The distinction is that a theory of "unicorns" is a theory that describes how and why other people (and probably you yourself) think about unicorns, while a theory of unicorns would explain actual unicorns. The latter would clearly fail as a theory, because you're never going to actually see a unicorn.
The same distinction doesn't apply to Newtonian mechanics, because Newtonian mechanics is a theory of mechanics, not a theory of how people think about mechanics.
On those grounds, I think it's quite reasonable to say that virtual particles are real, and "unicorns" are real, but unicorns are not real.
The same distinction doesn't apply to Newtonian mechanics, because Newtonian mechanics is a theory of mechanics, not a theory of how people think about mechanics.
On those grounds, I think it's quite reasonable to say that virtual particles are real, and "unicorns" are real, but unicorns are not real.
Not sure if you read anything I wrote in this thread. Note that both Newton's laws and "unicorn" laws are models. You don't find Newton's laws in Nature, just like you don't find "unicorn" laws. You don't find virtual particles,...
What is something you used to believe, preferably something concrete with direct or implied predictions, that you now know was dead wrong. Was your belief rational given what you knew and could know back then, or was it irrational, and why?
Edit: I feel like some of these are getting a bit glib and political. Please try to explain what false assumptions or biases were underlying your beliefs - be introspective - this is LW after all.