Will evangelical Christianity take over the world? I do not think it will, but then I would say that, because it is not my sort of thing. That, however, has little relevance. I do not have a television, but still television has taken over the world. I do not belong to Facebook, but Facebook has still taken over the world.

In South America, where I live, we have a great deal of evangelical Christianity. Brazil has seen Pentecostal churches like the Assembléia de Deus stride across the country with giant steps, dwarfing the historically enormous Catholic church (to which I belong). Here in neighbouring Paraguay, we are behind the rest of the continent in the Pentecostal advance, but it is growing. This Sunday I went to the biggest evangelical church in Asunción, called the Centro Familiar de Adoración, which has a new building seating ten thousand people (yes, ten thousand). People from the CFA do excellent work, in particular running a chain of lunch clubs for the children from the poorest barrios.

I was greeted at the door with an information leaflet and an affirming greeting, "Blessings on you, sister". Inside what was going on was like a television show: five young men and women with microphones were dancing and singing on an enormous stage while electric guitars and drums pumped out loud music. Close-ups of the faces were projected onto huge screens, and the congregation were waving their arms in the air. The song changed to an emotional slow movement, with words of yearning to express the sanctity of the Almighty. Then there was a time of healing – "God is doing something big, now, in this place, now, now, now..." (whoops of excitement from the floor). And then all the first-time attenders were called forward for a blessing, and shepherded out for counselling from a team of church leaders in small rooms, where they were given a leaflet, "Advice for a new life".

There is no sacred symbol of any kind in this megachurch: no cross, no coloured focal point, no pulpit, just a vast stage, a clear perspex, movable lectern with a bible on it, and banks of seats behind for musicians and choir. A team of about 30 pastors were presented, coming in husband-wife couples – a pastor and a pastora. The men were all in suits and the women were all elegantly dressed – as though for a show. The preaching was all done by men, who used a lot of gestures and body movement to get their message across. There was a condemnation of Marx and of Nietzsche. The phrase "The bible says..." was often repeated, and the texts projected onto the walls were lacking in any inculturation, using the vosotros form for "you", which is never used in South America unless in church texts imported from Europe. The service lasted two hours.

Is this the wave of the future? I can see the attractive points. The sense that you have been present at an event where something transformative has happened – not in this case the transformation of bread and wine, but the action of the Spirit - "now" – "wow!" – in a huge crowd of people of which you have been privileged to be a part. The thump and rhythm and lovely clothes of a television-style show. The personal attention to every individual – personally greeted, personally cherished and followed up. The evident good works that sprout out of this community – infectious love, inspirational concern for others.

Evangelical Christianity has already opened wide its arms and its heart. I just hope that it will also open wide its mind. The Bible is indeed the word of God, full of wonderful quotes that can be repeated over and over; but it has been written through the medium of a long human process, and is not a series of God-dictated propositions that can be stuck together in any order. The unity of the church is seen not just in huge congregations and massive international events: it is also seen in the continuity of the church through history, held together in the focus of unity known as the apostolic succession. A fully integral body-and-soul response to God's word involves more physical actions than dancing on stage, waving arms in the air and falling over with the power of the Spirit: it can also include genuflections, the splash of holy water, making the sign of the cross, and the full Catholic range of sacraments and sacramentals.

It is good to see women standing side by side with the men and not excluded from visible leadership, but women are individual leaders as well as complementary partners. It is desirable to have pop and rock liturgical celebrations, but sacred music has a wide range and history, including Gregorian chant and European classical music. It is excellent that the evangelicals have learned to locate the church in people and not depend on sacred buildings, but two millennia of the Church's iconographical and architectural tradition cannot be left aside like some kind of superstitious aberration.

Perhaps in the end evangelical Christianity is a stage in the church's growing up – necessary, desirable, to be applauded, but the prelude to a wider wisdom and a greater maturity.