I'm trying to point to the set of all jobs a human being could do, which includes future jobs enabled by future technology.
This is not as nebulous of a set as it sounds because it has real human boundaries: there are limits to how fast we can learn, think, communicate, move, etc. and there are limits to how consistently we can perform because of fatigue, boredom, distraction, biological needs like food or sleep, etc. The future is uncertain, but I don't see why an AI system couldn't push past these boundaries.
Maybe if AI could do all jobs humans could do, we'd setup some system where the AI works and we don't since we tax them or somehow at least part of the created goods and services flows to everyone. Anything AI "creates" is worthless unless it's consumed, and AI being a machine/software won't inherently want to consume anything (like burgers for example).
I also struggle to think about all this, but I imagine if you can flip a switch and everything produced and consumed in the economy could be done in half the time, is that a good or bad thing? If we keep flipping that switch and approaching a point where everything is being produced with almost no human effort, does it become bad all of a sudden?
Somehow we'd need to distribute all this production, I'm not sure how it would work out, but just going from what we have now to half or 25% of effort needed is probably an improvement, at least I'd take that.
This is not as nebulous of a set as it sounds because it has real human boundaries: there are limits to how fast we can learn, think, communicate, move, etc. and there are limits to how consistently we can perform because of fatigue, boredom, distraction, biological needs like food or sleep, etc. The future is uncertain, but I don't see why an AI system couldn't push past these boundaries.