a few per cent weaker, it would not squeeze and
heat the centre of the sun enough to ignite the nuclear reactions that generate
the sunlight necessary for life on Earth. But if it were a few per cent
stronger, the temperature of the solar core would have been boosted so much the
sun would have burned out in less than a billion years - not enough time for the
evolution of complex life like us.
In recent years many such examples of how the laws of physics have been
"fine-tuned" for us to be here have been reported. Some religious people claim
these "cosmic coincidences" are evidence of a grand design by a Supreme Being.
In The Fallacy of Fine-tuning, physicist Victor Stenger makes a devastating
demolition of such arguments.
A general mistake made in search of fine-tuning, he points out, is to vary just
one physical parameter while keeping all the others constant. Yet a "theory of
everything" - which alas we do not yet have - is bound to reveal intimate links
between physical parameters. A change in one may be compensated by a change in
another, says Stenger.
In addition to general mistakes, Stenger deals with specifics. For instance,
British astronomer Fred Hoyle discovered that vital heavy elements can be built
inside stars only because a carbon-12 nucleus can be made from the fusion of
three helium nuclei. For the reaction to proceed, carbon-12 must have an energy
level equal to the combined energy of the three helium nuclei, at the typical
temperature inside a red giant. This has been touted as an example of
fine-tuning. But, as Stenger points out, in 1989, astrophysicist Mario Livio
showed that the carbon-12 energy level could actually have been significantly
different and still resulted in a universe with the heavy elements needed for
life.
The most striking example of fine-tuning appears to be the dark energy - or
energy of the vacuum - that is speeding up the expansion of the universe.
Calculations show it to be 10120 bigger than quantum theory predicts. But
Stenger stresses that this prediction is made in the absence of a quantum theory
of gravity, when gravity is known to orchestrate the universe.
Even if some parameters turn out to be fine-tuned, Stenger argues this could be
explained if ours is just one universe in a "multiverse" - an infinite number of
universes, each with different physical parameters. We would then have ended up
in the one where the laws of physics are fine-tuned to life because, well, how
could we not have?
Religious people say that, by invoking a multiverse, physicists are going to
extraordinary lengths to avoid God. But physicists have to go where the data
lead them. And, currently, there are strong hints from string theory, the
standard picture of cosmology and fine-tuning itself to suggest that the
universe we can see with our biggest telescopes is only a small part of all that
is there.
Victor J Stenger on June 14, 2011 7:00 PM
I am sure it was unintentional, but unfortunately Marcus Chown's too-short
review has given the impression that my case against fine-tuning is based on
some still unknown theory-of-everything. Quite the contrary. It is based solely
on well-established physics and cosmology. It also does not depend on the
multiverse hypothesis. Some of the parameters claimed to be fine-tuned are even
fixed by current theories. Others have possible variations that are well within
the range for allowing some from of complex life.
Please read the book. Do no make judgments on any book based only on reviews.
MY COMMENT:
When we mammals all vanish and only beetles and volcanic worms are around will they be saying the universe is fine-tuned for them?
