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					       Article by Paul Davies in The Daily Telegraph (UK) 21 September 2006

Albert Einstein is famous for remarking that what most interested him was whether God
had any choice in the nature of his creation. By this, Einstein was asking in
characteristically quaint language whether the universe could have been otherwise, or
whether it must inevitably be as it is. Two generations later, Einstein’s rhetorical question
has re-surfaced with a vengeance, and sparked a bitter controversy that has split the
physics community.

At the heart of the row lies the deep problem of the laws of physics: where do they come
from and why do they have the form that they do? These are not normally questions that
scientists ask. But they have been thrown into sharp relief by the work of a heroic band of
theorists struggling to merge all known laws into a unified mathematical scheme, maybe
even a single formula compact enough to wear on a T shirt. A fashionable contender is
string theory, which replaces the traditional notion of a world built from particles with the
claim that little loops of writhing string can explain everything from electrons to the force
of gravity. Meanwhile, dramatic progress in cosmology has enabled astronomers to piece
together the story of the universe back to the first split second after the big bang.

Given these sweeping advances, it isn’t surprising that some scientists are tempted to
move beyond technicalities and tackle the big foundational questions, such as how the
universe came to exist in the first place, and why its laws are mathematical in nature. One
intriguing question above all has received a lot of attention. Scientists have long known
that the existence of life in the universe depends rather delicately on a number of
felicitous coincidences and special factors in fundamental physics and cosmology. Like
Baby Bear’s porridge in the story of Goldilocks, the universe seems to be ‘just right’ for
life. The late British cosmologist Fred Hoyle summed up the Goldilocks enigma with
characteristic pithiness: ‘the universe is a put-up job,’ he once declared.

To appreciate what is involved, imagine playing god and changing a few things around.
In front of you is a Designer Machine complete with a row of knobs. Twiddle this knob
and you make all electrons a bit heavier; twiddle that knob and you make the nuclear
force a bit stronger. According to the standard models of particle physics and cosmology
there are thirty-something such adjustable quantities needed to describe the physical
world. Simple calculations then suggest that meddling with some of the knob settings,
even by a tiny amount, would prove lethal, wrecking any hope that life could emerge in
the universe. For example, if protons – the stuff of nuclear matter – were just a tad
heavier, all else being equal, they would decay into neutrons, and atoms would fall apart.
If the nuclear force were a few per cent different then carbon, the life-giving element,
would never have formed in abundance by nuclear reactions inside stars. In each case,
life as we know it would be impossible. Taking into account many such ‘fine-tunings’ in
physics and cosmology, it looks as if the universe is a fix – a big fix. What is going on?

This is where the knives come out. Some cosmologists, most notably Lord Martin Rees,
President of The Royal Society, believe there is a very natural explanation for the
uncanny bio-friendliness of the universe. What we have all along been calling ‘the



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universe’ is, it seems, nothing of the sort. Rather, it is but an infinitesimal fragment of a
vast and elaborate system of many universes, or distinct cosmic regions, collectively
dubbed ‘the multiverse.’ Crucially, claims Rees, the laws of physics we observe in our
universe are not the same everywhere but are more akin to local by-laws, valid as far as
our instruments can currently probe, but not truly universal. Other universes within the
multiverse will have different laws. Thus a universe over there may be expanding faster
than ours and contain electrons with stronger charges, while in the universe next door
gravity may be a bit weaker or protons a bit heavier. These cosmic-scale variations might
be completely random. The occasional universe would then fall in the ‘Goldilocks zone’
like a winner in a cosmic jackpot, and possess by pure chance laws and properties just
right for life. It would then be no surprise that we perceive a universe so weirdly suited to
our own presence, because we could obviously not find ourselves situated in a
biologically sterile universe.

The multiverse idea isn’t just idle speculation, but is bolstered by discoveries in
subatomic particle physics. As the energy of physical processes is raised – for example,
in particle collisions – so the laws describing the particles’ behaviour tend to become
simpler and mesh neatly together. The greatest particle physics experiment in history was
the big bang that gave birth to the universe 13.7 billion years ago, so it makes sense to
expect the universe to have started out with simple, unified laws. Then, as the universe
expanded and cooled, so the effective, relatively low-energy ‘by-laws’ that we observe in
the lab emerged from the fiery maelstrom. If there are many alternative low-energy laws,
as theory suggests, then it is likely that a sort of cosmic patchwork quilt arose, in which
each patch acquired its own distinctive set of laws. Our universe is buried deep in one
such patch.

If all this seems hard to swallow, some particle physicists – especially string theorists
such as Nobel prizewinner David Gross of the University of California at Santa Barbara –
will heartily agree with you. They have slammed the multiverse explanation of the
Goldilocks enigma in scathing terms, calling it sloppy science and quasi-religious
mumbo-jumbo. The holy grail of particle physics is to produce a final theory of
everything, and the dream is that this theory-to-end-all-theories will leave nothing to
chance. It will nail down completely every aspect of physical law: all particle masses, the
strength of every force, the details of the big bang – each will be precisely determined in
a welter of breathtaking mathematics. According to this ambitious vision, God would
have no choice in the matter (to paraphrase Einstein), because the laws of physics would
be uniquely specified by the theory, with no lassitude to vary from one universe to the
next. The fact that this unique set of laws just happens to permit life would be shrugged
aside as an incidental quirk of no significance.

The multiverse proponents have hit back, however, in turn accusing the string theorists of
promissory triumphalism. So far string theory, or for that matter any other contender for a
final theory of everything, has yet to correctly predict a single particle mass or force
strength. Some cynics have denounced putative theories of everything as in reality
theories of nothing.




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Amid this acrimonious bickering, it is worth asking whether there might be another
explanation for why the universe appears to have been ingeniously rigged in favour of
life. Overlooked in the squabble is the fact that human beings are more than mere
observers of the great cosmic drama. We have also come to understand, at least in part,
how the universe works. Through science and mathematics, we have decoded the hidden
subtext on which nature runs, uncovering the abstract mathematical laws and principles
that underpin all natural phenomena. The multiverse explanation assumes only that we
are observers: we don’t have to comprehend the world we observe. Yet we do.

In the conventional view, the mathematical basis of physical law is left completely
unexplained. On the one hand there is the abstract world of mathematical forms and
equations – a product of the higher human intellect, fashioned by the vagaries of
evolution – and then there are the laws of physics, which conveniently happen to ‘use’
some of this mathematics. A truly unified account of existence would explain how
mathematics and physical law emerge together in a self-consistent, mutually-supporting
scheme. In this approach, life and mind would be integral to the workings of the universe,
and not just a fluky optional extra.

How might such co-emergence work? To date, we can only glimpse an outline. It has
long been known that quantum physics weaves observers into physical reality in a
fundamental way. This connection between observer and observed needs to be extended
to include not just states of the world, but the laws of nature too. New research has
uncovered tantalizing links between cosmology, quantum physics and information
processing, hinting that the laws of physics are more like programs run on the great
cosmic computer than magically pre-existing free-floating rules. The confluence of
computation science, quantum physics and cosmology may finally yield a proper
understanding of the place of mind in the physical world. Then perhaps we would know
the answer to the biggest of the big questions of existence: Why are we here?




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