The philosophical novel is alive and well as a literary form, and a venue of philosophizing. I think of John Updike, ROGER’S VERSION (1986), Rebecca Goldstein, THE MIND-BODY PROBLEM (1993), David Foster Wallace, INFINITE JEST (1996), E.L. Doctorow, ANDREW'S BRAIN (2014), and John Irving, AVENUE OF MYSTERIES (2015). But let us go back to Wallace. I included INFINITE JEST in my little list above because it is explicitly philosophical, built as it is around the challenging notion that "the truth shall set you free. But not until it is finished with you." Confronting reality may indeed set us free from the impediments of our preferred delusions. But it is painful to let them go. Separately, an earlier book of Wallace's, THE BROOM OF THE SYSTEM, make an intriguing use of Ludwig Wittgenstein, a use that justifies the title. BROOM starts with the news that an elderly woman is missing from her retirement home. The missing person was once, in her youth, a stud...