Last week, David Cameron reiterated his commitment to the Big Society. Like another UK prime minister, Tony Blair, who more than a decade ago talked of stakeholding, Mr Cameron is genuinely trying to articulate a big idea. Like Mr Blair, he runs the risk that his big idea becomes a platitude, dying amid deserved derision.

Both Mr Cameron and Mr Blair perceived that the major part of modern social political and economic life is conducted through intermediate institutions, groups with an identity stronger than mere gatherings of individuals but which are not institutions of the state. Such groups are many kinds: the most important are companies, but they include clubs and charities, pressure groups and partnerships, mums’ networks and mutuals. Through these agencies, we achieve the combination of plurality and cohesion that makes the complexities of modern society manageable.

If this seems obvious, it is an observation that contradicts the dominant political and economic models of our time. Such political models are commonly based on some sort of social contract of the kind described by John Rawls and similar philosophers, translated into structures that stress individual rights and give little role to feelings of group solidarity. The analogous economic models are those in which atomistic economic agents contract with each other to achieve harmonious equilibrium.