Identified in the writings of Max Weber, and more recently resurrected by the British sociologist Frank Parkin, the concept emerged as an alternative to Marxist theories of inequality and of how the latter is generated, maintained, and transformed (see Parkin's Marxism and Class Theory, 1979). Weber saw closure as being one of the means by which commercial and property classes moved along the continuum of legitimating and reproducing their life-chances in the direction of social class formation. Later exponents of this view saw closure as the basis of all inequality, be it that of material reward, status honour including ethnicity, caste, and even the nomenklatura system of communist regimes.
Closure functions through the twin mechanisms of exclusion and inclusion and can be founded upon individualistic or collective criteria. It is based on the power of one group to deny access to reward, or positive life-chances, to another group on the basis of criteria which the former seek to justify. The selection of these criteria of exclusion and inclusion—be they educational credentials, party membership, skin colour, religious identity, property, social origins, manners and style of life, or region—and their imposition, contribute to explaining the boundaries of inequality and the strategies of usurpation on the part of the excluded, as much as the patterns of domination and the legitimizing ideologies for inequality. Processes of social closure involve marginalization (or exclusion), on the one hand, and incorporation (inclusion) on the other.
Since closure is about mobilizing power to exclude others from privileges or rewards, students of the process tend to assume that power is itself an attribute of closure, and rarely investigate the sources of that power. Thus, an educational elite is assumed to have the power to exclude those without the relevant credentials, if their exclusionary strategies hold. Often, however, there are competing modes of closure which conflict with each other. Furthermore, elites defined by one criterion (say, education) may not always seek the obvious (in this case educational) means to achieve closure—attempting to exclude people, instead, on other grounds (such as those of gender or ethnicity). One other problem with closure theories stems from the uneven distribution of reward within a group practising closure, as for example in the case of the communist nomenklatura, where rewards to those in the lower reaches were questionable to say the least. The best overall assessment of closure theory is Raymond Murphy's Social Closure: The Theory of Monopolization and Exclusion (1988).