Originally Posted by ozziemate
The same, or something similar, can of course be said of every scientific theory that has ever been found to be useful. The concept of the photon, however, together with its wave-particle duality, is the simplest that has been advanced which is capable of explaining all the observed phenomena in the very broad field of optics. It's perfectly reasonable to speculate on what would be the effect if our understanding of the nature of light were shown to be erroneous. However, as long as it continues to explain all the phenomena that are relevant, and to predict new uses of optical systems, and as long as you don't have a better alternative, then if it's all the same to you we'll carry on using it.
As for inhibiting future progress, that would be the consequence of rejecting one of the most useful physical theories ever devised, rather than of continuing successfully to test its predictions in ever more complex scenarios.