A topological approach to the problem of emergence in complex systems
  Emergent patterns in complex systems are related to many intriguing phenomena in modern science and philosophy. Several conceptions such as weak, strong and robust emergence have been proposed to emphasize different epistemological and ontological aspects of the problem. One of the most important concerns is whether emergence is an intrinsic property of the reality we observe, or it is rather a consequence of epistemological limitations. To elucidate this question, we propose a novel approximation through constructive topology, a framework that allow us to map the space of observed objects (ontology) with the knowledge subject conceptual apparatus (epistemology). Focusing in a particular type of emergent processes, namely those accessible through experiments and from which we have still no clue on the mechanistic processes yielding its formation, we analyse how a knowledge subject would build a conceptual explanatory framework. Working on these systems, we identify concept disjunction as a critical logical operation needed to identify the constraints of the system. Next, focusing on a three-bits synthetic system, we show how the number and scope of the constraints hinder the development of such scheme. Interestingly, we observe that our framework is unable to identify global constraints, clearly linking the epistemological limits of the framework with an ontological feature of the system. This allows us to propose a definition of emergence strength which we make compatible with the scientific method through the active intervention of the observer on the system. We think that this definition reconciles previous attempts to classify emergent processes, at least for the specific kind we discuss here. The paper finishes discussing the relevance of global constraints in biological systems, understood as a downward causal influence exerted by natural selection. 
Alberto Pascual-Garc\'ia
physics.soc-ph physics.data-an q-bio.OT