What is it that modern civilisation most lacks? What are the fundamental deficiencies that ultimately could undermine it? Pope Francis has come up with a profound answer that seems at first glance too insubstantial, even naive, to save the world from itself. Not a major source of new energy or fresh food supply; not even a cure for cancer. What the world needs is the realisation that every member of the human race is brother or sister to every other member, no matter how distant or unfamiliar.

In his latest encyclical Fratelli Tutti – the phrase is from the writings of his namesake St Francis of Assisi – the Pope closely argues an increasingly convincing case that social division, fragmentation and the friction they cause are the primary threats that humankind has to fear. That includes the possibility of unprecedentedly destructive wars, but is not limited to it. The entire environment is at risk. And the cause is the absence of a sense that human beings all belong to the same family, and hence to one another. “We need to think of ourselves more and more as a single family dwelling in a common home.”

This is not some unreal utopia, however, where differences melt away in a warm wash of togetherness. Identity is local, and local loyalty matters. To use an English expression that Pope Francis is probably unfamiliar with, charity does indeed begin at home. But it ends at the ends of the Earth. Local identity is necessary and good, but is also a trap if it labels the others, those not of that tribe, as less than human. He analyses at length the parable of the Good Samaritan, and uses it to show that no one is an island but each of us is a piece of the human continent. All are neighbours to all; all are therefore covered by the injunction “love thy neighbour as thyself”.