OPINION: As the Lindt cafe coronial inquest opens, we again ask ourselves the same questions. How did it happen? Could it happen again? And how might a recurrence be prevented, or at least discouraged and rendered less likely?

Here, increasingly, the remedy, or buzzword, we are offered is “deradicalisation”. Whether such an approach is likely to yield positive results needs to be faced clearly and honestly.

If a repeat of the Sydney atrocity is attempted, it may be the project of a psychotic loner. In that case there is little to be done. What remedy or prophylactic we may have lies with our mental health system and the ability of the ­nation’s security establishment to grasp and act on those clinical findings.

But most such incidents are the work of psychotic, sociopathic, disturbed or even ostensibly normal individuals who fall in with, and whose ideas and perverse impulses mesh them into, small like-minded groups, sometimes even broad social movements.

In these cases the question becomes: what is the relation between the mindset of the small group and that of the mainstream from which they emerge and against which they may stand? Are the orientations and outlooks basically the same, or at least compatible and congruent? Or are the outsiders really deviants who have turned against and repudiate the intellectual, cultural and political milieu that spawned them?

Where they have departed decisively from the broader norm, they may perhaps be brought back into the community’s fold by efforts directed at some kind of thought-reform, faith rectification or intellectual realignment and reabsorption. That, broadly, is the strategy of deradicalisation.

But when the source of such potential violence — namely its basic outlook and driving attitudes — is not distinctive to the breakaway group, as some kind of outsider heresy, but lies within the wider group and its familiar doctrinal furniture, deradicalisation must be an unpromising strategy. Here it can offer little hope of success since the community mainstream and its insiders have no independent and distinctive moral ground of their own on which to stand, and to which they may call back the deviants to the ways of sound thinking and belief.

Which of these two situations better typifies the relation of the militant and potentially violent Islamists to the mainstream community norm and its faith patterns? Here it is the latter, with all its unpromising implications and prospects for successful deradicalisation. Why so?

Among Muslims worldwide today, about 10 to 15 per cent, it may be suggested, are modernist, reform-minded and democratic; perhaps another 10 to 15 per cent are militant, radical, extreme and potentially active in violent forms.

Between these two clusters, the 70 per cent in the middle represent what may be called conventional or quasi-traditional Islam.

The question is: what is the relation of the views of the radical extreme to those of the centrist mainstream? Are they opposed, a deviationist breakaway, or are they basically identical, or at least complementary?

It would be reassuring if things were otherwise, but the basic facts are clear. Like the radical fringe or fundamentalist extreme, the Muslim mainstream adheres to, through explicit affirmation or by unreflecting habitual assent, the same underlying propositions that constitute the radical and militant world view. Like that of the militants, their Islam, or view of it, is basically supersessionist.

That is, they hold, as core Islamic doctrine has held from the outset in its Koranic foundations, that Islam embodies and carries forward all that was once good in Judaism and Christianity (a fact that now makes those predecessors superfluous and lacking in continuing spiritual value and authenticity); and that what it does not carry forward from them is not good (and was the expression of an earlier, incomplete and defective revelation or else the result of the subsequent faults, sometimes wilful, in the recording and transmission of the sacred revelation by rabbis and priests).

And it is triumphalist, holding the view that Islam succeeded in the world, notably in its engagements and confrontations with the worlds of Judaism and Christendom, because its belief system was superior (and its long-lasting political ascendancy was conversely seen for a millennium as the proof and vindication of Islam’s religious superiority). While the power of Islam may have been eclipsed during the past two or three centuries, the subordination and shame of Islam is temporary and ultimately will be reversed.

Many Muslims, not just the militants but those throughout the mainstream or centre ground of their faith community’s social spectrum, chafe against the ­humiliation the world of Islam has experienced in modern times at the hand of non-Muslims, believe this situation must and will be reversed, and that determined action on the part of the faithful is necessary to bring about that ­divinely ordained historical restoration of Islamic dignity, autonomy and even ascendancy.

The mainstream and the militants, including the violent implementers of militant ideas, share this outlook. The difference is simply, or largely, one of the means and measures and strategies that different kinds of Muslims are prepared to countenance in realising Islam’s divinely vouchsafed historical destiny.

The implication is clear. Since the radicals and the mainstream share — if in different forms and style and emphasis — the same religiously grounded historical world view, the two orientations are basically complementary and congruent, not opposed. So there is no ground within the mainstream for calling back the deviant minority; no distinctive standpoint, authentic and authoritative, to which the radicals may be called to return by abandoning their own identifiable heresies. The moderates from the centrist mainstream stand bereft of the religiously based political and moral authority to make such calls persuasively, in ways that may prove enduringly convincing.

How has this situation come about? In short, the Abrahamic faiths and faith communities of Judaism and Christianity, or least key aspects and large parts of them, have been enlarged and transformed by their engagement with liberal modernity. This is not the case with Islam.

By contrast, most major modern trends in the faith and among its adherents have been shaped, if anything, by the history of their painful, and much resented, subjugation to Western-generated modernity — social and economic, technical and administrative, cultural and intellectual, as well as military — and by the long history of Islamic resistance to that domination.

Those are the facts and experiences that shape the soul and mind, the historical awareness and sensitivities, of modern Muslims everywhere; and those too, when held and expressed as powerfully felt resentments, are what drive the actions of Islam’s militants. Militant Islam does not depart from and repudiate the Islamic mainstream and its presuppositions. It replicates and echoes and affirms them in an amplified and disturbing fashion.

So long as the two outlooks remain basically congruent and complementary, so-called deradicalisation of the militants back into the mainstream cannot work. It is not a likely prospect. It cannot succeed so long as the mainstream is not distinctively different in its basic attitudes from the radicals.

That will remain the case, with its unpromising implications for the strategy of deradicalisation, so long as the Islamic mainstream ­remains unreformed and untransformed in its basic presuppositions; so long as it remains an outsider to modernity, so long as it shuns rather than embraces the emancipating and individualising spirit of advanced modernity.

So long, that is, as mainstream Islam retains, implanted within it from the long evolution of Islamic civilisation, the same supersessionist, triumphalist and resentfully restorationist outlook that frames and drives militant Islamist action worldwide.

Thoughtful, modernising, liberal and democratic Muslims well understand what the problem is here, and they have shaken themselves loose from those attitudes. But they have not succeeded in detaching the mainstream Muslim majority and its thinking from those enduring ideas and that defining orientation.

They have not just failed, despite their heroic efforts, to uproot that kind of thinking; worse, they find themselves stigmatised, marginalised and scandalised for their attempts.

The tide has been running strongly against them in the world of Islam during the past half-century, which has witnessed a return to Islam “as the solution, not the problem” and a reaffirmation of Islamic identity in a variety of forms of Islamist politics.

Increasingly, the militants and the mainstream share a common mindset and set of attitudes. The difference is that those in the mainstream tend to accept and go along with them habitually, while the radical Islamist ideologues take those framing ideas seriously and literally, and seek to affirm them actively. They seek to enact and perform and so make those ideas real and, in that way, to make them prevail politically. The ideas of groups such as Hizb ut-Tahrir are simply that more generalised and often vague mindset made explicit, formalised and ideologised as doctrine. They offer it as sacred theory. Militant jihadi Islam goes a step further: it represents that same idea, that theory, activated and rendered in violent practice.

If this is the case — and no serious argument has been made against it as there has been no recognition that this is the nature of the problem — then community-based, community-supported and community-driven strategies of deradicalisation cannot work. They are doomed from the start.

“Fight the terrorists by partnering with Muslims and their communities” is the mantra of the counter-terrorism experts and the deradicalisation gurus to whom they turn. Of course one would, if and when that is possible. Of course it would be better to work with, rather than without or against, the Muslim community and its leadership. But to whom can one turn when there is this blurring and overlap between the outlook of the mainstream and the radical extremists?

The best to whom one may turn may be none too good. Earlier this week a leading community leader voiced the view that the former grand mufti of Australia Taj Din al-Hilali had been a misunderstood voice of moderation.

Such views are endorsed from within our universities where scholars specialising in Australian multiculturalism opine that Hilali — his execrable view of Jews as a poisonous and corrupting influence on societies throughout history notwithstanding — has been a notable force for interfaith ­dialogue and conciliation in this country.

What is needed is not, as the deradicalisation paradigm and strategy suggest, an effort to save the supposed dupes and victims of “bad Islam” by offering them conventional mainstream Islam as a “good Islam” antidote.

Doing so does not transform or re-educate the radicals. It cannot enlarge their militant outlook or wean them from it. It can, at best, only leave the militants unaffected or, at worst, serve to reaffirm and revalidate the foundations of their stance — while convincing them the mainstream are no better than weak-hearted hypocrites for voicing views they dare not unreservedly promote and implement.

Restoring the militants to the mainstream seen as “good Islam” does not even start to confront or uproot the underlying attitudes that drive radical Islam, as those attitudes are themselves inherent and ingrained within the mainstream mindset and outlook and its basic assumptions.

Mainstream attitudes, unre­formed, simply conduce, or at least can readily conduce, towards radicalism and its reinforcement, not to deradicalisation.

This will remain the case so long as Muslim minority communities in the Islamic diaspora in the West, such as in Australia, continue to act from and on their conventional outlook and historical consciousness.

Which is to say, so long as they continue to perceive their situation and engage with the wider world of which they are now part on the basis of conventional Islam’s “majoritarian” and “governmentalist” attitudes: the idea that ours is a society in which Islamic requirements must prevail, such as the view that it is impermissible to offer generally, and hence for Muslims to be faced with, depictions — even ironic depictions— of the Prophet Mohammed; and similar ideas that are basic to the supersessionist and ultimately triumphalist, restorationist and retributionist outlook that is embodied in conventional Islamic historical consciousness.

If deradicalisation won’t work, people may ask, what will? Don’t just be negative, some urge, suggest something positive, a way forward. What needs to happen is clear, but how to bring it about will be no simple thing.

What needs to happen is first, there must be some serious, honest and deep discussion of these matters among Muslims speaking to one another not as Muslims but as Australian citizens.

Second, there needs to be some honest and serious and responsible discussion of these same matters within the wider Australian community. For that to happen, the possibility of, the need for and the legitimacy of such discussion needs to be acknowledged.

What that means is that the formal barriers and informal inhibitions thwarting responsible and constructive public discussion throughout Australian society of Islam, and of the Islamic civilisational legacy within and as a part of world history, need to be removed.

And third — ultimately, perhaps beginning only gradually and carefully — those two parts of the discussion of Islam as a matter of legitimate interest to all Australians and to Australian society as a whole need to be brought together. Not necessarily on a view that they should immediately become one and the same, but that they may connect and engage with one another. Both sides stand to benefit from that kind of exploration and negotiation of religious and cultural differences, and convergences, framed on both sides by some encompassing ideas of Australian citizenship and of membership in our national community.

But that is not what is happening. It has yet to begin. Meanwhile, we talk instead of deradicalisation. Offered as a rescuing strategy, deradicalisation may be only an unfounded hope, perhaps even a forlorn fantasy.

Clive Kessler is emeritus professor of sociology and anthropology at UNSW.

This opinion piece was first published in The Australian.