  In the history of quantum mechanics, much has been written about the
double-slit experiment, and much debate as to its interpretation has ensued.
Indeed, to explain the interference patterns for sub-atomic particles,
explanations have been given not only in terms of the principle of
complementarity and wave-particle duality but also in terms of quantum
consciousness and parallel universes. In this paper, the topic will be
discussed from the perspective of spin-coupling in the hope of further
clarification. We will also suggest that this explanation allows for a realist
interpretation of the Afshar Experiment.
