Interesting bit of trivia: the S-matrix concept is also where the so-called S-parameters came from, which are used by RF engineers to describe amplitude and phase relationships at input and output ports [1].

There was some cross-pollination with the physics community in the 1960s that helped the RF people with circuit modeling problems they were facing due to the limitations of existing models. [2] Hewlett-Packard jumped on this with both feet [3], because S-parameters were a natural fit not only for modeling linear devices and circuits, but for measuring them using the vector network analyzers they were developing at the time.

[1] https://cds.cern.ch/record/1415639/files/p67.pdf

[2] https://typeset.io/papers/power-waves-and-the-scattering-mat...

[3] http://www.hparchive.com/Application_Notes/HP-AN-95-1.pdf

Nice exposition on the physics side; the S-matrix formalism has also played a major role in the mathematical theory of quantum chaos and aspects of representation theory.

Maybe we don’t need a new model, but rather just accepting that the universe can be two seemingly opposite things at the same time

Like the particle/wave duality

Maybe the whole universe is both quantum and not, at the same time. And we just perceive it differently at different scales. Like with a stroboscopic light, we might perceive things differently depending on how we are sampling (and not necessarily because the thing is different)