  An interpretation of quantum mechanics is proposed which augments the
stochastic pilot-wave model, introduced by Nelson [E. Nelson, Phys. Rev., 150,
1079 (1966)], with a dual guidance condition. Namely, in addition to the
stochastic guidance condition which describes how the wave controls the
particle (wave-to-particle guidance condition), we introduce another stochastic
guidance condition describing how the particle guides the wave
(particle-to-wave guidance condition). We therefore introduce an
action-reaction principle in the pilot-wave formulation of quantum mechanics.
The particle-to-wave guidance condition takes the form of spontaneous
transitions of the wavefunction that are Poisson distributed in time. The
wavefunction selected by the transition is influenced by its likelyhood with
respect to the particle position, as well as certain conservation constraints.
It is shown that the stochastic particle-to-wave guidance condition reproduces
certain aspects of the spontaneous localization model of Ghirardi, Rimini and
Weber [G. C. Ghirardi, A. Rimini and T. Weber, Phys. Rev. D, 34, 470 (1986)],
and of Milburn's intrinsic decoherence model [G. J. Milburn, Phys. Rev. A, 44,
5401 (1991)], while avoiding some of the difficulties associated with them. The
macroscopic limit of the dualist interpretation is analyzed for the case of a
free body. Possible improvements of this interpretation are discussed.
