Chapter 1

Public health is particularly challenging because it involves collective action affecting collectively shared conditions.1 Collectively shared conditions include resources such as clean air and water, food and land, public services, public space or threats to these shared resources, such as a contagious disease, spreading pollution, overutilization of public services or overcrowding. All of these are at least partially shared conditions. How we drive, whether or not we smoke or pollute affects the space and potentially the health of others as well as ourselves. Whether or not we protect against infection affects others as well as our own chance of staying healthy. These are just a few examples of how the action of one individual affects the health conditions of others, a situation that can lead to conflict between individuals and collectives. These collectives are, on the one hand, aggregates of different individuals who take independent action, often to change their own individual conditions. On the other hand, individual actions often change collectively shared conditions.