That excellent writeup reinforced something I've become convinced of: decades of "shut up and calculate" have created gobs of contradictory analogies and false intuitions that pedagogy hasn't caught up to. When I hear:
"In the jargon of field theory, physicists often say that “virtual particles” can briefly and spontaneously appear from the vacuum and then disappear again, even when no one has put enough energy into the field to create a real particle. But what they really mean is that the vacuum itself has random and indelible fluctuations, and sometimes their influence can be felt by the way they kick around real particles."
I can't help but immediately question every jargon word I see, especially "random", "particle" and "wave".
Metaphors have limited applicability. The applicability of metaphors in quantum field theory that the public is ever exposed to is pretty mich limited to sounding cool and inspiring some awe in the face of all the mistery and complexity.
Im my experience, all terms in physics (like "particle", "wave", "energy") are highly context dependent and most PhDs could spend hours debating what is actually meant in a given case. Such discussions almost never lead to publishable results and are thus considered a waste of time, or leasure at best.
Usually, you just "shut up and calculate". Meanwhile, the calculations are motivated by "intuition", which involves combining known or unknown reasonable approximations with a basic theory. This process is never explained systematically and rather the hope is that it will be absorbed via osmosis by the brighter students.
It turns out, you actually don't need to have a coherent concept of "what a particle is" to perform particle physics experiments and evaluate the data. Sometimes, when pressed, operational definitions can be offered. For example, I've heard a professor say: "a particle is defined as a bump at a given energy in this plot". I'm not sure how ironic that was supposed to sound...
In a certain sense I've become pessimistic about the possibility of ever assigning a meaningful ontology to objects at that scale. We have models which give results. Some ways of calculating scattering amplitudes make reference to virtual particles at all. I've begun to think that there is no way to understand physics _except_ to become acquainted with the mathematics of it. The analogies are pointless.
"In the jargon of field theory, physicists often say that “virtual particles” can briefly and spontaneously appear from the vacuum and then disappear again, even when no one has put enough energy into the field to create a real particle. But what they really mean is that the vacuum itself has random and indelible fluctuations, and sometimes their influence can be felt by the way they kick around real particles."
I can't help but immediately question every jargon word I see, especially "random", "particle" and "wave".