Manuscripts as Fossils: Population-Biology Equations Estimate Medieval Texts' Likelihood of Survival
Klarreich, Erica, Science News
Through the ages, innumerable texts have been consumed by fire, war, theft, and other disasters. Each ancient or medieval manuscript in existence today has its own story of survival against the odds, whether the document was tucked away in an obscure monastery for a millennium or stolen by Vikings and passed from collector to collector. Manuscript experts have long puzzled over the question, what fraction of ancient works has survived?
Paleontologist John Cisne of Cornell University brings a fresh approach to this problem. He regards handwritten medieval manuscripts as fossils from an extinct population. Using equations from population biology, he has created a mathematical model that suggests, happily, that we have at least fragments of the majority of popular medieval titles.
"It looks as if we've got a representative sample of the books in circulation 1,000 or 1,200 years ago, not just a few rare flukes," Cisne says.
Until the invention of the printing press in the 15th century, reproduction of manuscripts had a lot in common with replication of organisms, Cisne argues. Each new manuscript had to be transcribed from an existing "parent" copy, so the more copies in circulation, the more new ones that could be produced. Cisne hypothesized that the number of copies of a given text should grow according to population biology's logistic model: The population would at first increase exponentially, as cliche rabbits do, then gradually level out as it approached the maximum number of organisms that the environment could sustain. For manuscripts, that would be the number of libraries and individuals who wanted a copy.
To test this model, Cisne examined four scientific texts by the Venerable Bede, an 8th-century scholar who is one of the most thoroughly cataloged of medieval authors. By looking at how many copies of his works survive today and in which century, from the 8th to the 15th, each was produced, Cisne found that these texts do indeed fit the logistic model. He describes his work in the Feb. 25 Science.
NUMBERS GAME With his model, Cisne estimates that the likelihood that a popular medieval text would have gone extinct between its creation and the present day is less than 7 percent. This estimate fits well with the availability of the Bede's other works. Of his 35 known books, 32 have survived in some form.
"The numbers are in the right ballpark," Cisne says.
"It's very exciting work," says Florence Eliza Glaze, a historian of medieval medicine at Coastal Carolina University in Conway, S.C. "Classical scholars tend to work with anecdotal evidence, and most of us don't do statistical analyses. …