The death threats come with the territory. Since the advent of the internet, people around the world who are disgusted or enraged by my cartoons have been able to threaten to kill me via email. Over the years these have included Muslims, Zionists, Republican Americans, a few angry Chomskyians, Catholics, Russians, some Serbs and, I imagine, a large number of teenage boys locked in their bedrooms “having a laugh”. Hitherto I’ve tended, in my turn, to laugh them off, joking that a death threat by email doesn’t count: it needs a letter sent to my home address containing one of my loved ones’ ears to be taken seriously.

However, after the murders of the Charlie Hebdo cartoonists Cabu, Wolinski, Tignous and the paper’s editor-in-chief, Stéphane Charbonnier – who signed himself “Charb” – there’s a terrible temptation to stop laughing. Although that, I believe, would be a fundamental error.

Laughter, it needs to be shouted, is one of the things humans do best, mostly because it makes us feel better. I’ve been convinced for years that laughter is a hardwired evolutionary survival mechanism that helps humans navigate our way through life without going mad with existentialist terror. That’s why we laugh at all those terrifying things like death, sex, other people and the disgusting stuff that pours out of our bodies on a daily basis.

Martin Rowson: Despots cannot bear mockery

Moreover, we’re very, very good at laughing at those who place themselves above us, either as our leaders or intending to impose their beliefs to make everyone else exactly like them. That’s the basis of the craft I shared with my murdered colleagues in Paris. This universal capacity to use mockery as a form of social control is one of the main things that makes us human. Crucially, it’s also in defiance of the primary need of the powerful to be taken seriously, often against all the external evidence of their innate absurdity.

In fact I suspect that throughout history that’s how political and religious power gained its original heft, by terrorising everyone else to suppress their giggles at the endless cavalcade of priest-kings, emperors, thrones, courts, burning bushes, virgin births, hidden imams, flying horses and all the rest of it.

But even then there appears to be something exquisitely intolerable to the serious mind about mockery when it is visual. Largely this is due to the way the visual is consumed: rather than nibbling your way through text, however incendiary, a cartoon floods the eyes and gets swallowed whole – and often makes the recipient choke. Worse, cartoons should be seen more as a kind of sympathetic magic than anything else: we steal our subjects’ souls by recreating them through caricature and then mock them in narratives of our own devising. Worst of all, we then pretend that it’s all just a good-natured laugh: it is a laugh, but it’s also assassination without the blood.

“Without the blood” is the key phrase. In a weirdly indefinable but obvious way, satirists can only really function when it’s hideously clear that the objects of their mockery are much more powerful and have a far deadlier armoury than the satirists, as was demonstrated with such foul clarity in Paris yesterday.

Aftermath of attack on Charlie Hebdo magazine office in Paris – video Guardian

But is that entirely true? Almost nine years ago, when the Danish cartoons storm erupted, I argued publicly that I thought Jyllands-Posten had been wrong to commission cartoons of the prophet Muhammad, as I suspected they were just another salvo in the paper’s decades-long campaign against immigrants, many of them Muslims, most poor and powerless, and some of them cleaning Jyllands-Posten’s toilets

I was roundly condemned by many for betraying free speech. Maybe I was, but claiming that the greatest freedom is to say whatever you want about anyone, whomsoever you choose, is ultimately as ludicrous as demanding that freedom from being offended – from being upset, in other words – trumps every other human right. On that occasion the blood flowed in gallons, though mostly unnoticed or unreported gallons as they gushed exclusively from more than 100 Muslims, shot dead by Muslim police or soldiers on the streets of Muslim countries in rioting fomented by Muslim clerics eager to flex their political muscles.

This time it is cartoonists’ blood that’s been shed. Yet however much their murderers may identify themselves as victims of mockery, they have clearly also identified themselves as on the side of power, electing to act as agents avenging the hurt feelings of the most Powerful Being in the Universe. Don’t forget that demanding either respect or silence from everyone else is one of the most common abuses of power going.

Charlie Hebdo is planning to continue printing its magazine next week. As chairman of the British Cartoonists’ Association, I am calling on my fellow cartoonists to join me in donating a free drawing. We should support them materially. We must also make a statement.

Don’t fool yourselves that this is about Islam. It was the Islamists’ secularist enemy Bashar al-Assad who got his thugs to break the fingers of the Syrian cartoonist Ali Ferzat four years ago. The Palestinian cartoonist Naji al-Ali was murdered in London in 1987 by a student who claims to have been a double agent for Mossad and the PLO. The British cartoonists’ names in the Gestapo death list were just another manifestation of how hateful laughter is to despots throughout history. Which is why, now more than ever, we mustn’t stop laughing this latest bunch of murderous clowns to scorn.