We're heading off into the unknown in this week's podcast, with a pair of writers who explore what drives our human experiment.
The writer Kim Stanley Robinson has been examining possible futures for humanity for 40 years in a series of novels that stretch from nuclear devastation through climate chaos to Mars and beyond. His latest novel, Aurora, pushes 500 years onwards with a story of a vast starship on a 200-year journey to Tau Ceti.
Robinson explains why he decided to write a generation starship novel and why he's happier pushing at the boundaries of fiction rather than the boundaries of science.
The psychologist Sheldon Solomon has, by contrast, been expanding the realm of science, putting an insight from ancient philosophy – that our lives are shaped by our awareness of our own mortality – on a sound experimental footing.
Solomon explains how he and his colleagues Jeff Greenberg and Tom Pyszczynski have been measuring the ways in which the fear of death alters our behaviour and how the stories we tell ourselves against that fear have forged history.