  We assume that particles are point-like objects even when not observed. We
report on the consequences of our assumption within the realm of quantum
theory. An important consequence is the necessity of vacuum fields to account
for particle dynamics. The zero-point energy is evidence of the reality of
vacuum fields. The dynamics of vacuum fields depends on wave equations,
boundary conditions and external sources. The wavefunction is an expression of
vacuum fields. Particle events are described by probabilistic distribution
functions obtained from vacuum fields. We solve the measurement problem by
noticing that in our model the wavefunction does not collapse.
