Post-Normal Science is a concept developed by Silvio Funtowicz and Jerome Ravetz, attempting to characterise a methodology of inquiry that is appropriate for cases where "facts are uncertain, values in dispute, stakes high and decisions urgent" (Funtowicz and Ravetz, 1991). It is primarily applied in the context of long-term issues where there is less available information than is desired by stakeholders.
According to its advocates, "post-normal science" is simply an extension of situations routinely faced by experts such as surgeons or senior engineers on unusual projects, where the decisions being made are of great importance but where not all the factors are necessarily knowable. Although their work is based on science, such individuals must always cope with uncertainties, and their mistakes can be costly or lethal.
Because of this, advocates of post-normal science suggest that there must be an "extended peer community" consisting of all those affected by an issue who are prepared to enter into dialogue on it. These parties bring their "extended facts", that will include local knowledge and materials not originally intended for publication, such as leaked official information. A political case exists for this extension of the franchise of science, but Funtowicz and Ravetz also argue that this extension is necessary for assuring the quality of the process and of the product.