You can trust death. All the “alternative facts” and “fake news”, all the dismissals of “objectivity” as “another form of subjectivity”, the claims that truth is relative… these all stop at the hard, objective, undisputable, undeniable fact of death.

So it seemed until last Wednesday, when a journalist officially pronounced murdered on Tuesday was in fact alive and well and that his murder had been staged.

Not just any journalist, but Arkady Babchenko, one of Russia’s most fearless war correspondents and Putin critics, who made his name at a newspaper, Novaya Gazeta, where journalists are murdered with sickening regularity. News of his death was followed by mass outpourings of grief. Boris Johnson even gave a speech. And then the next day he was paraded alive on television.

Babchenko, who has fled Russia for Ukraine, claimed his fake death was necessary: the Ukrainian secret service, the SBU, had got wind of a Russian operation to kill him and the only way to catch the organisers was to imitate the murder. No one doubts the danger he is in. It’s too early to ascertain if the SBU acted effectively. But after outpourings of joy that he was still alive, many wondered, would there be a cost? Had it raised or demeaned the credibility of Ukrainian officials? Would it mean that information about other murdered journalists would be treated as “fake news”? Does it further undermine the sense of objective reality, which the Kremlin works so assiduously to do in undermining Ukraine?

It’s not as if reality has been having a good time of it. Last week was typical. The Evening Standard, it was claimed, has offered favourable coverage to companies in return for money: the pieces would be so subtle, it was alleged, they would blur the line between advertising and reporting. The newspaper has denied the claims. Meanwhile, an English aristocrat television pundit (who commented on the royal wedding for US TV) turned out to be a New Yorker in a tweed jacket and fake accent.

Pillar by pillar, the architecture of shared reality has been knocked down. It used to be believed that having lots of TV channels would lead to better debate and more mutual understanding. Instead, in the US especially, it has led to a reality so fractured that Fox and CNN viewers now live in worlds so polarised it’s doubtful they are still living in the same reality.

The internet, which was meant to deliver us from the hegemony of television, has turned out to be even easier to manipulate: full of fake accounts who purport to be one person but turn out to be another, run by the Kremlin or Bell Pottinger, attention captured by “trending topics” created by bots “manufacturing consensus”.

If one goes to the farther reaches of the internet, to 4Chan messaging boards or Discord channels, you will find digital activists involved in sharing GCHQ and KGB manuals on information manipulation, instructions on how to “shape reality”. Anyone, not just the SBU, can play at being a little media Machiavelli now. And in a sense we have all become mini spin doctors of ourselves. Every time we go on Facebook and show off our photos, share or dislike, we become digital influencers. Although, as it’s become clear, the sense of self-empowerment Facebook gives us is just a way to get us to reveal more about ourselves and thus be made more pliable by larger forces to whom Facebook sells our data.

But surely there are some things we can put our faith in? The most trusted people in societies save lives: medical and emergency professionals, soldiers. Since the Babchenko case broke, some in Ukraine have brought out this aspect. Maxim Eristavi, a critic of both Putin and Ukrainian authorities, a journalist and one of Ukraine’s leading LGBT campaigners, was positive about the operation: this was the first time the security services had shown themselves to be on the side of journalists.

The Ukrainian writer Andrey Kurkov said it felt like the security services were on the side of their own people for the first time. Eristavi and Kurkov were looking at trust as something generated by the sense of people looking out for you. Kurkov is perhaps best known as the author of Death and the Penguin, a satire about post-Soviet Ukraine in which an obituarist finds that the columns he prepares for the possible death of their subjects are a murder hitlist for a mafia. I mention this because when it comes to dealing with a world where reality has broken down, Ukrainians have experience in what really matters.

But even faith in those who risk their lives for others has taken a mauling. The White Helmets, the first responders in Syria who pull people from the rubble after the barrel bombs, have become the target of online disinformation, which has found a receptive audience. Much of it is pathetically easy to catch out: pictures of a girl being rescued by three different people is taken as evidence that she’s an actress. She’s not, children get passed from one rescuer to the next in any operation. But if you live in a world where you’re so aware that everything can be manipulated it’s easier to doubt than risk being taken for a ride. Triumphant, gloating cynicism is a safe space to retreat to.

So are we doomed to endless manipulations and snide asides? If you have attended one of those awful corporate trust-building exercises, you know how they create bonds by forcing people to collaborate on achieving something.

Within minutes of the news of Babchenko’s death, usually rival teams of investigative journalists had started an investigation, knowing the authorities are never to be trusted. Within hours, the streets were crawling with people gathering video from shop security cameras, cross-checking police data, talking to witnesses, with each piece of the puzzle co-ordinated live. Money was raised to support his family. Other investigative journalists flew in from Moscow. Perhaps such collaborative archipelagoes fostering truth are one thing to hold on to.

A more extreme gesture is self-sacrifice: if you’re ready to put your life on the line, it means you mean it. In northern Russia, the Ukrainian film director Oleg Sentsov, who opposed the Russian takeover of Crimea and is facing 20 years in jail on fact-free charges of “terrorism”, has gone on hunger strike to draw attention to the 64 Ukrainian political prisoners in Russia. We can all build trust by helping to rescue those lives.

• Peter Pomerantsev is the author of Nothing Is True and Everything Is Possible and senior fellow at the Arena programme at the London School of Economics