Posted: Oct 07, 2011 1:54 pm
twistor59 wrote:
I'm not sure if we can say that it has a "physical nature", at least not in general, and not directly, it's a component in a model. Using this component you can construct observables, with which you can make (probabilistic) predictions about measurable quantities.
And those measurable quantities are mass, charge, spin, parity. Never mind that the initial assumption is that we have particles in the model.
This reminds me of Boltzman who postulated that a gas was made of atoms and proceeded to change the whole field of thermodynamics. He never saw atoms, and atoms were only confirmed years after his death. Yet, during his lifetime, he was ridiculed for believing that atoms were real. I guess you would have been one of these people laughing at him.