Well, you're all going just a little bit too far. Sorry. You're characterizing the Zone System through the unfortunately poor re-writes, bastardizations, "additions" and "improvements" to Adams made over the years by people who want to sell books. I would also point out Adams seems to have been as aware of, and interested in subjective considerations as Stephen. Mees appears to have endorsed the Zone System as it originally existed. Finally, a careful reader of Adams will note he does not claim any of the transmission/reflection densities, Zones etc are absolutes. It is just an introduction to applied sensitometry, and all introductions and simplifications are 'crude'. They have to be, because most people are crude and have no interest in detailed learning.