I THOUGHT at first that I was simply on the wrong side of a generational divide on the idea of tweeting in church. But, at the weekend, I met someone older than me who actually thinks it is a good idea to get out the smartphone and go on social media to disseminate to the wider world the best lines from the sermon - or to cyber-heckle any perceived heresies.

It has to be said that I encountered this elderly adopter at the Christian New Media Conference, a gathering where iPads seriously outnumbered pens as the primary note-taking device.

For 2000 years, civilisation has had a love/hate relationship with technology. Socrates was even against writing, fearing that it would erode memory, and mislead us into thinking that we had acquired wisdom, when we had only information. (He was not entirely wrong there.) There were worries about the pernicious impact of printing, the telephone, radio, television, and now the internet. What history seems to suggest is that technology is neutral, and that flawed humans manage to use most things for good or ill.

Twitter enthusiasts argue that social media are part of young people's lives now; so they should be part of their church experience, too. Its impact outside church is unarguable, as the soaring price of the newly floated shares in Twitter has shown. And there is a generational divide: a recent survey of under-25s suggested that 80 per cent tweet while watching television, turning a traditionally passive experience into an interactive one.

Some in the Church are embracing this as a way of inculturating the gospel. Last year, for example, the Vicar of St Paul's, Weston-super-Mare, the Revd Andrew Alden, put up a large screen to display comments made on Twitter while his services were under way, to allow the congregation to ask questions and raise points as he preached. The internet expert Vicky Beeching argues that the Church must leave behind what she calls Web 1.0, the era when internet sites were largely passive and static, and embrace Web 2.0, today's internet, which is active and participatory. Without this, young people will drop the Church entirely.

Older heads are listening. The Bishop of London, the Rt Revd Richard Chartres, told the New Media Conference that if "cyber space is the new town square," then "the church porch is now located on the web."

Up to a point, my Lord Bishop. Someone using a smartphone in church needs to consider its impact on others. Those sitting around may become prey to irritating thoughts: is their neighbour reading the Bible on their phone, tweeting the sermon, checking their emails, texting a friend, or playing Angry Birds? Check #TweetingInChurch on Twitter, and you find entries such as "James Taylor is sitting in front of me in church right now. OMG." One priest I knew had among his congregation a member of the Cabinet who constantly cast surreptitious glances at his Blackberry, and who probably was not consulting a biblical concordance.

Apologists insist that Twitter is nowadays just a way of taking notes. It is not. It is a method of publication, and only someone self-absorbed or self-deluding would not see that. The real objection is not about poor theology, but about bad manners, as it is when the iPhone is used at the family dining table. Virtual reality can be an act of disrespect to the person present before us. Perhaps there is something theological about that, actually. It is about incarnation. And remember, it was an Apple that got us into this mess in the first place.

Paul Vallely is Visiting Professor in Public Ethics at the University of Chester.