Multiverse

I already owed Sean Carroll a proper post. When I wrote A New Universe All Throughout The Day I admitted, almost in passing, that he was the person who really led me into taking the many-worlds interpretation seriously rather than treating it as a science-fiction gimmick. Then two New Scientist videos landed in front of me within a few weeks of each other - one titled We May Never Understand Reality and one titled Why Quantum Physics Says There’s a Multiverse - and I realised I had been circling him for months without ever writing the man down. This is me doing that. ...

I have written about one of Max Tegmark’s ideas already - the Mathematical Universe Hypothesis - and in doing so I admitted he sits at the top of my favourite physicists list. That post was about a single claim. This one is about the man, and about the thing I find more interesting than any individual theory of his: the through-line. Tegmark has spent a career moving steadily inward, from measurable cosmology toward the deepest possible questions about what reality is, and the move never feels like a physicist losing the plot and drifting into metaphysics. It feels like someone following the maths until it runs out of floor. ...