If you suspect that your family’s cellphone bill is driven entirely by your 15-year-old, you are probably right. A recent Nielsen report shows that children aged 13 to 17 average an astonishing 3 417 text messages a month – some 45 percent of all text messages. This breaks down to seven texts “every waking hour”.

But those who look at this data and worry that young people are over-texting may be asking the wrong question. The more pertinent concern may be not the amount, but the function.

In recent years, there has been no shortage of reports about researchers who say they have found teens addicted to their cellphones. Perhaps a better way to view the data is as an illustration of how cellphones in general, and texting in particular, have taken over the experiential world of the young. An economist might expect that teens deprived of texting would simply substitute another method of communication – talking, for instance. As it turns out, a significant minority will not.

The phone is not merely a tool through which teens keep in touch with friends. It is the technology that defines their social circle. If they cannot text someone, that person may as well not exist.

The trouble is that texting arose suddenly, not gradually: Originally included in cellphones as a tool to enable service providers to spam their customers, it actually came to the US later than most of the industrialised world. David Mercer, in his 2006 book The Telephone: The Life Story of a Technology, suggests that the popularity of the practice rose sharply when viewers were urged to text their votes for the winner on such television programmes as American Idol.

This break from past practice was so radical that adults had no opportunity to work out from their own experience reasonable bounds for the young. And so the young freely created their own world, from which the old are largely excluded.

Heavy texting has been linked to sleep deprivation among the young, evidently because they somehow feel compelled to respond, even in the middle of the night. Researchers have found correlations between texting and everything from illiteracy to overeating. A 2006 study by James E Katz of Rutgers University, perhaps the leading academic expert on cellphone use, has found that young people have trouble giving up their phones, even for a short time. Most were unable to make it through a two-day experiment designed to discover what they would do without their phones.

If used in moderation, texting might help demolish cellphone etiquette, where the recipient is somehow required to make an excuse if not free to answer. Texting harks back to an earlier, less demanding model of communication, in which response was at the convenience of the respondent. It was known as letter writing.

There may actually be advantages in the use of phones for a purpose other than conversation. The proliferation of phone apps may help children learn. And for those who are worried that constant cellphone use by the young might lead to cancer, texting is obviously an improvement.

The larger problem with texting involves neither the physical nor the mental health of our growing army of young texters. My worry is that the ubiquity of texting may accelerate the decline of what our struggling democracy most needs: independent thought. Indeed, as texting crowds out other activities, it must inevitably crowd out inactivity. By inactivity, I mean: time spent in reflection. Bertrand Russell wrote a marvellous essay on this subject, titled In Praise of Idleness. Russell’s point is that when the rest of the world thinks we are idle, the brain is following its own path. Only then are we truly thinking. Unless we spend time in reflection – in idleness – we can never truly think thoughts of our own.

We live in an era when there is little time for idle thinking. As young people fill their free hours with texting and other similarly fast-paced, attention-absorbing activities, the opportunities for sustained reflective thought will continue to fade.

Today’s public debates are dominated by the short and the snappy, and influential pundits often seem to take pride in the assumption that nobody who disagrees with them can possibly have anything useful to say. We are spiralling rapidly away from that healthy democratic vision. The explosion of text messaging is certainly not a cause of the unhealthy political world we adults are bequeathing to our children. But it points to how far we are from a cure.

Stephen Carter is a Bloomberg View columnist, a professor of law at Yale University and an author. The opinions expressed are his own.