It's clear that human social morality has gone through significant changes in the past. But why? What caused these changes? In this episode, I chat to Jeroen Hopster from the University of Utrecht about this topic. We focus, in particular, on a recent paper that Jeroen co-authored with a number of colleagues about four historical episodes of moral change and what we can learn from them. That paper, from which I take the title of this podcast, was called 'Pistols, Pills, Pork and Ploughs' and, as you might imagine, looks at how specific technologies (pistols, pills, pork and ploughs) have played a key role in catalysing moral change.