  The dynamical property of the Tsallis distribution is studied from a
Fokker-Planck equation. For the Langevin dynamical system with an arbitrary
potential function, Markovian friction and Gaussian white noise, we show that
no possible nonequilibrium dynamics can use the Tsallis distribution for the
statistical description. The current form of the Tsallis distribution stands
for a simple isothermal situation with no friction and no noise.
