“Physicists do not like the word ‘reality’. We may talk about it all the time but when it comes down to it, we really don’t want to say this is reality and that’s not reality. There are mathematical connections between things and that’s got to be it, because we don’t have enough insight to tell what is reality.
Our neural wiring that we inherited was not built for quantum mechanics or higher dimensions, it was not built for thinking about curved space time. It was built for classical physics, for rocks and stones and all the ordinary objects and three dimensional space. That’s not quite good enough for us to be able to visualise and internalise the ideas of quantum mechanics and general relativity and so forth. So instead, we Physicists use mathematics. Eventually, in time, we develop intuitions out of abstract mathematics, we get better at it. We begin to think that way. But it can be extremely frustrating when trying to explain that to the outside world.The outside world by and large has not had that experience of going through the rewiring process of converting their minds into something that can deal with five dimensions, ten dimensions, uncertainty principal or whatever happens to be. So the best we can do is to use analogies or metaphors. And the holographic principle is a metaphor.
I think there is only one thing that’s certain, that there will be surprises. Some of them will come from experiments, some of them will come from giant telescopes, and some of them will come from mathematical and theoretical thinking about how things fit together. One can be pretty sure that anybody who says that they have the final answer now, is smoking something bad.”
– Leonard Susskind, one of the first proponents of the Holographic Principle and the first to present a precise String-theory interpretation of the same, in his interview Is The Universe A Hologram?