16th century lessons on fake news and disinformation

I’ve just been reading an interesting book on the relationship between two 16th-century social-media influencers, Desiderius Erasmus and Martin Luther (Fatal Discord, by Michael Massing). I was struck by one comment that came up at the Diet of Worms that speaks to our current conundra over propaganda and disinformation.

Luther argued that he could not recant all of his writings, since some stated truths universally acknowledged by Christians. They must point out to him which particular assertions were false, and demonstrate the falsity with citations from genuine authorities, which could only be scriptural.

Determined not to be drawn into a debate, the theologian Johann Eck countered that Luther’s

assertion that some of his books contained teachings that were sound and acceptable to all was specious, for heretical books, going back to the Arians, had been burned, despite containing much that was godly and Catholic. In fact, Eck said, no doctrine is more effective in deceiving than that which mixes a few false teachings with many that are true.

This is a clear formulation of the principle of optimal fakery that I have discussed at length in this essay.