www.newscientist.com 19 August 2006 | NewScientist | 47

■ ONE of the most scandalously

bad misrepresentations of

physics in recent years is the

drama-documentary What the Bleep Do We Know?, released in

2004. The film promulgated the

idea that according to quantum

theory, you can change everyday

reality simply by thinking about it.

In the fictional story, the main

character successfully uses this

mind-over-matter technique to

thin her thighs. Depressingly, it is

the fifth-biggest-grossing

documentary in the US.

The irony here is that the true

world revealed by quantum

theory – which remains our best

description of the microscopic

world of atoms – is far wilder than

anything in the movie. It is a world

where an atom can be in two places

at once – the equivalent of you

being in London and Tokyo

simultaneously. This is not some

theoretical fantasy: it is possible

to observe an atom in two places at

once, or at least the consequences

of this. It’s a world where one

atom can influence another

instantaneously even if they are on

opposite sides of the universe.

This property was deemed so

outrageous by Einstein that he held

it up as proof that quantum theory

was not nature’s last word on

reality (though experiments

appear to show that Einstein was

wrong). Furthermore, it’s a world

where things happen for absolutely

no reason at all, where events are

irreducibly random in a way utterly

unlike the pseudo-random roll of a

die in the everyday world.

This quantum weirdness is

expounded clearly by physicists

Bruce Rosenblum and Fred

Kuttner, who teach a course on

these fundamental ideas at the

University of California, Santa

Cruz. Indeed, the bulk of their

book Quantum Enigma serves as

an entertaining primer on the

nuts and bolts of quantum theory.

However, what principally

interests the authors is not

quantum theory’s fantastically

successful recipe for prediction,

but what the theory “means”. This

takes them to the boundary of

physics and philosophy: the

observer-created reality.

An atom does not travel

through space along a single path

with 100 per cent certainty as a

planet does. Rather, it has a large

number of possible paths open to

it, each with a particular

probability. When the atom is

“observed”, one and only one of

the possibilities is actualised.

Thus, reality is created by

observation. Here the authors

make their most controversial

assertion: that the observer must

be conscious. Consciousness, they

believe, is intimately tied up with

quantum processes.

Many physicists think that the

phenomenon of “decoherence”

does away with the need for a

conscious observer. Decoherence

explains why an atom on its own

can do many things at once, while

entities composed of many atoms,

such as humans, cannot. This is

because in a large collection of

atoms it is impossible for the

quantum waves associated with

each to overlap sufficiently (a state

known as “coherence”) to allow

them to interfere – the key behind

all quantum weirdness. Some

believe a conscious observer is not

necessary for decoherence to take

place. However, Rosenblum and

Kuttner point out that while

decoherence explains why you

and I are never in two places at

once, it does not explain why a

single atom is in one place rather

than another. For an atom to

become fixed, a conscious

observer is essential, they argue.

Rosenblum and Kuttner thus

tie together two great mysteries:

consciousness, and the “quantum

enigma” of how reality coalesces

out of the fog of quantum

possibilities. They never spell out

what they think the connection is,

they only emphasise that it is an

enigma at the heart of quantum

theory that physicists must

sooner or later confront head-on.

They also remind us that we have

not got to the bottom of quantum

theory by a long chalk. We still

need a new way of seeing and, as

quantum philosopher John Bell

said, “The new way of seeing will

involve an imaginative leap that

will astonish us.” ●

Marcus Chown is the author of The Quantum Zoo (Joseph Henry Press, 2006)

What the…? if ever a movie sold quantum theory short it was this one

Quantum Enigma: Physics encounters consciousness by Bruce Rosenblum and Fred Kuttner, OUP, $29.95, ISBN 019517559X

“It’s a world where things happen for absolutely no reason”

Review

WHERE MIND MEETS MATTER

Marcus Chown is intrigued by a new take on what quantum theory really means – something we still don’t understand despite its success in getting to grips with the subatomic world

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