The question of whether any of us can truly be held responsible for what we do is an issue that occupied the ancient Greeks and continues to entertain our leading thinkers. Whether we can be held responsible for our health, or lack thereof, has additional layers of complexity because of the way in which what we do over time impacts our health. Those of us who have ever self-deceptively wondered about the apparent shrinking of our belt or at the fact (...) that the stairs seem to have multiplied are familiar with the idea that our health can change gradually over time as a result of successive choices that we have made. While there are one-off behaviours that can have an impact on health, for example, a single exposure to a very high level of radiation, in general, ill health develops over time, within an environment and complex set of interactions with other people. The implications of that complexity are central to this issue’s Feature Article by Brown and Savulescu.1 They note that there is debate over whether responsibility should play a role in the allocation of healthcare, and, rather than taking a view on that issue, make a number of suggestions about how the concept of responsibility used in healthcare can be enriched by attending to the complex relationship between behaviour and health. …. (shrink)