jlw
Rangefinder camera pedant
I've seen a bewildering variety of figures from your own 6 megapixels
Six megapixels wasn't "my" figure; it was a figure I calculated, using a certain set of assumptions, and I showed my work in my post so people could make up their own minds whether or not it was legitimate. I didn't just pull out a figure and say "experts agree that X is the magic number."
If you don't want to believe the 18-22 megapixel figure, don't.
It's not a question of me believing it or not believing it. As a matter of fact, if you go back and re-read my post, you'll note that my number-twiddling confirmed your figure, if we assume the eye can distinguish 300 points per inch at normal reading distance (the "laser printer" criterion) and that we're looking at our 35mm slide at 20x magnification.
You hadn't spelled out those assumptions, so I had to go back and derive them. The only reason I was doing this was that I wanted to understand where the 18-megapixel figure might have come from, rather than simply accepting it by fiat. So climb down, nobody's biting you in the gizzard.
Second, as you say, resolution of the human eye as 1 second of arc is at least as defensible as your figure...
Not my figure, Kingslake's -- which is why I included a citation. But hey, who cares what dumb ol' Kingslake thought?