Robustness as Organized Heterogeneity

Robustness, the property by which living systems maintain a function despite external and internal perturbations, is currently one of the most powerful cross-disciplinary concepts relating both biological and artificial systems on the basis of their common organisational principles. In this paper we argue that robustness can be also considered an emergent property that plays a pivotal role in fostering the integration of functional levels in the organismal system. This perspective widens the concept of biological regulation in order to better account for the explanatory relevance of robustness in biomedical sciences. Paradigmatic for this discussion is the biology of cancer. The investigation of the unorganized heterogeneity exhibited by cancer cells offers, in fact, an insight into the conditions for the organized dynamic functional heterogeneity that underlies the robustness of healthy organisms. In its integrative capacity, robustness can be therefore better characterized in the framework of a relational ontology of levels, whose dynamics of co-determination involves different types of dynamic principles and ensures the integration of functional macrostates at different scales.