Physics and Complexity

It is argued here that the notion of complexity, fashionable as it is in many considerations about contemporary science, is of little relevance for physics, except perhaps in some restricted areas of statistical physics. The point is that theoretical physics, due to its intrinsic mathematical formalisation, may in general, as will be shown through several examples, escape the vexed problem of treating the reciprocal couplings between different levels of analysis or heterogeneous parts of a system — which is taken here as a minimal characterisation of complexity. However, it must be granted that physics, if not a theoretical science of the complex, is indeed a complex science when considered from the point of view of practice. But this is hardly a deep statement, as it only shows that if it is certainly worthwhile to recognise complexity as a feature of scientific activity, the word here may hardly go beyond its meaning in ordinary parlance and cannot pretend to a serious scientific or philosophical content.