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Mind, Matter, and Quantum Mechanics by H. Stapp, Springer Verlag, pp
248, £23 The Machine as Metaphor and Tool edited by Hermann Haken,
Anders Karlqvist and Uno Svedin, Springer Verlag, pp 165, £19

Å®ÉúСÊÓƵs and philosophers are still struggling to come to terms with
what quantum physics means. For a generation, the so-called Copenhagen interpretation,
developed by Niels Bohr and colleagues at the University of Copenhagen,
has held sway. This works in the sense that it enables you to predict correctly
the outcome of experiments. But it contains an extraordinary notion – the
idea that at the quantum level things exist only as quantum wave probabilities
until the act of observation by a human mind ‘collapses the wave function’
and temporarily makes things real.

It is by looking at an electron, say, that we make the electron ‘collapse’
to a single point and shout out ‘Here I am!’ As soon as we stop looking,
the electron dissolves into a spreading pool of probability waves again.
You may find this hard to credit. So did Albert Einstein, among others.
And so does Henry Stapp, one of a growing band of researchers trying to
find an alternative interpretation of quantum theory that would fit more
easily with our everyday notions of common sense.

At one level, this search is akin to debating how many angels can dance
on a pinhead. After all, the Copenhagen interpretation works so well that
any alternative explanation must give exactly the same answers in any practicable
experiment. But still, it would be nice if we really understood what goes
on at the quantum level.

Stapp explores what quantum theory and human consciousness are all about
in an effort to find where the interface between common-sense reality and
quantum reality lies. Like John Taylor in his recent book When the Clock
Struck Zero (Picador), Stapp suggests that consciousness is an accumulation
of memory – an awareness of what went before (I do justice to neither author
with this crude simplification of complex arguments, but hope they will
forgive me).

He also discusses the familiar quantum puzzles, like that of Schrodinger’s
cat, and supports a variation on the Copenhagen interpretation developed
by Werner Heisenberg. This says that any macroscopic ‘act of measurement’,
such as recording radioactive decay on a Geiger counter, can collapse a
wave function without human observation. So the cat in the box really is
either dead or alive, not both at once, even before we open the lid to take
a look.

Mind, Matter, and Quantum Mechanics is difficult to read as a book because
it is really a collection of talks and articles pieced together. This involves
several false starts and much repetition. But the repetition, at least,
is welcome in helping to get difficult ideas across.

The Machine as Metaphor and Tool, a multi-author volume that grew out
of a workshop held in Sweden in 1990, is no easy read either. The focus
of the book is again the human brain and consciousness, which highlights
both the advantages and pitfalls of the analogy with machines.

The possibility that the human brain is special, and conscious, because
it operates on the quantum level (familiar from the work of Roger Penrose)
is raised again, but without answering the question this always raises in
my mind, which is why a machine could not be built to operate on the same
quantum principles. Along the way, we meet other metaphors that have proved
useful and dangerous. The way in which our understanding of time has been
altered by the invention of the clock, for example, or the way in which
by describing DNA as carrying a ‘message’, parts of the genome that do not
carry the same kind of message have been emotively labelled ‘junk’.

Whatever the bottom line on human consciousness, though, the bottom
line on ‘realistic’ interpretations of quantum mechanics is that they always
involve inter-actions that travel faster than light, as spelt out by the
theoretical work of the late John Bell and proved by the experiments of
Alain Aspect’s team. It all depends, it seems, on what you mean by ‘common
sense’ and ‘reality’. As well as hating the Copenhagen interpretation, Einstein
also said that ‘the most incomprehensible thing about the Universe is that
it is comprehensible’. Perhaps he was wrong on both counts.