Nick Bostrom: ‘We are like small children playing with a bomb’

Sentient machines are a greater threat to humanity than climate change, according to Oxford philosopher Nick Bostrom

You'll find the Future of Humanity Institute down a medieval backstreet in the centre of Oxford. It is beside St Ebbe's church, which has stood on this site since 1005, and above a Pure Gym, which opened in April. The institute, a research faculty of Oxford University, was established a decade ago to ask the very biggest questions on our behalf. Notably: what exactly are the "existential risks" that threaten the future of our species; how do we measure them; and what can we do to prevent them? Or to put it another way: in a world of multiple fears, what precisely should we be most terrified of?

When I arrive to meet the director of the institute, Professor Nick Bostrom, a bed is being delivered to the second-floor office. Existential risk is a round-the-clock kind of operation; it sleeps fitfully, if at all.