The List That Ran for Four Centuries

Institutional control of reading is usually discussed as though it were a tendency: subtle, deniable, visible only in aggregate. For four centuries in Europe it was none of those things. It was a printed list with an author, a publisher and edition numbers.

The Index Librorum Prohibitorum was first issued under Pope Paul IV in 1559 and maintained through thirty-two editions. The final edition appeared in 1948. It was formally abolished in June 1966, which is recent enough that people who read the last edition as a live document are still alive.

The contents are not what a modern reader expects. The Index was not primarily aimed at obscure occult material. It listed Copernicus, whose On the Revolutions was suspended in 1616 pending correction. It listed Galileo, Kepler and Descartes. It listed Montaigne, Locke, Hume, Voltaire, Rousseau and Kant. It listed Pascal, whose offence was a dispute internal to the church. In the twentieth century it added Sartre and Simone de Beauvoir. The great majority of listed authors were not heretics in any theological sense. They were people whose method produced conclusions the institution could not accommodate.

The mechanism is worth understanding precisely, because it was not a bonfire. Prohibition operated through the ordinary infrastructure of publishing. Printers required licences. Booksellers were inspected. Importation was controlled at ports. A listed book was not usually seized and burned; it simply became commercially unavailable in Catholic jurisdictions, which for most of this period meant unavailable in most of Europe.

That distinction matters because it is the form suppression usually takes and the form it is hardest to notice. Nothing dramatic happens. A book is not destroyed. It is merely never printed, never stocked, never taught, and after two generations it is not that the book is forbidden but that nobody has heard of it.

The Index also had a companion instrument that gets less attention. Expurgation permitted a book to circulate once specified passages were removed. Copernicus was restored on those terms: ten sentences altered, the heliocentric model reduced from a description of reality to a computational convenience. The book remained in print. The claim in it did not.

There is a common and lazy reading of this history in which the church is simply hostile to knowledge, and it does not survive contact with the record. The same institution ran the universities, preserved the classical corpus through the early medieval period, and employed most of the scientists it later censured. The picture is not hostility. It is an institution with a monopoly on legitimation deciding, case by case, what it could afford to have said.

The abolition in 1966 was also not a repudiation. The accompanying notification stated that the Index retained its moral force as guidance while ceasing to carry the force of church law. What ended was the mechanism, not the position.

Four hundred and seven years of continuous operation, thirty-two editions, and the names of the people who compiled each one. This is the least deniable episode in the whole history of suppressed knowledge, and it is the one least often cited by people who are certain knowledge has been suppressed.

The uncomfortable question is not whether it happened. It is which of our own unavailabilities are the result of a decision that was documented at the time and has simply stopped being read.