The Charlie Hebdo offices after the attack/Wikimedia

Here are the rules: don't put anything in an email. In fact, don't put anything in any kind of online message. Don't discuss anything on the phone. In fact, don't have any phones in the room when you discuss things. Talk only in person, only, usually, in small groups of people you trust.

I mention this because the Sun, and many others, seems to think that an appropriate reaction to a murderous attack on freedom of speech is to call on the state to read our emails. The truth is that avoiding online surveillance is dead easy: don't organise online. Suggesting that you can catch terrorists by reading what they say on the internet is rather like saying you'll find burglars by following them on Twitter: it's only a way to seek out the really stupid ones.

But that's not really the point. Because whatever the rights and wrongs of mass surveillance, the shootings in Paris this week were an attack on freedom of speech. There is a deep irony in using it as an opportunity to call on the government to monitor what we say. “They've attacked our freedom of expression”, the Sun is effectively saying “and so it's vital that the security services know your every thought”. Britain used to be famed for our sense of irony. How the mighty fall.

But the Sun only compounds its sins. “They cannot be understood”, they say. If that were the case, then what would be the point in our intelligence agencies? In truth, the attack on the offices of Charlie Hebdo is very revealing. If the the perpetrators were (as now seems almost certain) Islamist extremists, then they add to a trend we've seen in recent years.

Where in the past, the modus operandi of violent Islamism was random killing on the biggest scales they could manage, there has been a shift. The suicide bomb has been replaced by the AK47. The hijacked plane has been swapped for the machete and the meat clever. Now, attacks are targeted. From Woolwich to Jerusalem, modern Islamist violence tends to be more focussed. The Sun paints a picture of hot-headed madmen, when in truth, we are dealing with calm, methodical killers. It's a shift that my brother, Gilbert Ramsay, has been monitoring in recent years in his work at St Andrews' Centre for the Study of Terrorism and Political Violence.

And when such murders are so targeted, when they've considered their actions so carefully, that gives us a good stab at trying to work out what the attackers want. Here's what I reckon. They want to polarise our communities, so that we turn on each other. They want to make most of us more racist, more Islamophobic. They want to push liberals into republishing cartoons that offend Muslims and to make Muslims feel more isolated, more afraid. They want to create martyrs for their enemies to rally around. They want secular Europe all to be Charlie Hebdo, all to go out of our way to offend. Because that's how they plan to bait the majority into driving more recruits into their arms. That's how they plan to break apart our multicultural communities. Polarisation is always good for those on the fringes, and they know that only too well.

So the Sun is exactly wrong. We should not respond to an horrific attack on freedom of speech by demanding that the state more carefully monitor what we say. We shouldn't confuse a targeted assassination with a random hot-headed killing. Eleven people were murdered this week. They'll be defeated with compassion and intelligence. Unfortunately these are not traits for which Britain's biggest selling paper is famed.