So you’re at a party with friends, and Steve asks what you’ve been reading lately. You launch into a description of Sarah Bakewell’s “How to Live, A Life of Montaigne,” her biography of the “father of the essay,” telling Steve enthusiastically how much you’re learning from this book and how you want to read some of the Frenchman’s essays. Less than two minutes into your narrative, you notice that while he’s nodding at the appropriate places and saying such things as “interesting” or “wow,” Steve is looking past you at the treats the hostess is bringing to the hors d’oeuvres table. You might as well be talking to the sofa. Or, even worse, a friend is telling you about his camping trip with his sons last weekend. He mentions to you the canoe they rented for an afternoon, and that word canoe sends you back to our own childhood when …