ABSTRACT
There is more than one reason why biodiversity is, for environmental ethics, a ‘hard case’. One reason is that the concept easily defies definition. Like simplicity (a concept that plays a crucial role in the philosophy of science and scientific methodology), diversity seems intuitively easy to grasp but, on a closer look, proves to be a concept of considerable complexity. What does it mean to say that a natural system is ‘diverse’, absolutely or to a certain degree? What are the items on which biodiversity is predicated: biological species, alleles, or the various properties of natural systems? If properties, should only biological properties be included, or also non-biological ones such as aesthetic and symbolic properties, which play an important role in the psychology and the politics of conservation? Should the mere number of items count, or should diversity be defined by some qualitative measure, e.g. by the amount of difference between the items considered, provided these differences are in some way significant? Obviously, counting is not enough. Even a picture that is black all over can exhibit a great diversity of shades of black, but that would not be sufficient to make it particularly diverse in colour. The distinction, customary in ecology, between species diversity, ecosystem diversity and genetic diversity shows that the concept of biodiversity is in need of specification to make it commensurate with the findings and theories in various biological disciplines. The biological distinction is certainly helpful as a first step, but what is needed for an ethical analysis is an inclusive concept of biodiversity, covering all relevant dimensions.
