AFTER the grieving – and such acute grieving: every father of daughters who has ever waited for their overjoyed young ones in a concert-hall foyer is reeling that mass murder could befoul such a moment – comes the need for explanation.

Not retribution. How could such a thing even be achieved? Acts of terror have become so potentially ubiquitous, so immanent to our everyday lives; so much guided by ideas and memes that travel through networks and motivate the susceptible, than by the strict central command of disciplined paramilitaries.

And even if you’ve identified a “command centre” of the enemy to blow up, that very act will spontaneously trigger others to self-organise themselves into existence. If you think of it for a moment, in this connected, open and mobile world, the possibility of terrorism is exponential.

So it seems to me that the most important place to intervene is at the subjective level. What forms the consciousness and mentality which, even as it stands among the excited thousands flooding down the stairs of the Manchester Arena, can still press the annihilating button? I’ve been trying to find scholars who attempt to answer this question directly.

The most challenging is an American anthropologist called Scott Atran, who has presented to the US Security Council and is globally in demand as an adviser on counterterrorism strategy. Yet Atran’s basic findings seem as subversive as they could be of the official discourse: the one where we fight and defeat incomprehensible nihilists and death-cultists, who cynically and evilly distort world religions to their uses.

Writing in the online magazine Aeon, Atran makes this startling statement. “Despite our relentless propaganda campaign against the Islamic State as vicious, predatory and cruel – most of which might be right – there is little recognition of its genuine appeal, and even less of the joy it engenders.

He continues: “The mainly young people who volunteer to fight for it unto death feel a joy that comes from joining with comrades in a glorious cause, as well as a joy that comes from satiation of anger and the gratification of revenge (whose sweetness, says science, can be experienced by brain and body much like other forms of happiness).”

Atran has conducted much field research and many interviews – among captured Daesh militants from Iraq and Syria, as well as with youth in Paris, London, Barcelona and Casablanca. He concludes that “more than 80 per cent who join the Islamic State do so through peer-to-peer relationships, mostly with friends and sometimes family. Very few join in mosques or through recruitment by anonymous strangers.”

As Atran put it to the Security Council in 2015, the world’s most lethal killers are motivated “not by the Quran and the teachings that surround it”, but by “a thrilling cause and a call to action that promises glory and esteem in the eyes of friends”.

Most of his interview subjects have a very partial understanding of the religion they invoke. And if we are focusing on foreign volunteers for Islamic State, they are often “youth in transitional stages in their lives – immigrants, students, people between jobs and before finding their mates. Having left their homes, they seek new families of friends and fellow travellers to find purpose and significance.”

Consider the bare bones that we know of the wandering, drifting life of the 22-year old Salman Abedi. Trips to the Middle East interspersing with abandoned local college and university courses. Engaging with Manchester criminal gangs, alienated from his local mosque, living at home while his parents return to a Libya from which they were exiled under Qaddafi. So far, all of this fits well with Atran’s social and psychological model for jihadi extremism.

Atran dives back into the historical record, seeking to frame these murderous pathologies as not unprecedented, and not just the work of monstrous “others”. Robespierre, the guillotine-happy brute of the French Revolution, still chills with this quote from 1794: “Virtue, without which terror is destructive; terror, without which virtue is impotent. Terror is only justice prompt, severe and inflexible; it is then an emanation of virtue”.

Atran also shows how jihadis are rendered in the same ways as “anarchists” were the cusp of the 19th and 20th centuries. In response to their random attacks on “bourgeois” cafes, the US President Teddy Roosevelt said: “When compared with the suppression of anarchy, every other question sinks into insignificance. The anarchist is the enemy of humanity, the enemy of all mankind; and his is a deeper degree of criminality than any other.” This may sound familiar to you.

History shows it was the organised communists who eventually diminished the random destructions of the anarchists. And some of the most fascinating quotes from Atran’s research hint at what may lurk on the other side of the “Management of Savagery/Chaos” (the title of a 2004 manual that is often cited as Islamic State’s strategy book).

TO be clear, these plans are horrorism, not just terrorism. “Hit soft targets. Strike when your victims’ guard is down (to maximise the draining of their security resources). Capture the rebelliousness of youth. Draw the West into your quagmire.”

But Atran also speaks to an imam in Barcelona: “I am against the violence of Al Qaeda and ISIS... but they have put our predicament in Europe and elsewhere on the map. Before, we were just ignored. And the Caliphate ... We dream of it like the Jews long dreamed of Zion. Maybe it can be a federation, like the European Union, of Muslim peoples. The Caliphate is here, in our hearts, even if we don’t know what real form it will finally take.”

This is a hard rationale to swallow, even if we might wish the “anarchists” of radical jihadism to become “communists”. But it’s difficult to imagine how we Westerners could do anything to foment their emergence, given our historical and current record in the region.

However, if you accept this thesis, by this time you will be looking for some indications of an appropriate response. What won’t work are “hackneyed appeals to ‘moderation’”, notes Atran tartly, “falling flat on restless and idealistic youths seeking adventure, glory and significance”.

But what might work, he suggests, are youth-initiated organisations like the United Network of Young Peacemakers, and Aware Girls (started by two teenagers Gulalai and Saba Ismail). Based in Pakistan, they’ve been very successful in turning young males away from the Taliban.

The localism of these initiatives is very important. Atran deplores the blunderbuss ineffectiveness of traditional Western persuasion and prevention strategies, which in a recent paper for Science he says are “trapped in paradigms of foreign policy, military doctrine, and criminal justice, each with serious drawbacks when applied to terrorism”.

Of course it’s hard to hear from academics on subjects like this at times like these. But if we genuinely wish to “Prevent”, as the UK Government anti-radicalisation programme has it, we may have to adopt the anthropologist’s stance.

As Atran put it, in his most challenging formulation, we must “empathise with those most different from one’s own moral culture, without necessarily sympathising. This is our call to comprehend. If we can only grasp why otherwise normal humans would want to die killing masses of other humans who have harmed no one, we might ourselves better avoid killing and being killed.”

It is completely understandable that the non-academic mortals among us might prefer to turn our empathies in a different direction, just for the moment. To hear a multi-ethnic Manchester crowd break the silence of their vigil with a spontaneous rendition of Oasis’s “Don’t Look Back In Anger” overwhelms you with emotion.

It easily commits you to pointing your trembling heart in the direction of love rather than hate, directed at as many fellow and various citizens as you can manage – and damn the details of any social-scientific findings.

But these weapons are triggered by humans; these humans are social, already among us; and they are also like humans who have been extremists in history, under conditions we may readily recognise.

Let us mourn the beautiful children and adults of Manchester, and mourn hard, openly and sustainedly. But we must comprehend too – all the better to reduce the chance of mourning this painfully again.

ISIS Is A Revolution, by Scott Atran, is on