Comment by codethief

> no one believes that interpretation now

I know of at least one (tenured) person that does, at least to some degree: Felix Fenster at Regensburg University. When I met him years ago, he said taking the Dirac Sea interpretation seriously was what caused him to come up with his own program for a theory of quantum gravity, called Causal Fermion Systems[0]. I haven't looked into his theory in detail but I did find a reference to the Dirac sea[1]:

> In order to obtain a causal fermion system, we first have to choose a Hilbert space. The space of negative-energy solutions of the Dirac equation (i.e. the Dirac sea) turns out to be a good choice. […] As a side remark, it is worth noting that the Dirac sea vacuum is to be seen as an effective model describing a particular minimizing causal fermion system. It is one particular physical system that we can describe as a minimizing causal fermion system. But we should really only think of it as an effective description, in the sense that it describes only the macroscopic structure of spacetime, whereas its microscopic structure on the Planck scale is essentially unknown. […] The idea of the Dirac Sea did, however, play an important role in the conception of the causal fermion systems framework, and most of the existing literature is written with that point of view in mind. A more detailed motivation for why it is a natural starting point can be found here[2].

[0]: https://causal-fermion-system.com/

[1]: https://causal-fermion-system.com/intro-phys/

[2]: https://causal-fermion-system.com/theory/physics/why-dirac-s...