Like every graduate student, I once holed up in the library cramming for my doctoral oral exams. This ritual hazing starts with a long reading list. Come exam day, the scholar must prove mastery of a field, whether it’s Islamic art or German history. The student sits before a panel of professors, answering questions drawn from the book list.
To prepare for this initiation, I bought a lifetime supply of index cards. On each four-by-six rectangle, I distilled the major points of a book. My index cards—portable, visual, tactile, easily rearranged and reshuffled—got me through the exam.
Yet it never occurred to me, as I rehearsed my talking points more than a decade ago, that my index cards belonged to the very European history I was studying. The index card was a product of the Enlightenment, conceived by one of its towering figures: Carl Linnaeus, the Swedish botanist, physician, and the father of modern taxonomy. But like all information systems, the index card had unexpected political implications, too: It helped set the stage for categorizing people, and for the prejudice and violence that comes along with such classification.
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In 1767, near the end of his career, Linnaeus began to use “little paper slips of a standard size” to record information about plants and animals. According to the historians Isabelle Charmantier and Staffan Müller-Wille, these paper slips offered “an expedient solution to an information-overload crisis” for the Swedish scientist. More than 1,000 of them, measuring five by three inches, are housed at London’s Linnean Society. Each contains notes about plants and material culled from books and other publications. While flimsier than heavy stock and cut by hand, they’re virtually indistinguishable from modern index cards.