Thanks to Marden Seavey for posting this item from YouTube, Is light a wave or a particle?
Let me be clear, I am in full support of what Sabine Hossenfelder says in this video. My comments below are only intended to amplify what she is saying. These comments are only intended as an additional way to look at the problem of thinking that there is a paradox here, and seeing how physicists are now avoiding creating such paradoxes in the minds of future students and non-physicists.
It seems to me that physicists started naming things like quarks and leptons to get away from the mistaken idea that likening these quantum mechanics thingies to Newtonian mechanics thingies would provide insight into what they were. That original comparison to familiar concepts left us with the non-answerable question of whether light is a wave or a particle. As Bill Belichick would say, “It is what it is.” As this narrator says, light displays some particle like properties and it displays some wave like properties, but it isn’t either of those two things. Particles and waves are abstract and simplified concepts that describe some properties of certain thingies. These thingies are what they are. You can only talk about the properties that they exhibit.
Put another way, particles and waves are models of reality. They simplify reality so we can write down and solve equations to predict what will happen in reality. Since the concept of particle or wave is a simplification of reality, we can not expect reality to behave only as the simplified model does. Reality is more complex than the model. If it weren’t, we wouldn’t need to simplify it to get some understanding. A simplified model only works in the situations where it is applicable. In other situations the model does not give you correct results at all. In the situation where light can be modeled as a wave, then the wave model is a good explanation of what light does. In situations where light acts as a particle, then the particle model gives a good description of what light does. Outside the domain of applicability, the model does not give a correct description of what light does. If we find a domain in which neither model is good, then we won’t be able to predict what light will do at all. In such a domain, we would have to see what light does, and then try to come up with an explanation of what rules light is following in that circumstance. Rather than calling that third model by a name of something that we have some insight into, we might just give it a wacky name to make sure nobody thinks that light is actually that other thing to which its behavior is similar.
I leave it to my friends who are more expert in physics than I am to tell me where I went astray and said something above that was full of crap.