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?

Splitting the truth: the philosopher that physics forgot

In the early 20th century, Newtonian physics was upended by experiments that revealed a bizarre subatomic universe riddled with peculiarities and inconsistencies. Why do photons and electrons behave as both particles and waves? Why should the act of observation affect the behaviour of physical systems? More than just a puzzle for scientists to sort out, this quantum strangeness had unsettling implications for our understanding of reality, including the very concept of truth.

The German mathematician and philosopher Grete Hermann offered some intriguing and original answers to these puzzles. In a quantum universe, she argued, the notion of absolute truth must be abandoned in favour of a fragmented view – one in which the way we measure the world affects the slice of it that we can see. She referred to this idea as the ‘splitting of truth’, and believed it extended far beyond the laboratory walls and into everyday life. With a striking visual style inspired by the modern art of Hermann’s era, this Aeon Original video explores one of Hermann’s profound but undervalued contributions to quantum theory – as well as her own split life as an anti-Nazi activist, social justice reformer and educator.

What you can tell about a person from the junk they leave behind

The Canadian filmmaker Charlie Tyrell delves into his late father’s belongings in an effort to better understand the man’s inscrutable inner life, including his somewhat cold and distant demeanour towards his three children. Finding no answers in those titular, poorly hidden VHS tapes, Tyrell tugs at the roots of his family tree, uncovering an intergenerational cycle of abuse that makes him reconsider his complicated relationship with his father. Crafted with humour and heart, Tyrell’s inventive and deeply personal collage of animations, archival footage and audio recordings was a hit at the Sundance Film Festival and the Toronto International Film Festival in 2018, among others.

Five miles of fake flowers, cat cushions and muzak: enter the world’s largest market

The Yiwu International Trade City in China is the world’s largest wholesale market for consumer goods, stretching some five miles and featuring roughly 75,000 vendors. The Chinese-American filmmaker Jessica Kingdon’s observational documentary Commodity City employs static shots of everyday scenes from the market – mostly without dialogue – to convey the seemingly endless stretches of vendor booths that specialise in everything from cat pillows to Santa figurines. Through these vignettes, Kingdon captures the incongruous interplay of boredom and commerce, vastness and claustrophobia that characterises this otherworldly space, offering a hypnotic anthropologic exploration of consumer culture and capitalism.

People have been trying to talk with apes for nearly a century. How far have we got?

Since the early 20th century, a number of curious (and sometimes ethically dubious) psychological studies have tried to figure out if we can communicate with great apes using language. In the 1970s, the answer was reported to be an unequivocal ‘yes’ after Koko, a female western lowland gorilla, learned to sign at her handler, a graduate student at Stanford University, using a modified version of American Sign Language. But more recent critiques of the Koko studies (and others) dispute the idea that great apes have had truly meaningful two-way language communication with humans. This video from NPR’s Skunk Bear offers a brief survey of the history of ape-human communication research, suggesting that ‘Can we talk with them?’ might be the wrong question to ask.