198 The Poetry of Physics and The Physics of Poetry
proposal would avoid the uncertainty in momentum, however, in order to
direct the photons equally on all sides one would have to know the
position of the particle. If we could do this we wouldn’t have to make the
measurement in the first place.
The uncertainty principle is not really such a mysterious concept. In
simple terms, it states that in order to obtain information about a system,
it is necessary to disturb the system making it impossible to ever obtain a
complete set of information about the system. To know something is to
interact with it and hence, change it. If we apply this concept to other
areas of human study it will seem even less mysterious. Let us consider
the problem of a biologist studying the behaviour of a group of animals.
The biologist is well aware that his observations will be contaminated to
some extent since the animals will be aware of being observed and
behave differently than they would in a total state of nature. One can
minimize the effects of such observations. Jane Goodall’s observations
of chimpanzees made while she lived in the wilds with her subjects is far
more accurate than those made by observing chimpanzees in a zoo. In
spite of all her care and trouble, the behaviour of the chimpanzees
observed by Jane Goodall was still influenced to some extent by her
presence. The concept of the uncertainty principle can also be applied to
interpersonal relations. If I want to get to know a person, then I must
interact with them and hence, change them to some extent.
The limitations of the physicists’ knowledge of his physical world
arise more or less for the same reason that they arise in the field of
biology of interpersonal relations. To know something is to interact with
it and hence, disturb it. Perhaps the same reason that so many people
(both scientist and lay people) find the uncertainty principle so disturbing
is that a myth has developed surrounding physics. As a result of the
success of Newtonian physics people began to believe that the physicists
were able to provide an exact mathematical description of the physical
world. The success of the post-Newtonian physics in describing other
physical phenomenon such as electricity, magnetism, heat, sound and
light help to reinforce this myth. Thus, it was a great shock to scientists
and non-scientists alike when the study of atomic physics revealed that
there are limitations to man’s knowledge. We shall return to some of the
philosophical implications of the uncertainty principle raised here but let
us first examine its implications for physics.
In classical or Newtonian physics it is possible to determine the exact
position and momentum of a body. Once this information is known