Alex Jadad and Laura O’Grady’s call for a debate on the definition of health has stimulated fascinating responses to both their editorial (doi:10.1136/bmj.a2900) and their blog (http://blogs.bmj.com/bmj/2008/12/10/alex-jadad-on-defining-health). I particularly like Richard Smith’s response to the blog, in which he suggests that health is “the capacity to do what matters most to you” (http://blogs.bmj.com/bmj/2009/01/05/richard-smith-can-poetry-define-health).

Two other responses appear in this week’s Letters. Peter Mansfield recalls the Peckham experiment in London in the 1930s and 1940s, which aimed to investigate the nature of health (doi:10.1136/bmj.b83). An expanded vision of health is unlikely to come from within medicine, he says. “Economic and …