ABSTRACT
An explanatory model provides a framework from which one can explore the receptive context within which professionals and patients conduct their conversations during consultations. Its propositions create boundaries within which these conversations can take place and also, in so doing, create constraints. The nature of an explanatory model betrays a predilection for a certain type of knowledge – the collection of 'facts' which populate one's explanatory model. Medicine's conventional explanatory model is based on the scientific tradition. The chapter proposes that the basis of the world-view underpinning that model is scientific positivism. Scientific positivism is central to the ontological view held, usually more tacitly than explicitly, by those who support medicine's conventional explanatory model. Evidence-based medicine depicts a world that is rational and objective, and which can be measured empirically. In 1992 the NHS Management Executive published a document which for the first time linked advice about commissioning services at the level of regional health authorities to contemporary clinical evidence.
