On March 28th, Toby Ord spoke at the Oxford Literary Festival about the forthcoming book he contributed to: Is The Planet Full? Toby’s chapter, ‘Overpopulation or Underpopulation?’ raises a number of philosophical questions concerning how we should think about population, involving ethics and technology. He shows that as well as downsides, there are several major upsides of increased population and it is not obvious whether the ideal population level is higher or lower than the present level.