How quantum superposition could unravel the ‘grandfather paradox’

The ‘grandfather paradox’ has long been one of the most popular thought experiments in physics: you travel back in time and murder your grandfather before he’s ever born. If you’ve killed your grandfather, you’ve prevented your own existence, but if you never existed, how could you have committed the murder in the first place? Some physicists have avoided the question by arguing that backwards time travel simply isn’t consistent with the laws of physics, or by asserting a ‘many worlds’ interpretation of the Universe. But could the concept of quantum superposition remove what seems so paradoxical from this tale of time travel and murder once and for all?

How British police put 16 men in the dock for consensual sadomasochism

In the late 1980s in the UK, Roland Jaggard was part of a loose-knit group of men who engaged in, and occasionally videotaped, consensual sadomasochistic same-sex acts. While Jaggard acknowledged that aspects of his sex life were ‘not to everyone’s taste’, he never imagined that it would cost him his job, unleash a tabloid-fuelled public outcry, and land him and 15 other men in prison. The UK filmmaker Charlie Lyne’s vertical video Lasting Marks delves into the history and complicated legacy of the UK-wide police investigation, codenamed ‘Operation Spanner’, that cost more than £2.5 million and saw around 100 men questioned over their sex lives. In court, the prosecution argued that consent wasn’t a defence for causing bodily harm, creating a precedent that still holds in UK law today. Composed exclusively of photocopied documents, Jaggard’s voice and a sparse score, the film skilfully explores the evolving and uncertain boundaries between public and private life, what’s socially acceptable and what’s taboo, and how the state tries to police sexual behaviours.

The 94-year-old Holocaust survivor who makes every Purim costume contest count

‘It’s important to have something that makes you laugh a little bit.’

At 94 years old, Anny Junek has a streak going: she’s the three-time winner of the Purim costume contest at her retirement home in Rehovot in Israel. As the Jewish holiday approaches again, she’s angling for a fourth win. How will she capture the prize? Don’t ask, it’s a surprise! As a young woman, Junek survived the Bergen-Belsen concentration camp, but lost her parents to the gas chambers of Auschwitz. After the trials and tragedies of her early years, Junek’s perseverance and humour have carried her through a life that included raising a family in Mexico before retiring to Israel. Now her indomitable spirit and sense of what makes for a good show have her hatching a new plan for Purim in this charming film by the US-born, Israel-based director Tamir Elterman.

Come ice-fishing in the deep Canadian winter with an all-Indigenous, all-female crew

‘Indigenous labour is never just work. It’s cultural practice, our Indigenous knowledge. It’s how we are in the world,’ says the Cree filmmaker Alexandra Lazarowich, discussing her inspiration for her latest short documentary, Lake. Produced as part of the Five Feminist Minutes initiative of the National Film Board of Canada (NFB), this observational short by an all-female, all-Indigenous crew follows Métis women on an ice-fishing outing at Lesser Slave Lake in central Alberta. The sweep of the landscape, the crunch of ice and snow, and the whipping wind evoke the sublime vastness and frigid temperatures of the deep Canadian winter. Within this frozen world, the women are masters of their craft, punching a hole in the ice, dropping their nets through, and eventually pulling their catch to the surface. A richly crafted testament to Indigenous expertise drawing on the style of verité documentaries of the 1960s and ’70s, the film is also an understated acknowledgement of the challenges that Canada’s Aboriginal peoples face in accessing fishing rights – rights that have long been subject to government encroachment.

Your body is scanned, destroyed, then reproduced. Do ‘you’ live on the copy?

For centuries, philosophers – and more recently, science-fiction writers – have been concocting riffs and variations on a particular thought experiment: if every bit of your body could be perfectly scanned and replicated, in what ways would the replica still be ‘you’? In this interview from the PBS series Closer to Truth, Andy Clark, a professor of philosophy at the University of Edinburgh, dissects a version of this experiment posed by the US philosopher Daniel Dennett, in which a body is scanned, destroyed, and replicated in a distant place. While science hasn’t yet brought us close to putting Dennett’s conundrum to the test, we can still grapple with the intriguing and perhaps troubling metaphysical questions it raises, questions that might become even more material as we careen further into the information age, including: would ‘you’ be dead, or would your sense of self perpetuate in the copy? And, if you were recreated several times, where exactly might you expect to find your embodied sense of self?