There are many models which have their own proofs. Without wave-particle duality, there would be not electron microscopes. One definition of a wave is the probability of a particle being at a certain time t. This is one topic where Einstein disagrees with de Broglie, who also disagrees with Feynman, and so on, hence the Copenhagen interpretation. They all agree on the differential equations behind the wave-particle model, but their interpretations of the equations are all in violent disagreement. Great topic though

>> ^offsetSammy:

According to Feynman's QED, there's no such thing as "wave-particle duality", it's just all particles. The behavior of the particles, however, is very strange, and that's what accounts for their wave-like characteristics. QED came after Dirac and Schrodinger (it was a refinement of their theories), so I'm not sure why it doesn't get acknowledged in these kinds of discussions.
QED also predicts exactly the results of things like the double slit experiment without ever resorting to the "well the wave collapses into a particle when we observer it" kind of thing.

Well, de Broglie couldn't get past the fact that in Quantum mechanics, the wave-particle behaves differently if there is an observer. Schrodinger's cat confused a lot of physicists, but it was there to prove a point. When people conducted the double-slit experiment, they confirmed Schrodinger's theory, de Broglie's wave theory, and Heisenberg's theory. Here's the cartoon version of the double-slit diffraction experiment: http://www.youtube.com/watch?v=DfPeprQ7oGc&feature=related

But that's not important right now...

In reply to this comment by Payback:
He was also a great admirer of Priscilla Presley's *beaver.