Science: Martial arts students influence the past

27 August 1994

An American physicist has committed the ultimate sin of taking one scientific
heresy and compounding it with another. The result is an extraordinary
paper that connects the paranormal with quantum theory, the theory that
describes the microscopic world (Physical Review A, July).

Henry Stapp of the University of California at Berkeley has found a
way of modifying the basic equations of quantum theory to permit people
to influence things that happened in the past. Stapp says he was prompted
by the work of Helmut Schmidt, a paranormal investigator who carried out
some controversial experiments two years ago in San Antonio, Texas.

In these tests, a radioactive decay counter was used to generate a sequence
of positive and negative random numbers that no one saw. Several months
later, the two sets of numbers were presented on an elec-tronic display
to martial arts students. The students were asked to influence the statistics
of these num-bers to favour the output of positive ones – all by simple
‘mind power’. Elaborate precautions were taken to prevent any cheating.
Remarkably, the results revealed a significant positive bias in the numbers,
one that had a less than 1 in 1000 probability of occurring by chance.

Could it be that the martial arts students really were influencing the
outcome of radioactive decays recorded months before? Stapp, while acknowledging
the inherent heresy of the idea, thought it worth further consideration.
One reason for his interest was that he acted as an independent monitor
of Schmidt’s experiments.


Stapp’s idea has been to build on a modification of quantum theory first
proposed by Steven Weinberg of the University of Texas at Austin. In 1989,
Weinberg tried introducing a ‘nonlinear’ term into the equations of quantum
mechanics to see how viable a modified version of the theory would be. Nonlinearity
is a common feature of the equations that describe the everyday world,
whether the rupture of an elastic band or the collapse of the stock market.
In a nonlinear equation, the individual terms interact with each other.
Yet, according to quantum theory, the behaviour of the underlying atomic
systems should be perfectly linear, with each term uninfluenced by any other.
Although, most physicists assume the difference arises somewhere in the
gulf between the microscopic and macroscopic worlds, some doubts still linger.
Weinberg wondered whether there was any way of generalising quantum theory
to include possible nonlinear effects.

Eventually, he concluded that when you start tinkering with what is
a supremely elegant theory the whole thing falls apart. Small changes in
quantum theory lead to logical absurdities. But now Stapp has sidestepped
some of Weinberg’s concerns, and come up with his own version of a nonlinear
quantum theory, which he says could explain Schmidt’s parapsychological

The additional nonlinearity, Stapp claims, would allow mental states
to influence the outcome of quantum measurements. ‘Although quantum theory
is a beautiful theory and has been tested to very high accuracy experimentally,
there is still considerable doubt over what precisely happens when a quantum
system such as a decaying radioactive atom is subjected to a measurement,’
says Stapp. ‘Eugene Wigner suggested that consciousness is involved in a
fundamental way. I don’t know whether he was right but if he was then this
work takes his ideas one step further.’

According to quantum theory, a radioactive atom is in a superposition
of states – a mixture of one state in which the atom has decayed and the
other in which it has not. Wigner’s idea was that only when the decay is
monitored by a human observer is the atom forced into one state or the other.
If so, when Schmidt’s radioactive decay counter generates random numbers,
there would actually be a superposition of states each containing different
sets of numbers. Provided no one looked at these numbers, the superposition
would remain indefinitely. In Schmidt’s experiments it would have lasted
until the martial arts students watched their electronic display.

Even accepting the Wigner interpretation, which many physicists do not,
conventional quantum mechanics would still predict that the outcome should
have been unbiased. Contrary to Schmidt’s findings, there should have been
an equal number of positive and negative numbers. However, in Stapp’s modified
version of quantum mechanics, the nonlinear term allows mental states to
skew the relative probabilities. Intent, he says, could boost the chances
of one particular set of numbers being selected over another.

The reason is that if you assume that consciousness is crucial in collapsing
the superposition of states onto one state, to model this process mathematically
you need to include terms in the quantum equations that represent both the
superposition of numbers and the quantum state of the person’s brain. When
one of the martial arts students saw a signal on the display, for example,
the combined system of numbers and brain would have evolved into a new quantum
state. In Stapp’s version of quantum theory, the way this evolution occurs
would depend on a term that involved the interaction of the two – the numbers
and the brain. It is this term that could allow the probabilities to be

In response to the work, Weinberg said he had not seen the paper so
he was unable to comment on its details. However, he pointed out that there
is evidence from measurements of nuclear spin that any nonlinear effects
in quantum mechanics could not contribute more than one part in 1027 of
the energy of a nucleus. ‘That’s a fantastic level of precision. Any modification
of the theory is going to find it difficult to meet that constraint. Furthermore,
another problem with nonlinear terms is that they allow the possibility
of signals that can propagate faster than light. That to me just seems unacceptable.’

In response, Stapp says that he had yet to work out how large an effect
his nonlinear term has on energy levels in the nucleus. However, he thinks
the problem of signalling that is faster than light, which would cause a
breakdown of causality, is linked to the apparent violation of causality
seen in Schmidt’s data. On the face of it, the martial arts students were
able to influence the past. But with Stapp’s theory the whole process remains