In chapter 10 of Robert D. Klauber's excellent QFT book, there's a nice overview of different concepts occurring in the context of vacuum fluctuations. Inspired by that chapter I ask: If one would state that there is no such thing as vacuum fluctuations, what counter arguments are there? In particular, QFT doesn't seem to provide a mechanism for spontaneous pair production in the vacuum. The "vacuum bubble" term of the Dyson-Wick expansion in QED only describes virtual, not real, particles, does not have any measurable effects or interactions with the physical world, and is no reason to believe that anything physical is created in the vacuum. Also, the energy-time uncertainty relation *allows* for vacuum fluctuations but does not say that those occur. Is there *any* reason to believe that particles are created and destroyed spontaneously in the vacuum other than that many physicists *believe* this is the case?