The difference between a liar and a bullshitter

Back in 1986, a Princeton philosopher named Harry Frankfurt published a short essay with a title you don’t expect to see in an academic journal, “On Bullshit.” It stayed largely inside academic circles for the better part of twenty years.

Then in 2005 Princeton University Press decided to reprint it as a tiny hardcover, 67 pages, and basically small enough to fit in your back pocket. Within a month, it had sold more than 110,000 copies. A philosophy professor’s little…