Whoever has seen Brian Greene has enjoyed his friendliness, charm and intelligence. His personality shines also in his books. But recently, something awful happened: he now talks about the "multiverse".
If the universe is defined as all there is, what can a "multiverse" be? Nothing - it cannot be.
Conversely, a "multiverse" can only exist if one redefines the universe to a concept that does not contain everything. But then it is not a universe!
Following the "multiverse" nonsense, in another universe, there is another Brian Greene saying the opposite of what he is saying in this one. Which of them should we believe?
How can people get away with the "multiverse" nonsense? Are they not married? Don't they have real friends who tell them? One scientist that does not follow reason - that might be a sad story. But dozens, hundreds of such scientists? That is an epidemic!
Scientists only talk about things the can measure - things they can interact with. So maybe the Brian Greene we know is constantly hearing all the voices and opinions of all the other Brian Greenes in the other universes, and he must constantly navigate through this cacophony? Maybe he has heard from another Brian Greene in another universe that the less reason he uses, the more books he sells?
The more mundane explanation might be, however, that the multiple Brian Greenes are his multiple personalities. To contain the epidemic, we need more therapists. But in this universe, please!