>>13359403well, think about how his approach can be used to draw other conclusions. If his method bears no fruit elsewhere, then it is unlikely to be doing anything where he used it. His description is centered around the use of the self-concept, 'I,' and connecting many other things from there.
Want to know a cool thesis that can be considered isomorphic to this? Memes.
Extending this, perhaps a bit too far, alphabets icons and phonemes also qualify. They wouldn't be very easy to study, suffering from the same but even more exaggerated problem as Jaynes' thesis. Memes are well-documented, easily accessible although not cataloged, and originate in well documented and cataloged places. When I say memes, I don't mean just any vector for spreading an idea. I mean specifically the stupid or funny, cringy or snarky, sharables.
The more I think about it, if it can be applied to memes, photography and the printing press should also have fundamentally changed consciousness as well. So there are plenty of areas where the hypothesis can be generalized to and tested. What kind of work has been done on studying the changes in printed books to those that were scribed? I imagine there must be a lot of studies on that.