Taken from the January 2020 issue of Physics World.
In physics, asking the question “Is it real?” is a slippery slope, and the answer often depends on the level at which something is modelled. In this article (originally published in Lateral Thoughts, Physics World’s regular column of humorous and offbeat essays, puzzles, crosswords, quizzes and comics, which appears on the back page of the print edition) Michael Berry explores the depths of our perceptions