The Tufte lecture will be posted on YouTube and iTunesU before the end of the month. In the meantime, you can have a look at the chapter called “The Fundamental Principles of Analytical Design” in his 2006 book, Beautiful Evidence. He published there many of the ideas he presented.

What a great question. I was thinking about similar issues myself when listening to Prof. Tufte speak–how far can we apply some of principles of analytical design to medieval diagrams? And where we can’t, what might be an alternative set of principles we could use to judge “graphical excellence” (to use a Tufte phrase) in the Middle Ages? As you point out, the Sawley Map with its mix of literary, mythical, and actual places and its disregard for geographical accuracy in the modern sense does put Tufte’s standards to the test. In many ways the map does adhere to his principles. For instance, it does offer “multivariate analysis” (principle 3) and an “integration of evidence” (principle 4). I suspect the real difficulty for Tufte might not lie in the map’s design, but in the kind of information it conveys and the premise on which it was created. After all, it does not seek to present information based on empirical evidence. It is not grounded in the physical laws of nature.

But would it be fair to expect or want that in a medieval diagram?

Medieval scientific knowledge and the diagrams used to explain it had an entirely different set of aims from our own and those aims were predicated upon a different set of questions–questions posed by smart people. (Part of why I love studying the Middle Ages is that it allows me to better see the historical particularity of our moment.) Medieval thinkers thought it paramount to explain the cosmos in a comprehensive fashion and present it as a coherent system. As a number of scholars of medieval maps have suggested, the goal of maps such as Sawley was to convey in a glance the totality of both time and space. Sawley very much speaks to the encyclopedic ambitions of medieval scholars and diagram-makers. They were eager to offer a truly all-embracing and integrated view of the world. By that criterion, it seems to me Sawley is eminently successful as a form of visual communication.

If you want to read more about medieval maps, Evelyn Edson has written a marvelous introduction to the topic in her book called Mapping Time and Space: How Medieval Mapmakers Viewed their World.

The consanguinity chart, for example, seems to meet most of his standards and to make its case beautifully. The Sawley Map, on the other hand, is a tougher case, one that I feel certain Tufte would consider a failure, given his admiration for the very modern-looking Chinese map, complete with rectilinear grid, that he displayed in his talk. Does the medieval appreciation for the Sawley map challenge the universality of Tufte’s rules?

Thank you very much for such an outstanding exhibit. It was very nice to have so much information accompanying each piece and furthermore, the information you are adding in this blog (and the links) have extended the delight for several more hours.
I have also been fascinated by the geometry embedded in all these diagrams, maybe by my mathematical background, so hopefully I will be able to attend Prof. Tufte’s talk.

Best regards,