Fields, Spaces and States

Models allow us to both understand and predict phenomena. In the case of models used in environmental health risk assessment, the phenomena are those of the relationship between sources of risk (e.g. a factory), the state of the environment (e.g. the state of the atmosphere), and various states of health. The predictions tell us what will happen to both the state of the environment and the state of health under well-described circumstances such as an experiment or introduction of an environmental policy. If models also embody understanding, they tell us why these events happen in the order in which they do, based on an understanding of the principles governing the phenomenon. Environmental models are most successful when they embody both prediction and understanding, and so this book focuses on both aspects of a model.