Imagine a world in which every knife has been replaced with a Swiss army knife. Think of all the things you can do with a good Swiss army knife! You can cut rope. You can open a bottle of wine. You can screw two boards together. You can cut your fingernails.

The only problem is that you cannot do any of these things very well. In particular, a Swiss army knife—in spite of its name—is not a very good knife. It is useful for opening a box, but you will reach for something else if you want to cut a steak. You will reach for a thing that is dedicated to the business of cutting, and does the job well.

In a world where all our knives had suddenly become Swiss army knives, you would get your steak cut eventually, but it would be a frustrating experience. It might be frustrating enough that eventually you would give up on steak and find something else to eat. The giving up would probably not happen all at once; you would never explicitly decide to give up on steak; but every time you thought of eating steak, you would think of the trouble and effort it would cost you, and you would be more and more likely to try hamburger instead. You might not like hamburger as much, but you can hold it in a bun and leave your Swiss army knife in your pocket.

In the end, in this hypothetical world of Swiss army knives, you would probably be reduced to consuming only things that you could eat with your hands, or things that could be effectively handled with a Swiss army knife. Bit by bit, your habits would adapt to the tool you had available. If the corkscrew was fun to play with, you might develop a drinking problem.

In our world, we have not replaced all our knives with Swiss army knives. But we have replaced our telephones with smartphones, and our little thought experiment will help us understand the effects of that change.

The smartphone is a tool that fits in your pocket and does everything, but the corollary is that it does not do anything very well. It has a Web browser; you are limited to what will fit on a small screen, but that is enough for Wikipedia to settle an argument about the exact dimensions of Jennifer Lopez or whether tiger swallowtails are man-eaters. You can send text messages and emails; the little virtual keyboard is cramped and inefficient, but it does the job. If you are persistent and something of a masochist, you can even get some writing done with a simple word processor. You can take pretty good pictures with the built-in camera. You can listen to music. You can watch a movie. None of these things can be done as well with a smartphone as they can be done with dedicated tools, but the dedicated tools do not fit in your pocket.

Finally, you can even talk on a smartphone. But you cannot do it very well. Dr. Boli has mentioned this before, but it is worth dwelling on: if what you want to do is talk, the 19th-century technology that runs our few remaining wired phones does a better job than our 21st-century cell phones do.

Dr. Boli estimates, and he is backed up here by extrapolation and imagination, that our economy loses tens of billions of dollars a year to cell-phone misunderstandings. Comedians reach for the voice-breaking-up joke in every routine, because it is a universal experience. You may recall, if you are old enough, that twentieth-century comedians loved the phone as a prop, but bad-connection jokes were few. Too many would have been implausible; it was simply too rare an experience to have an inadequate connection.

And yet the 19th- and 20th-century telephone was a poor tool for its job. The limited range of sound made it impossible to distinguish S from F, or K from T. The fact that we have settled for worse sound and less reliable performance for the sake of convenience tells us something about our culture.

And bit by bit we are adapting to that decision we made. The telephone is being retired as a telephone. Voice calls are becoming rarer, because they do not work very well for most of us. Oddly, we can do effective videoconferencing with these smartphones of ours, but we have a hard time making simple voice calls work.

One of the unforeseen effects of the smartphone revolution has been an extension of the domination of the written word. In the late 20th century, it was not hard to find pundits who would predict the imminent end of writing as a tool of communication, except for specialized uses. What happened instead was that everybody became a writer. Most of us did not become good writers, but we all began sending text messages hither and thither through the ether, many of us accumulating thousands of words a day in written communication. Text messaging was attractive because it is much more reliable than voice calls. If you send a text message, you know that it arrived at the recipient's phone in exactly the same state as when you sent it. There are mechanisms to make sure of that. Your voice may sound very different at the other end of the call, but if your text message is misunderstood, you have no one to blame but yourself. (Or, of course, the recipient, for being too stupid to understand a simple dancing-rat emoticon.)

Another obvious effect has been to make us a culture of one-liners. Text messages, Twitter, and Facebook all discourage reasoned argument. If you cannot say what you have to say in the number of words that will fit in a little talk bubble on a phone screen, then what you have to say simply will not be heard. Dr. Boli is not misty-eyed with nostalgia for the good old days when ordinary Americans settled their differences with reasoned discussion and carefully marshaled arguments, because those good old days never existed. Ordinary Americans have always settled their differences by hurling insults, and, when those failed, brickbats. But it is true that now even our pet intellectuals are forced to speak mostly in one-liners. If they do not, they are no longer our pets. Our universe is a New Yorker cartoon.

What are we to do about all this? Nothing, obviously: market forces have taken command, and they will lead us whither they please. It makes one nostalgic for the lovely old Soviet Union, where technology that worked continued in use for decades, because there was no market incentive to make superficial improvements to what was already quite adequate. But the Soviet Union had its own little cultural difficulties.

So if you, like every patriotic American, are the proud keeper of a smartphone, you might consider how to make the best use of it. Do you rule the phone, or does the phone rule you? How much of what you are—your actions, your conversation, your thinking—is dictated by the little black slab in your pocket? And what can you do to get out from under its thumb?

Dr. Boli has a suggestion, but it may be subversive, so look both ways and lean close. This will alert Homeland Security that you are up to something subversive. Now here is the suggestion: Go for a walk without the phone. Start easy—perhaps just fifteen minutes. Work up to half an hour or even an hour.

You may discover after a while that your phone does not need you as much as you thought it did.