steve voigt
Ha, pointless is right. I know you are responding to Dave, who has a different point of view, but just to be clear, I never said the knowledge was lost. I gave a specific example of someone who credibly had learned it long ago (Richard Maguire), I wrote that "of course there were craftsmen…who knew about the double iron" and "it's incorrect to argue that the knowledge was ever truly lost." Then someone else tried to twist that into a bogus straw man argument, because straw man arguments are always easier to refute.

David and I might disagree about, as you say, whether it's 90% or 95% or whatever, which is not all that important. But we agree on the main point, which I'll convey with an analogy: If you add up all the people who say they were there at Woodstock in 1969, you could probably populate a decent sized country. If someone says they were there, maybe it's true, but forgive me if I'm skeptical until they show me a ticket.