Abstract

We point out some concepts that appear rather frequently in physics discussions, which, despite a seemingly innocent initial appearance, turn out to have important implicit implications that put into question the very assumption of their meaningfulness. The message of this essay is that, in order to avoid the ensuing confusions, their usage should be accompanied with clarifications that make them meaningful, and then to confront the often uncomfortable underlying assumptions required to do so. In particular, we will visit the notions of novel physics occurring at a certain energy scale, or at certain distance from a black hole’s event horizon, and the various meanings of the word “fluctuations”.