While I was teaching a decade ago at a large university, one year’s annual faculty in-service focused on using technology in the classroom. This essentially boiled down to getting all the teachers to use Powerpoint. “Students these days are visual,” the argument went, “and they struggle to learn unless you also have a presentation.” Predictably, the following semester saw a burgeoning of painfully formatted Powerpoints and no particular increase in educational success. Teaching, preaching and presenting are now the main thing I do with my life. And I’ve developed a minor allergy towards...