[Medicine's scientific ideals--a setback for reduction. Different explanatory models valid at different levels]

Although the breakthrough of molecular biology has favoured reductionist perspectives, a countertrend has recently emerged which emphasises multidisciplinary approaches linking research efforts in different fields in what has become known by such terms as 'integrative biology.' Subscribing to this trend entails critical reflection on the epistemological status of different models and explanations in order to avoid the fallacy of misplaced concreteness (i.e., totalising views or ideals of science). One strategy is to articulate more clearly the scope and relationships of concepts and models vis-à-vis the phenomena or 'system(s)' they are intended to represent. Thus, models and explanations at different systemic levels should be seen as mutually complementary, a standpoint for which the article provides a metatheoretical rationale.