Contributions of the Philosophy of Chemistry and Mesology to the Conceptual Analysis of Complexity

Starting with Wittgenstein’s approach to “family resemblances”, the first part of this paper sets out to clarify the notions of complexity and complex systems. This will lead me to take a closer look at modeling practices at different scales. Then, I propose to show that the sensitivity to the surroundings – which plays a constitutive part in what a complex system can do, the temporary stabilization of an order and structure, the methodological and pragmatic pluralism that articulates numerous methods, models, approximations and scientific representations with diverse instrumentations – gain in clarity and are better understood when we refer to chemical practices and mesology. In the second part of the paper, I will show that, for a huge number of reasons linked to its objects, to the co-dependence of chemical bodies and transformations which is in turn dependent on associated media, and to the methodological pluralism of chemists, the philosophy of chemistry can provide some very interesting elements for approaching the study of complexity and complex systems. In such a framework mereology is not just about wholes and parts, and the concepts of affordances, transductive relations and associated media can provide a distance from the metaphysics of individuals, that can be problematic when the question of complexity comes into play. More briefly, I will point out in the third and last part of this paper, how mesology, by extending the link of mutual dependence between living beings and associated media, offers in turn valuable conceptual tools, such as mediance, concrescence, Umwelt, trajection and trajective chains, for thinking about complexity and complex systems.