My latest creative taxonomic classification concerns the literary grouping we will call flight books – books that cause transatlantic flights to evaporate. Flight books do not need to dazzle or send us dreaming, though they often do. They do not need to be fiction, though they frequently are. Volumes of poetry make poor flight books, and anything from the pile of Books You Really Need To Read For A Reason Other Than Sheer Pleasure belong to another species. Large or heavy books should be checked, along with machetes, hedge clippers and other inappropriate in-flight articles.

You want a book that carries you away without overly taxing your brain synapses, for at every pause in the narrative you risk remembering where you are, what you’re running from or traveling to, and how many hours until your life returns. ‘Tis better to travel than arrive, unless you’re wedged in economy class.

This book is neither fiction nor dazzling, but it is altogether satisfying and fits the bill as a perfect in-flight reading. Plato has a joke to tell – too many jokes, perhaps, but they pass quickly. Reading it is like meeting a smart stranger at a bar and falling into an unexpectedly deep confabulation. When the bar closes or the journey is over, you can take with you as little or as much as you please.

The triumph of empiricism in Western epistemology is reflected in the fact that we automatically assume it to be the method of verification that everyone uses:

Three women are in a locker room dressing to play racquetball when a man runs through wearing nothing but a bag over his head. The first woman looks at his wiener and says, “Well, it’s not my husband.” The second woman says, “No, it isn’t.” The third says, “He’s not even a member of this club.”

Still, despite the triumph of empiricism and science, many people continue to interpret some unusual events as miraculous rather than the result of natural causes. David Hume, the skeptical British empiricist, said that the only rational basis for believing that something is a miracle is that all the alternative explanations are even more improbable. Say a man insists he has a potted palm that sings arias from Aida. Which is more improbable: that the potted palm has violated the laws of nature, or that the man is crazy, or fibbing or high on mushrooms? Hume’s response: “Puhleez!” (We’re paraphrasing here.) Since the odds of the man having been deceived are always somewhat greater than the odds of a violation of the laws of nature, Hume could foresee no circumstance in which it would be rational to conclude that a miracle had happened.