I understand that as an honest statement/question. He was always still searching for stuff, when I was the last student & done with a lesson sometimes it was his turn to practice, he had been himself been re-obsessing with possibilities in second position during my time with him. So it's just that, there isn't a way he's found to play four notes and make the other musicians understand a specific entire mode right away.
Unlike playing four notes and giving someone an idea of what chord you're dealing with. If you play C A E G, well you could propose some other possibilities... A-7 is the obvious one, especially with context, but if you start with that, those 4 notes communicate a pretty likely C6.
C E G Bb would be quite clearly C7. Abmaj9#5? Possible, but you're probably going to hear C7 right away if the bassist starts with that. We're trying to get everyone on the same page right? So the bassist has this power to play the right 4 notes and communicate a sound of a chord to other musicians.
Since we're communicating with others, it's about getting the other musicians to understand what you want to say. He approaches music in a scientific way, and ears and communication this way too, so I understand it as him trying to find a way to communicate something fast and musically with those 4 notes that he has yet to find.
I don't feel like I really said anything other than what he already wrote haha... but I don't know if that clarifies at all?