  In this article, I would like to express some of my views on the nature of
turbulence. These views are mainly drawn from the author's recent results on
chaos in partial differential equations \cite{Li04}.
  Fluid dynamicists believe that Navier-Stokes equations accurately describe
turbulence. A mathematical proof on the global regularity of the solutions to
the Navier-Stokes equations is a very challenging problem. Such a proof or
disproof does not solve the problem of turbulence. It may help understanding
turbulence. Turbulence is more of a dynamical system problem. Studies on chaos
in partial differential equations indicate that turbulence can have Bernoulli
shift dynamics which results in the wandering of a turbulent solution in a fat
domain in the phase space. Thus, turbulence can not be averaged. The hope is
that turbulence can be controlled.
