Some years ago, I happened to meet a survivalist and conspiracy theorist. He told me he had weapons stashed inside the walls of his house, was ready to use them in defence of “English” women and children, and believed that the BBC was covering up a vast Muslim paedophile ring. It seems uncontroversial to describe this as a “far right” belief system. But the event that first led him to abandon his faith in liberal democracy had nothing to do with the traditional concerns of the right: it was the Iraq war. The internet and Tommy Robinson did the rest. There is a well-known “horseshoe” theory of political sentiment, which suggests that as ideologies become more polarised along a left-right axis, so they become more alike on a liberal-authoritarian one. This was a useful prop for centrists of the mid-20th century, who sought to portray themselves as the first line of defence against the gulag. Today, things are far more complicated than these simple axes of left-right and liberal-authoritarian imply. The problem in the age of big tech, the climate crisis, Covid lockdowns, online influencers and collapsed trust in “mainstream” politics and media is that everybody has their suspicions that they are being lied to and manipulated – and they’re right. Where they disagree is on the identity of the liars and the purpose of the manipulation. The rhetoric of critique and liberation has become ubiquitous, no longer serving to distinguish left from right, truth from falsehood. Virtually everyone now wants to unmask the elites and decode their messaging in one way or another. For leftist critics such as Naomi Klein, who made their names in a simpler pre-Trump, pre-YouTube age, this provokes an identity crisis. The premise of Doppelganger is so unlikely as to be almost absurd: Naomi Klein has spent several years being mistaken for the feminist turned conspiracy theorist Naomi Wolf, and has chosen to write a book about this. Both Naomis are Jewish women, who rose to fame on the back of unexpected polemical blockbusters, No Logo and The Beauty Myth respectively. Klein offers plenty of examples of how the confusion manifests itself, especially online, and of how it has troubled her at various points in her life, particularly during the pandemic, when Wolf’s celebrity as a lockdown and vaccine sceptic soared. You may well wonder how such a faintly comical theme can be extended for 350 pages, and what it has to do with Klein’s usual preoccupations of combating corporate capitalism and climate crisis. It is certainly the most introspective and whimsical of Klein’s books to date, but it is also one of surprising insights, unexpected connections and great subtlety. The Klein/Wolf confusion is an entry point to consider wider forms of disorientation that afflict the left, in particular the loss of its monopoly (if it ever had one) over the language of political resistance, and how, in the process, that language has lost its grip on the world. Liberals and leftists like to reassure ourselves that we know when to trust the elites (on vaccine safety or climate science, say) and when not to (if corporate branding or billionaire-owned media are involved). But this same attitude of studied suspicion is at work among vaccine sceptics and online wellness communities, all of whom pride themselves on doing their “own research”. Marxists and sociologists have theories as to how money and power knit modern societies together – but so does Steve Bannon. Precisely how these differ is not always easy to specify, at least not in the kinds of online environments where so much public discourse now takes place. In some cases, Klein confesses, the very fact that conspiracy theorists were energised by something (such as the “lab leak” theory of Covid’s origins, or the privacy consequences of vaccine passports) led her and her comrades to dismiss it, when they had no real grounds to. The powers of “surveillance capital” and big pharma are real, yet hard to measure. Klein herself has drawn attention to those threats in her own work. But what if the online grifters and paranoid YouTubers speak to everyday anxieties about such things better than the left does? This is a worry that runs throughout Doppelganger. Has the left messed up? Does the right understand people better? Is Naomi Wolf even on “the right” anyway? In place of horseshoes, Klein prefers the metaphor of mirrors. Wolf is part of a “mirror world”, not so very different from ours, only with more histrionic language and online clout. Our digital avatars and personal brands are mirrors in which we each gaze narcissistically at ourselves, frequently mistaking image for reality, while the shared world burns around us. Doppelganger is really a story of political and psychic confusion. It also manages to encompass lengthy and fascinating reflections on the history of autism, the work of Philip Roth, and the comparability of the holocaust to colonial genocides in a way that chimes with the pervasive experience of “going down rabbit holes”. There’s a debate to be had about how liberals and leftists should relate to those drawn into the ecosystem of Wolf, Bannon and Trump. Doppelganger leans towards understanding more and condemning less, without ever romanticising those beholden to conspiracy theories. What is clear is that facts and critique alone will never be enough to lure anyone over to Klein’s side. The power of the “mirror world” is precisely that it already has facts and critiques galore. This is a book that offers scant optimism for the future, but if there is hope lingering here, it’s that collective self-reflection – through historical knowledge and organising – offers political resources that solitary self-reflection never will. True to form, Klein’s ultimate message is log off and get on to the streets. Doppelganger: A Trip Into the Mirror World by Naomi Klein is published by Allen Lane (£25). To support the Guardian and Observer order your copy at guardianbookshop.com. Delivery charges may apply.