Nicholas Christakis thinks that pharmaceutical drugs are terrific—yet they work only some of the time. Alastair Santhouse thinks that psychiatry is the noblest branch of medicine—yet it is characterised by dullness of thought and practice. Ike Iheanacho thinks predictive models have provided countless advances in the understanding of disease and treatment—yet they are too easily believed.

All three offer alternative ways of looking at familiar things. Christakis’s point is that doctors and patients have different understandings of what it means to say that a drug “works” (doi:10.1136/bmj.a2281). Against the patient’s standard most drugs don’t work. …