The Life of the Cosmos by Lee Smolin, Weidenfeld & Nicolson, 拢20,
ISBN 0297817272
IMAGINE a discussion of Darwin鈥檚 theory of natural selection, Penrose鈥檚
twistor theory, Lovelock and Margulis鈥檚 Gaia hypothesis, Conway鈥檚 Game of Life,
Mandelbrot鈥檚 fractals and Prigogine鈥檚 non-equilibrium thermodynamics, intimately
intertwined with gauge theories in elementary particle physics, string theory,
cosmology, general relativity, quantum mechanics and topological quantum field
theory. Add philosophy, art, theology, politics and sociology, with homage to
the relational view of space and time proposed by Leibnitz in contrast to the
discredited absolute space and time of Newton.
Smolin has the ambitious goal of explaining the problems that confront the
new generation of theoretical physicists and cosmologists, and proposes his own
ideas towards their solution. He has undoubtedly made an impressive sweep across
most of the unanswered questions in fundamental physics, but it is difficult to
form a judgment about the parts of his story with which I have only a passing
familiarity. Let me look first at a part that I am very familiar
with鈥攏amely, elementary particle physics and quantum mechanics.
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Curiously, in his discussion of the standard model of the weak and
electromagnetic interactions, Smolin makes no mention of Sheldon Glashow, the
first to write down such a model and who shared the Nobel prize with Steven
Weinberg and Abdus Salam. The omission of a reference to Glashow seems
significant because Glashow is a well-known opponent of the string theory
approach that Smolin embraces enthusiastically.
Smolin is honest, however, in his account of the present arbitrariness in
string theory and its inability to predict the particle masses we see around us,
along with its lack of 鈥渁ny realistic expectation of soon receiving guidance
from experimental physics鈥�.
The centrepiece is a popular exposition of Smolin鈥檚 Darwinian approach to
cosmology, which he calls 鈥渃osmological natural selection鈥�. The basis for the
theory is the apparent need for the twenty or so parameters of the standard
model to be fine-tuned to an incredible degree of accuracy over a huge range of
magnitudes, so that life, the Galaxy and the Universe can exist at all.
It is widely believed that our Universe contains a huge number of black holes
whose interiors correspond to unobservable regions. According to general
relativity, all matter inside the black hole collapses to a point singularity.
Smolin argues that quantum effects may come into play to remove this singularity
and the collapsing black hole 鈥渂ounces鈥� back into an expansion. Smolin suggests
that inside each black hole is a new expanding Universe with black holes. He
then assumes that the twenty-odd parameters of the standard model change a
little bit at each bounce and, as in Darwinian evolution, the 鈥渇itness
landscape鈥� of all possible universes evolves until universes in which the
parameters correspond to a state of maximal black hole production
predominate.
Supposedly, the theory is testable by playing God and twiddling the set of
parameters we observe in our Universe: we can then attempt to see whether or not
such changes lead to more or less black hole production. Perhaps I am at odds
with a new, postmodernist world, but such 鈥渞andom assumption鈥� physics reminds me
of the once-great University of Salamanca. In the 18th century, only one faculty
set an examination with a single question repeated every year: 鈥淲hat language do
the angels speak?鈥�