In the ever-so-slightly meatier portion of the book, Metcalf also offers that the word resonates because it embodies, or gives concise voice to, two American philosophies: the philosophy of pragmatism, which does not "imply or demand perfection" but values, simply, whatever works; and the related philosophy of tolerance and acceptance, best captured by the phrase I'm OK, You're OK (after Thomas Harris' best-selling 1967 pop-psychology classic). Metcalf gives less weight to the relativist OK, or the "noncommittal" OK, as he calls it, which "affirms without evaluating." The word's passivity, to Metcalf, is merely one of its many aspects, rather than an encapsulation of a third, less glamorous American philosophy: the shrug. As American as pragmatism, the shrug, and its verbal counterpart, the noncommittal OK, are everyday necessities for those too jaded or timid to fully embrace, or fully reject, a concept, plan, or work of art. To say that something is "good" or "bad" is to leave oneself open to criticism, but to say that it is "OK" is to play both sides—yeah, the acting was terrible. I didn't say it was "good," did I?
Throughout, Metcalf stresses OK's clarity over its opacity. He does not linger on its potential for unintentionally confusing exchanges (like the one with my friend above) or even willful inscrutability, as when I respond to not terribly convincing "I'm sick" notes from interns with, "That's OK."
He may be missing the usage of the future, it seems to me, in downplaying the baffling OK, deliberate or otherwise. When used in speech, the word benefits from facial and tonal and social contexts. As our conversations move increasingly into a textual arena, OK gets stripped of these supports. The lone OK in an otherwise blank e-mail tells us only one thing for certain: Our initial message did, in fact, fly successfully through the ether and land in the intended inbox. Whether the OK surrounded by white space is also meant to convey emotion—positive, negative, or something in between—we just can't tell. Whether that uncertainty is positive, negative, or something in between is purely a matter of opinion. On the giving end, I rather like it—in fact, I couldn't do without it.
As Metcalf is well-aware, a slight and derivative book like his, on the topic he has chosen, can't help but invite the verdict that it's no better than all correct. Sure, there's a pragmatic case for a clip job like this (he's forthright about how much he's borrowed from Read), though in the era of Googling, it hardly seems urgent—and when you boil down Metcalf's own contributions, they amount to about the length of a short article.
In the spirit of that great American philosophy, tolerance, I'll admit there's merit in presenting readers with interesting questions—where did OK come from, and why is it so ubiquitous?—that they might never generate independently. Asking questions in a public forum is, after all, the raison d'être for Slate's Explainer column, which I write roughly once a week. Then again, that column caps out at around 600 words and needn't be purchased in hard cover.