  We consider Bohm's second-order dynamics for arbitrary initial conditions in
phase space. In principle Bohm's dynamics allows for 'extended' nonequilibrium,
with initial momenta not equal to the gradient of phase of the wave function
(as well as initial positions whose distribution departs from the Born rule).
We show that extended nonequilibrium does not relax in general and is in fact
unstable. This is in sharp contrast with de Broglie's first-order dynamics, for
which non-standard momenta are not allowed and which shows an efficient
relaxation to the Born rule for positions. On this basis we argue that, while
de Broglie's dynamics is a tenable physical theory, Bohm's dynamics is not. In
a world governed by Bohm's dynamics there would be no reason to expect to see
an effective quantum theory today (even approximately), in contradiction with
observation.
