  In contrast to orthodox quantum mechanics and the GRW/Pearle collapse models, in Bohm's theory wave functions always evolve according to the Schrödinger equation, and thus they never collapse. Wave functions do not represent the states of systems. Rather, they are states of a ‘quantum field (on configuration space)’ that influences the states of  systems.[14]  Also, particles always have definite positions, and the positions of the particles and their wave function at a certain time jointly determine the trajectories of the particles at all future times. Thus, particles’ positions and their wave function determine the outcomes of any measurements (so long as these outcomes are recorded in the positions of some physical systems, as in any practical measurements).