Cathedrals belong to everyone. In vox pop interviews in secular France after the Notre Dame fire we heard so often: “I’m an atheist, but Notre Dame is part of me.” Reactions in Britain would be the same: a great cathedral stands for so much more than religion, narrowly conceived. It represents human skill, the quest for beauty and the continuity of communities over a length of time far greater than even many lifetimes. Attendance at cathedral services now bucks the national downward trend in the Church of England, but does not necessarily signal a widespread conversion to Christianity.

At Easter, it seems natural to commentators to speak of the resurrection of the damaged cathedral, or to use the image of the phoenix reborn from its own ashes. Resurrection, too, is so much more than a religious symbol. In the northern hemisphere it has associations with the resurgence of nature – hence daffodils and bunnies – and speaks to the universal wish that death could somehow be defeated.

Christianity began as a small Jewish sect whose focus was on the alleged resurrection of Jesus, a Galilean teacher and healer. It’s obvious to anyone reading the New Testament that this sect survived only because it believed Jesus had risen from the dead. It had no raison d’être apart from celebrating, and trying to persuade other Jews, and then non-Jews too, of the truth of this improbable claim.

But what did they mean by “resurrection”? When lightning damaged York Minster in 1984, some misguided religious commentators thought it a divine punishment because David Jenkins, the controversial bishop of Durham, had recently been consecrated there. He had referred to the resurrection of Jesus with the expression “a conjuring trick with bones”. Few noticed that what he actually said was that it was not a conjuring trick with bones but the phrase stuck to him thereafter. What he meant was that the resurrection was not the reanimation of a corpse, but something much more mysterious.

It was also something much more important. A corpse coming to life would be a miracle, no doubt, but it might not mean anything. It might be a random freak event. Early Christians believed that the resurrection of Jesus meant a transformation of reality, despite the fact that other Jews pointed to the fact that reality did not seem to have been transformed in any measurable way. Christians clung to the belief that something vitally new was happening in the world, and associated it with Jesus having been granted some kind of new life that would never end.

Jesus is taken off the cross in Pieta, by Rogier van der Weyden (1399-1464). Photograph: DEA/A. DAGLI ORTI/Getty Images/DeAgostini

What that new life consisted of, they could not precisely say. No early Christian accounts purport to describe the event of resurrection, yet all associate it with the belief that the resurrected Jesus had “appeared”. However, the accounts do not even agree on whom he appeared to. It seems obvious that legendary elements have been mingled with a memory of some kind of cataclysmic experience that could not be adequately described. Something must have kickstarted the early Christian movement, yet its leaders appear unclear exactly what it was: they can only call it Jesus’ resurrection, without telling us what that really amounted to.

The gospels exist because some Christians decided that they must record who the resurrected person had been in his lifetime. The resurrection of just anyone might not be good news – Nero, say, or Pontius Pilate. The nascent church needed a profile of Jesus that would show why his resurrection was “gospel” – glad tidings. But with the same maddening lack of clarity, what it got were four divergent accounts. The stories in the gospels do not merely supplement each other, but sometimes conflict. This is true of the stories of Jesus’ birth as much as of his resurrection. In Matthew, Jesus and Mary live in Bethlehem and only move to Galilee to escape Herod, whereas in Luke they go from Galilee to Bethlehem for the census. And the story of Jesus’ life and work before the last week of his life varies greatly among the gospels.

Yet for all their confusions, all these stories have become central to western culture. Popular devotion has smoothed them out, and has treated them as “gospel truth” – historically sacrosanct, despite the doubts that many individuals may harbour about some of their details.

The gospels were not written as parts of a bible, but as alternative ways of describing the character and sayings of Jesus. They, too, are paradoxical. On the one hand they were not seen as scripture, in the way that the Old Testament was, but simply as memoirs, sources of information about the earthly life of Jesus.

They were not written in the solemn scroll format of scriptural or high-cultural books, but on codices bound down one side – what we now think of as normal books. At that time the codex was an informal format, used as a notebook rather than a vehicle for serious literature. On the other hand, their contents were regarded as even more important than what was in the Jewish scriptures, the Old Testament or Hebrew Bible. This was because they described what Christians were sure had been a special divine intervention in the world – in the life, death and resurrection of Jesus.

These old stories flicker in and out of focus as we read them. Every time we ask them to give us solid fact and unambiguous testimony, they disappoint. The New Testament is no definitive document, but a series of slanting beams of light on something that always just eludes our gaze. But its sense that God will ultimately bring life even out of death continues to resonate even among many who could never commit themselves to a religious faith yet sense that there is something here that requires investigation and promises hope.

I have a cartoon on my wall showing a small church with a notice outside reading “Important if true”. Reading the New Testament books will not necessarily convince you that it is true. But it is likely at least to leave a sense of yearning for new life beyond the deaths that we, and even our most valuable cultural icons, are bound to suffer eventually.

•Professor John Barton is the author of A History of the Bible