UPDATE: Sean Carroll (previously) has a well-argued critique of Cox’s explanation. Thanks, Siddharth.

Last week, physicist Brian Cox showed us why everything that could happen does happen in a riveting tour of the quantum universe. In this fascinating short excerpt from BBC’s A Night With The Stars, Cox turns to the Pauli exclusion principle — a quantum mechanics theorem holding that no two identical particles may occupy the same quantum state simultaneously — to explain why everything is connected to everything else, an idea at once utterly mind-bending and utterly intuitive, found everywhere from the most ancient Buddhist scripts to the most cutting-edge research in biology and social science.

This shift of the configuration of the electrons inside the diamond has consequences, because the sum total of all the electrons of the universe must respect Pauli. Therefore, every electron around every atom in the universe must be shifting as I heat the diamond up, to make sure that none of them end up in the same energy level. When I heat this diamond up, all the electrons in the universe instantly but imperceptibly change their energy levels. So everything is connected to everything else.”

For a deeper dive into this infinitely fascinating world, treat your mind to Cox’s The Quantum Universe.