I think the 2nd law of thermodynamics, which places limits on the efficiency of thermal engines, can also be interpreted as saying increasing efforts to improve efficiency result in geometrically decreasing results. I can't find that stated, though. I suppose it's just the first derivative of something, but I'm real rusty on that and don't see quite how to do it. Is that worked out somewhere? What I'm also looking for is any discussion on the broader principle, consistent with the above, that in exploiting any opportunity it's inevitable that you do the easy parts first and if you want to get more out of the 'same' thing, all that's available are the harder parts. Like in polishing a mirror. Going from 100 grit to 1000 grit to 10000 grit is the way to get a nice shine but each step is lots more work, to move less and less material, and the task approaches a natural point of phsical refusal, unattainable perfection. I've been thinging about it as one of the rare general cases where Zeno's paradoxes actually do apply, and wondering how to tell all the good folks who are talking about removing growth limits with it the bad news... Anyone know of a discussion on any part of this?