Ethan, this is another great article. You are 50% of the reason I stick with Medium, I hope they are paying you enough! :-)

Can you, or another knowledgeable reader help me understand the epistemological status of "virtual particles"

There are many particles whose existence are known to us via indirect means, yet we do not call them "virtual" they are "real" but are just too tiny to see.

Indeed physicists used to view quarks as 'virtual' or as an 'accounting trick' for a period of time before we decided they were in fact "real". I just wonder why we continue to refer to a certain class of photons a "virtual" when they are needed to make our predictions match.

Is there something missing that makes us think they might not really be there, and are instead simply an accounting trick?