Facing Up by Steven Weinberg, Harvard, 拢17.95, ISBN
067400647X
WHEN St John preached that the truth shall make you free, the truths of
theoretical physics were not what he had in mind. Steven Weinberg believes that
the physicist is the model of a modern truth-seeker and that such truths are
liberating. At least they leave you free not to believe in the Bible, or in
comparable myths and superstitions.
What emerges from the 20 or so essays, written over 15 years, is a passionate
commitment to science as a rational enterprise that reveals our true place in
the Universe. It is not a particularly comfortable place, because of our cosmic
insignificance, but it at least offers the consolations of melancholy. Many will
recall this much from Weinberg鈥檚 earlier books, especially The First Three
Minutes and Dreams of a Final Theory.
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Apart from the hopes for advances in fundamental physical understanding, the
preoccupation of the earlier essays in Facing Up is the effort to sell
the massive, and massively expensive, particle accelerator known as the
Superconducting Super Collider (SSC) to Congress. The later pieces turn to
questions about the status of scientific knowledge raised by critics in other
disciplines鈥攖he so-called social constructivists who, aside from the
clerics, are the cultural adversaries of the book鈥檚 subtitle.
Not that Facing Up is all that adversarial. Weinberg, as well as
being a fine writer, is as committed to being reasonable as to any other value.
He emphasises, for instance, that there is no connection between the demise of
the SSC project and the arguments about the nature of scientific theory. Unlike
some other commentators on the debates the US press dubbed the 鈥渟cience wars鈥�,
he doesn鈥檛 believe Congressmen have heard of social constructivism. He is a good
listener and a careful reader as well as a clear thinker. But if you challenge
one of his core beliefs, you鈥檇 better have a good argument.
These essays are written at different levels for different audiences. In
spite of some repetition, they add up to a revealing composite of the self-image
of physics at the end of the 20th century. Because he coins such neat sentences,
it is easy to misrepresent Weinberg by selective quotation. He does hold that
physics, in some way, is the most fundamental science, that 鈥渢here is a sense in
which everything is explained by the laws of nature and the laws of nature are
what physicists are trying to discover鈥�. Then he immediately says that this is
no threat to the autonomy of other sciences, which deal with complex phenomena
and emergent properties. He is convinced that 鈥渨e scientists usually know truth
when we see it鈥�, while recognising that there may still be philosophical
questions about what truth actually means. The working physicist, you gather,
needs to believe in truth, reality and scientific progress. Otherwise, why spend
your life struggling to fashion better theories? The point of physics is to get
ever closer to the logical order of nature.
Weinberg admits that he cannot prove this. He is just speaking from his own
scientific experience. That experience would be a powerful influence on anyone.
Weinberg鈥檚 unification of the weak nuclear and electromagnetic forces in the
late 1960s was a great achievement. He still believes that it was a step in a
process by which it is gradually revealed that nature is governed by simpler and
simpler laws. The fact that the standard model of fundamental physics has been
more or less stuck ever since has not weakened his conviction that grander
unification will fulfil the historic mission of physics. For the rest of us,
that may remain an open question. But Weinberg certainly convinces us that such
a belief helps persuade a physicist to go to work.