Would Islamic State have attacked Paris twice this year killing almost 150 people if France weren't bombing it in Iraq and Syria?
Would IS have blown up an airliner killing 229 Russian tourists and aircrew, if Moscow had not intervened in Syria?
Would IS have bombed Shi'ite suburbs of Beirut killing at least 43 if Hezbollah was not fighting alongside President Assad's forces?
Would IS have launched attacks in Turkey killing 134 peace protesters if Ankara had not turned against it over Syria?
I'm not asking these questions to imply the victims of these attacks somehow brought it on themselves.
I'm asking because as President Hollande said this week his country is "at war" with IS - it has been since it started air strikes against its forces last year - and in a war you are likely to get attacked.
I'm also asking because when IS - or ISIL or ISIS or Daesh - hit world headlines by seizing Iraq's second city, Mosul, last year, the conventional wisdom among the experts and analysts was that IS was a different kind of threat from al Qaeda - whose signature is mass casualty terrorist attacks, anywhere it finds a target, like the 9/11 attacks in the US or the Bali bombing.
It may have emerged out of al-Qaeda in Iraq, but the argument went that ISIS - the Islamic State in Iraq and Syria - was what it said on the tin - an organisation dedicated to carving out a state from those two countries.
It followed from there that IS was fighting a more conventional style war with the aim of capturing territory. Sure it used terror against its enemies by publicising on social media the atrocities it carried out when it occupied towns and took prisoners - be they regular Iraqi troops or Yezidi women and girls - but it was not interested in attacking targets further afield.
If this was a correct reading of IS then, we now know only too well it isn't anymore.
It is tempting to see IS attacks outside Syria and Iraq as a direct response to the intervention of foreign forces against it that began after the fall of Mosul and its advances across the border in Syria.
But one of the first such incidents linked to IS was the attack on the Jewish Museum in Brussels in May 2014 - before the fall of Mosul and several months before the US-led campaign against it began.
Whatever motivated the change in tactics by IS, the conventional wisdom has been proved to be very wrong.
With the escalation of terrorist strikes and the shock of its assault in the heart of a major western capital, the focus is on how to eradicate the Islamist group.
Here another piece of conventional wisdom comes in - that destroying Islamic State in Syria and Iraq can be achieved, but only by using large numbers of ground troops.
Syrian and Iraqi Kurdish forces backed by US air strikes have had some success and recently retook the town of Sinjar. But the Iraqi army and its Shia militia allies have made heavy weather of retaking Ramadi and the much-awaited offensive to retake Mosul is still to get underway. They clearly need reinforcements though where they may come from is another matter.
But is this wisdom also flawed?
Is there the danger the defeat of IS in Syria and Iraq would see it resorting to more mass casualty attacks in the region and beyond?
Remember, after 9/11, the overthrow of its Taliban hosts in Afghanistan didn't prevent al Qaeda and its followers around the world carrying out further terrorist attacks, including Europe's worst to date: the 2004 Madrid train bombings that killed more than 190 people as they travelled to work.
The challenge many European countries face is that they have quite a few young Muslim citizens who are attracted to Islamist ideology.
This seems to be because they are deeply alienated from mainstream society and deeply angry about what they see as their countries' policies towards the Muslim world.
But being attracted to the ideology and carrying out acts of terrorist violence for the cause are two different things.
What makes some people take to bombing and shooting their fellow citizens is not yet well enough understood. The studies that have been done suggest it's a complex combination of societal and psychological factors as well as ideology.
Whatever the precise triggers, European countries, like France and Britain, are grappling with a volatile mix - the legacy of their imperial past in the Middle East and North Africa added to recent policies in the region which have angered substantial numbers of alienated young Muslim men and women.
The final ingredient - the detonator - seems to be the appeal of groups like IS offering what to these young people may appear a romantic cause of fighting to restore a glorious past - in this case the Caliphate.
So alongside more effective security measures and increased vigilance from ordinary people, to stop further attacks European countries need to take a deep breath, not overreact to Paris, and try to address the causes of Islamist violence.
So far the prospects don't look good.
The French and British governments are both proposing changes that will enhance powers that will restrict people's freedom.
Yet, French politicians and commentators have echoed their counterparts in Britain and other countries that have suffered Islamist-inspired violence by saying the terrorists' target is the European way of life. So, surely the worst response would be to resort to unreasonable restrictions on people's rights and freedoms in the name of defeating IS?
If this is partly an ideological struggle, that would be conceding valuable ground.