Paul Davies on the Goldilocks enigma
Rebecca Lann
fixed it http://www.guardian.co.uk/comment/story/0,,2111345,00.html
[We will never explain the cosmos by taking on faith either divinity
or physical laws. True meaning is to be found within nature]
by Paul Davies -- Scientists are slowly waking up to an inconvenient
truth - the universe looks suspiciously like a fix. The issue concerns
the very laws of nature themselves. For 40 years, physicists and
cosmologists have been quietly collecting examples of all too
convenient "coincidences" and special features in the underlying laws
of the universe that seem to be necessary in order for life, and hence
conscious beings, to exist. Change any one of them and the
consequences would be lethal. Fred Hoyle, the distinguished
cosmologist, once said it was as if "a super- intellect has monkeyed
with physics".
To see the problem, imagine playing God with the cosmos. Before you is
a designer machine that lets you tinker with the basics of physics.
Twiddle this knob and you make all electrons a bit lighter, twiddle
that one and you make gravity a bit stronger, and so on. It happens
that you need to set thirtysomething knobs to fully describe the world
about us. The crucial point is that some of those metaphorical knobs
must be tuned very precisely, or the universe would be sterile.
Example: neutrons are just a tad heavier than protons. If it were the
other way around, atoms couldn't exist, because all the protons in the
universe would have decayed into neutrons shortly after the big bang.
No protons, then no atomic nucleuses and no atoms. No atoms, no
chemistry, no life. Like Baby Bear's porridge in the story of
Goldilocks, the universe seems to be just right for life. So what's
going on?
The intelligent design movement has inevitably seized on the
Goldilocks enigma as evidence of divine providence, prompting a
scientific backlash and boosting the recent spate of God-bashing
bestsellers.
Fuelling the controversy is an unanswered question lurking at the very
heart of science - the origin of the laws of physics. Where do they
come from? Why do they have the form that they do? Traditionally,
scientists have treated the laws of physics as simply "given", elegant
mathematical relationships that were somehow imprinted on the universe
at its birth, and fixed thereafter. Inquiry into the origin and nature
of the laws was not regarded as a proper part of science.
But the embarrassment of the Goldilocks enigma has prompted a rethink.
The Cambridge cosmologist Martin Rees, president of The Royal Society,
suggests the laws of physics aren't absolute and universal but more
akin to local bylaws, varying from place to place on a mega-cosmic
scale. A God's-eye view would show our universe as merely a single
representative amid a vast assemblage of universes, each with its own
bylaws. Rees calls this system "the multiverse", and it is an
increasingly popular idea among cosmologists. Only rarely within the
variegated cosmic quilt will a universe possess bio-friendly laws and
spawn life. It would then be no surprise that we find ourselves in a
universe apparently customised for habitation; we could hardly exist
in one where life is impossible. If Rees is right, the impression of
design is illusory: our universe has simply hit the jackpot in a
gigantic cosmic lottery. The multiverse theory certainly cuts the
ground from beneath intelligent design, but it falls short of a
complete explanation of existence. For a start, there has to be a
physical mechanism to make all those universes and allocate bylaws to
them. This process demands its own laws, or meta-laws. Where do they
come from? The problem has simply been shifted up a level from the
laws of the universe to the meta-laws of the multiverse.
The root cause of all the difficulty can be traced to the fact that
both religion and science appeal to some agency outside the universe
to explain its lawlike order. Dumping the problem in the lap of a pre-
existing designer is no explanation at all, as it merely begs the
question of who designed the designer. But appealing to a host of
unseen universes and a set of unexplained meta-laws is scarcely any
better.
This shared failing is no surprise, because the very notion of
physical law has its origins in theology. The idea of absolute,
universal, perfect, immutable laws comes straight out of monotheism,
which was the dominant influence in Europe at the time science as we
know it was being formulated by Isaac Newton and his contemporaries.
Just as classical Christianity presents God as upholding the natural
order from beyond the universe, so physicists envisage their laws as
inhabiting an abstract transcendent realm of perfect mathematical
relationships. Furthermore, Christians believe the world depends
utterly on God for its existence, while the converse is not the case.
Correspondingly, physicists declare that the universe is governed by
eternal laws, but the laws remain impervious to events in the universe.
I think this entire line of reasoning is now outdated and simplistic.
We will never fully explain the world by appealing to something
outside it that must simply be accepted on faith, be it an unexplained
God or an unexplained set of mathematical laws. Can we do better? Yes,
but only by relinquishing the traditional idea of physical laws as
fixed, perfect relationships. I propose instead that the laws are more
like computer software: programs being run on the great cosmic
computer. They emerge with the universe at the big bang and are
inherent in it, not stamped on it from without like a maker's mark.
Man-made computers are limited in their performance by finite
processing speed and memory. So, too, the cosmic computer is limited
in power by its age and the finite speed of light. Seth Lloyd, an
engineer at MIT, has calculated how many bits of information the
observable universe has processed since the big bang. The answer is
one followed by 122 zeros. Crucially, however, the limit was smaller
in the past because the universe was younger. Just after the big bang,
when the basic properties of the universe were being forged, its
information capacity was so restricted that the consequences would
have been profound.
Here's why. If a law is a truly exact mathematical relationship, it
requires infinite information to specify it. In my opinion, however,
no law can apply to a level of precision finer than all the
information in the universe can express. Infinitely precise laws are
an extreme idealisation with no shred of real world justification. In
the first split second of cosmic existence, the laws must therefore
have been seriously fuzzy. Then, as the information content of the
universe climbed, the laws focused and homed in on the life-
encouraging form we observe today. But the flaws in the laws left
enough wiggle room for the universe to engineer its own bio-
friendliness.
Thus, three centuries after Newton, symmetry is restored: the laws
explain the universe even as the universe explains the laws. If there
is an ultimate meaning to existence, as I believe is the case, the
answer is to be found within nature, not beyond it. The universe might
indeed be a fix, but if so, it has fixed itself.
Guardian Unlimited (c) Guardian News and Media Limited 2007
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