The virtual reality (VR) industry is currently in its infancy, but in just a few decades it’s possible that virtual environments will be nearly indistinguishable from reality. Along with transforming everyday life, a VR revolution could fundamentally change how we understand and define what is real. In this instalment of Aeon’s In Sight series, the renowned Australian philosopher and cognitive scientist David Chalmers considers how VR is reframing and shedding new light on some of philosophy’s most enduring questions about cognition, epistemology and the nature of reality.