I don't understand why you insist that a number that has a large uncertainty cannot be meaningfully specified, when you yourself demonstrate putting constraints

I don't understand why you insist that a number that has a large uncertainty cannot be meaningfully specified, when you yourself demonstrate putting constraints on it. That is giving it a meaning. There are about 49 Gutenberg bibles known to remain of 158-180 copies, I read. log2(49/169) = -1.8; 570/1.8 = 316 years for half of them to disappear. It's very meaningful to say that a number is between 10 and 1000. It's not 10,000; it's not 100,000, or 1,000,000. There are maybe 10^82 atoms in the universe. That's about 2^272 so saying I am confident the half life of even the best preserved, most cherished books is less than 1000 years means that a 300,000 year old book could not exist. Because even if there were 10^82 of them, not one would be left. If you really insist you cannot quantify it, you're saying there's a chance! Aren't you? With DNA, it's not that I know the half life is 1375 years precisely, or have hardly any biological knowledge, but the little knowledge I have combined with exponential rates of loss constrains it so I can't imagine the upper bound is above 10,000 years. The thing I am trying to express is that even huge uncertainty and almost total ignorance give you far more to work with than "nothing".