Aug 5, 2026 08:50 PM
(This post was last modified: Aug 5, 2026 08:52 PM by C C.)
PAPER: https://journals.aps.org/pra/abstract/10.1103/kmmy-3dy3
SABINE HOSSENFELDER
https://youtu.be/SMXq68UeeXU
VIDEO INTRO: For a decade or so, I've complained that physicists seem content with quantum mechanics as it is. They don't try to fix its problems. Rather, they tell themselves and everyone dumb enough to believe it that we must accept the quantum weirdness. By now, they've glorified the strangeness of quantum mechanics so much, it's become basically impossible for them to move beyond it. If something makes no sense, don't fix it. Give it a mysterious name and start a pop cast.
And yet today, I have a team of physicists who've done exactly that. They've looked for the origin of quantum physics and found at least a possible one. That's intriguing because physicists said it's impossible. Let's have a look.
One of the biggest mysteries on the foundations of physics is one you might never have thought about, causality. We're so used to it, we never even think about it. Flip a switch and the light goes on. Cause and effect, simple enough, unless you have children, in which case the effect just happens and the cause denies involvement. But where does causal order come from? Why is the world so neat and orderly? The authors of the new paper say, "Actually, it isn't. Causality doesn't fundamentally exist any more than say a liquid does. A liquid is fundamentally made of particles. Yet the particles themselves aren't liquid. That just doesn't make any sense. The liquidness is an emergent behavior for a large collection of particles."
The authors of the new paper say causality is like that. It doesn't exist on the fundamental level. It's an emergent behavior that we observe for many quantum particles. The reason I find this interesting is not just that it could explain the origin of causality. It's also that causality is one of the reasons why it's so difficult to combine quantum physics with gravity. Physicists have been looking for such a combination, a theory of quantum gravity, for almost a century...
https://youtu.be/SMXq68UeeXU
https://www.youtube-nocookie.com/embed/SMXq68UeeXU
SABINE HOSSENFELDER
https://youtu.be/SMXq68UeeXU
VIDEO INTRO: For a decade or so, I've complained that physicists seem content with quantum mechanics as it is. They don't try to fix its problems. Rather, they tell themselves and everyone dumb enough to believe it that we must accept the quantum weirdness. By now, they've glorified the strangeness of quantum mechanics so much, it's become basically impossible for them to move beyond it. If something makes no sense, don't fix it. Give it a mysterious name and start a pop cast.
And yet today, I have a team of physicists who've done exactly that. They've looked for the origin of quantum physics and found at least a possible one. That's intriguing because physicists said it's impossible. Let's have a look.
One of the biggest mysteries on the foundations of physics is one you might never have thought about, causality. We're so used to it, we never even think about it. Flip a switch and the light goes on. Cause and effect, simple enough, unless you have children, in which case the effect just happens and the cause denies involvement. But where does causal order come from? Why is the world so neat and orderly? The authors of the new paper say, "Actually, it isn't. Causality doesn't fundamentally exist any more than say a liquid does. A liquid is fundamentally made of particles. Yet the particles themselves aren't liquid. That just doesn't make any sense. The liquidness is an emergent behavior for a large collection of particles."
The authors of the new paper say causality is like that. It doesn't exist on the fundamental level. It's an emergent behavior that we observe for many quantum particles. The reason I find this interesting is not just that it could explain the origin of causality. It's also that causality is one of the reasons why it's so difficult to combine quantum physics with gravity. Physicists have been looking for such a combination, a theory of quantum gravity, for almost a century...
https://youtu.be/SMXq68UeeXU
