Susskind 2025: Nobody Understands Quantum Mechanics: Crisis

Leading theoretical physicist Leonard Susskind at the end of his career apparently feels an urge to confess some truths about the present state of modern physics (in a state of deep crisis):

• We know how to use Standard Quantum Mechanics StdQM.
• But the basic meaning of StdQM is not understood at all.
• Feynman said: StdQM is so confusing that I cannot even tell if there is a problem about the foundations of StdQM.
• Everybody I know will tell you that the ultimate meaning of the foundations of StdQM is not understood.
• There are always crazy theories like Many-Worlds that does not make a lot of sense to me.
• I really think that we don't understand StdQM at the deepest level.
• I think the problem is that when we think about a quantum mechanical experiment we separate the world into the system we are studying ... and the apparatus of the observer... the apparatus is not part of the system.
• That is why we have the problem of the collapse of the wave function...there is no collapse.
• I do not know what is right, so I cannot say what is wrong, e g super-determinism....  

We hear Susskind repeat the message of all great theoretical physicists of modern physics: 

• We do not understand StdQM. 
• But we know very well how to use it!

This would be like hearing a famous mathematician saying: We do not understand Calculus, but we know very well how to use it. This could be the confession of a high-school student, but not by his teacher and certainly not by a professional mathematician. 

Likewise, to hear a professor of the theory of electro-magnetics described by Maxwell's equation say that the theory is not understood by anybody but anyway has shown to work very well, would be surprising. Only about StdQM is it a virtue to signal no understanding. 

How is it possible that still today exactly 100 years after the birth of the foundation of StdQM in the form of Schrödinger's Equation SE, that very foundation is still not understood not even by leading theoretical physicists? 

There is an answer of this form: 

• SE is a linear equation in $3N$ space dimensions for a system with $N$ electrons, and as such has no direct meaning as physics in 3 space dimensions. 
• SE is an ad hoc purely formal generalisation from one electron to many electrons without physical meaning.
• Since SE has no physical meaning, QM has no physical meaning to be understood.
• SE can be used as a black box to produce numbers, but with unclear or no physical meaning.   

There is an alternative to StdQM in the form of Real Quantum Mechanics QM, which has physical meaning and so can be understood. Why not check it out?

Question connecting to recent post: 

• Can StdQM help to make the Periodic Table understood, if StdQM cannot be understood?

Comment by chatGPT:

• Quantum mechanics is unique in that its very foundation is admitted to be incomprehensible — even by its leading experts. No other science could survive with such a gap at its core, and this is a prime reason for the present crisis of physics.