I problemi delle societa' multi-etniche

Adesso Robert Putnam ha scopertoche la cosiddetta società multiculturaleche con l’aumento delle differenzediminuisce la disponibilità delle persone a
impegnarsi per il bene comune.
Camillo Langone (Il Foglio 14 agosto 2007)

Robert David Putnam (born 1941 in Rochester, New York) is a political scientist and professor at Harvard University. In 2000, he published Bowling Alone: The Collapse and Revival of American Community, a book-length expansion of the original argument, adding new evidence and answering many of his critics. Though he measured the decline of social capital with data of many varieties, his most striking point was that many traditional civic, social and fraternal organization -- typified by bowling leagues -- had undergone a massive decline in membership while the number of people bowling increased drastically.

Making Democracy Work: Civic Traditions in Modern Italy (with Robert Leonardi and Raffaella Nannetti, 1993)

Putnam makes a distinction between two kinds of social capital: bonding capital and bridging capital. Bonding occurs when you are socializing with people who are like you: same age, same race, same religion, and so on. But in order to create peaceful societies in a diverse multi-ethnic country, one needs to have a second kind of social capital: bridging. Bridging is what you do when you make friends with people who are not like you, like supporters from another football team. Putnam argues that those two kinds of social capital, bonding and bridging, do strengthen each other. Consequently, with the decline of the bonding capital mentioned above inevitably comes the decline of the bridging capital leading to greater ethnic tensions.

BETTER TOGETHER: Restoring the American Communityby Robert D. Putnam and Lewis M. Feldsteinwith Don Cohen(Simon & Schuster; September 10, 2003)

In recent years Professor Putnam has been engaged in a comprehensive study of the relationship between trust within communities and their ethnic diversity. His conclusion based on over 40 cases within the United States is that, other things being equal, more diversity in a community can mean less trust both between and within ethnic groups.

Putnam has not yet published this work. In 2006, Putnam was quoted in the Financial Times as saying he had delayed publishing this research until he could "develop proposals to compensate for the negative effects of diversity" (quote from John Lloyd of Financial Times)

http://en.wikipedia.org/wiki/Robert_Putnam