Physicists are always proposing mind-bending approaches to describe the universe, especially to reign in the edge cases of mathematical models. There was a theory the world was all just a hologram, relying on an encoding of information allowing multi-dimensions to seem to exist even if they did not.

Of course, I'm probably butchering this because nobody but the most hardcore physicists actually understand string theory and its tenets. But it doesn't matter anymore because at the Department of Energy's Fermilab, physicists spent $2.5M to prove we DO NOT live in a hologram. They used a holometer, which was a pair of laser interferometers shooting beams through a splitter down a distance after which they are recombined. The device essentially allows scientists to determine whether there are fluctuations in space-time. What did the holometer prove? Well, a particular quantum jitter that should exist if we are in a hologram was not present so the world as we know it ... is status quo.