In Law and Revolution, law professor Harold Berman famously described how legal pluralism, a central feature of the Western legal tradition, traces back to the Middle Ages. And medieval legal pluralism was not simply a product of competing jurisdictions, but of a philosophy comfortable with complexity generally.
Here is an interesting-looking new book on medieval philosophy from Penguin Random House, The Wisdom of the Middle Ages, by Michael K. Kellogg. The publisher’s description follows: