This chapter initially explains how dependencies are established when at least a part of an infrastructure system requires the provision of the service to function. Although the focus is on functional dependencies, this chapter also explores physical and conditional dependencies. Resilience metrics presented in previous chapters are broadened in order to represent the effect of dependencies on resilience levels. Dependencies established within an infrastructure system are also explained. The concept of buffer as a local storage of the resources related to the depending service is defined as part of these expanded metrics, and then it is exemplified by examining a practical application of such buffers: power plants for information and communication network (ICN) sites. After introducing the main concepts and ideas related to dependencies, this chapter takes a broader view by discussing interdependencies when those are established both directly and indirectly. The study of interdependencies for electric power grids and ICN also explores the relationship with other infrastructures, such as transportation networks and water distribution systems, and with community social systems.

The Introduction outlines the book’s conceptual foundations, starting with a theory of political economy as constitution that builds on both economic and political thought to conceptualise the relationships between the economic and the political bodies. Accordingly, the body politic is an orderly arrangement of individuals and groups fitting a collective condition, or purpose, which would at a minimum include the persistence of the political body itself. Similarly, the economic body is an orderly arrangement of individuals and groups fitting a systemic condition for material sustenance and welfare, which would at a minimum ensure resilience of an organised economic sphere. The theory of political economy shows shifts between a focus on dispositional activities (such as allocation of capabilities or resources) and a focus on material and social interdependencies. This dynamic often makes it difficult to identify the underlying unity of political economy. Reductionist theoretical developments, both in economic and in political theory, have failed to address the embeddedness and mutual shaping of dispositions and structures at multiple levels of aggregation in the economy and the polity. The Introduction sketches a new theoretical framework that avoids both types of reductionism by highlighting the close integration between human dispositions and socio-economic interdependencies.

The evolution of CST is studied in this chapter, in relation to the three distinct main matters denoted by the ambiguous term “globalization”: (1) the increasing interconnections and interactions between people all over the world and the resultant interdependencies that reinforce other interdependencies such as exhaustion of natural resources, transfer of resources, money, means of destruction, people, vulnerability to pollution and environmental degradation, and so on; (2) proposals to respond to all that (and to “dangerous anthropogenic global warming”) by establishing global law and institutions of governance; (3) proposals to facilitate migration from poorer countries to richer ones for the sake of a better life for the migrants (and their relatives or other dependents). Neither CST nor the rest of Catholic moral doctrine has doubted that states and peoples have a responsibility to respect other states and peoples and the common good of human persons worldwide; or that individuals and groups have, in dire necessity, rights to seek and find refuge in nearby safe states for at least the duration of that danger and necessity. But beyond these basics, there have been developments, in various directions. And this chapter traces some main developments over the past 125 years.

The common good (bonum commune) has, since antiquity, referred to the aim of social and political association, and was particularly prominent in medieval Christian political theology. Since St. John XXIII’s 1961 encyclical letter, Mater et magistra, ecclesiastical statements about social teaching have employed a formulation of the common good, usually in the version that appeared in the Second Vatican Council’s 1965 Pastoral Constitution for the Church in the Modern World, Gaudium et spes, as “the sum of those conditions of social life that allow social groups and their individual members relatively thorough and ready access to their own fulfillment.” This chapter discusses the origins and development of this formulation as well as the ways that it has been used in subsequent Catholic Social Teaching. While it has sometimes been interpreted as an “instrumental” account of the common good, the sources and uses of the notion suggest that it is the particularly modern political component of a fuller notion of the common good continuous with the tradition. In particular, the recent formulation is concerned to limit the power of the modern state and protect the dignity of the human person in the challenging conditions of political modernity.