Explaining the past: abductive and Bayesian reasoning

Abductive reasoning is the central form of explanation in environmental reconstruction. This paper outlines the nature of the abductive method restating it in Bayesian terms, ie, in terms of a priori belief based on context and the relations between multiple proxies. A key role within this working method is played by evidence and, in particular, proxies of the past in the explanatory framework. Proxies, whether singularly or as groups, are interpreted within the context of the event, and the derived hypothesis, for which they have evidential claim. They are not considered as independent entities but rather as inter-related pieces of information concerning the likelihood of specific events. The degree of belief in an individual proxy is based on the interplay between the belief in the hypothesis before the proxy is considered and the relations and belief in the cluster of proxies of which the individual proxy is usually a part.