The Kac Ring or the Art of Making Idealisations

In 1959, mathematician Mark Kac introduced a model, called the Kac ring, in order to elucidate the classical solution of Boltzmann to the problem of macroscopic irreversibility. However, the model is far from being a realistic representation of something. How can it be of any help here? In philosophy of science, it is often argued that models can provide explanations of the phenomenon they are said to approximate, in virtue of the truth they contain, and in spite of the idealisations they are made of. On this view, idealisations are not supposed to contribute to any explaining, and should not affect the global representational function of the model. But the Kac ring is a toy model that is only made of idealisations, and is still used trustworthily to understand the treatment of irreversible phenomena in statistical mechanics. In the paper, my aim is to argue that each idealisation ingeniously designed by the mathematician maintains the representational function of the Kac ring with the general properties of macroscopic irreversibility under scrutiny. Such an active role of idealisations in the representing has so far been overlooked and reflects the art of modelling

Transforming poverty-related policy with intersectionality

Despite progress toward poverty alleviation, policy making still lags in thinking about how individuals experience poverty as overlapping sources of disadvantage. Using the lens of intersectionality, this article identifies the gaps that arise from a conventional focus on isolated facets of poverty. Insights generated from an analysis of extant scholarship are used to develop a road map to help policy makers develop programs that address the complex experience of poverty and promote transformative solutions