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.