ABSTRACT
Introduction Diversity is an issue that is attracting increasing attention in various spheres. The governments of more than 150 countries have ratified the Rio convention of 1992, which requires them to adopt economically costly policies aiming at the conservation of biological diversity (article 1 of the Rio convention). More recently, UNESCO has approved, in October 2005, the convention on the promotion and protection of diversity of cultural expressions. This convention has been invoked by the representatives of many countries in the negotiations at the World Trade Organization (WTO) in order to remove certain cultural goods from the scope of free trade agreements. In economics, there is a long-standing tradition of research in industrial organization that is concerned with product diversity and how it can be promoted by various forms of market competitions (Dixit and Stiglitz 1977) is a classical analysis of this topic. Diversity appears also to be an important aspect of the freedom of choice that individuals may have in different situations (Barberà, Bossert and Pattanaik 2004; Sugden 1998) according to surveys of the literature on the measurement of freedom of choice. More colloquially, one finds a significant concern in popular discussions about the diversity of opinions expressed in the media or in the political arena. But what is diversity? Would the killing of 500,000 flies of a specific species have the same impact on the reduction of biological diversity as the elimination of the last 6,000 remaining tigers on earth? Is the diversity of opinions expressed in the written press greater in France than in the US? Is the choice of models of cars offered more diverse at General Motors than at Volkswagen? In order to put the Rio or the UNESCO convention into force, or to study the impact of concentration of the media industry on the diversity of opinions expressed in the media, it is of some importance to have available clear yet accurate answers to questions such as these. I propose in this chapter to critically examine some of the approaches that have been proposed in various disciplines – biology and economics for the most part – for answering such questions.
