protect every species. On the contrary, Kant was clear in distinguishing the obligatory from the supererogatory, that is, actions that are morally praiseworthy but go beyond the call of duty. Kantians would be comfortable using economic analysis to structure incentives so that we can get the most species protection at the lowest cost.
Randall and Farmer (1995) have argued that utilitarianism, contractarianism, and Kantian ethics could accept, for different reasons, a safe minimum of conservation for species, habitats, and ecosystems. However, the different philosophical frameworks are likely to disagree about the subset of biodiversity that deserves such protection and about the conditions under which human society would be justified in abandoning the safe minimum because it demanded "too much" sacrifice.
Egalitarianism would insist on special concern for the welfare of the worst-off human beings; this has unclear and not necessarily favorable implications for concern for biodiversity. The environmental-justice approach might well demand protection of biodiversity in impoverished places and for impoverished people but is likely to encounter opposition from those who believe that the impoverished have more pressing concerns.
Deep ecology could take any of the basic utilitarian, contractarian, or Kantian ethical approaches and extend the category of things that matter (whose welfare is a concern, that have rights, or that have "a good of their own") to all or some of the elements of biodiversity. A major thrust would be to ground the claims of natural heritage independently of human value and belief so that humans would be obliged categorically (not just as it suited them individually) to honor these claims.
Discursive ethics is really a process—and a relatively loosely defined process at that. Its promise lies in determining and expressing genuinely social values inherent in biodiversity as opposed to the aggregation of individual values that utilitarism would promote.
This chapter reviewed the main Western philosophies of value. This provides a context for the description in the next chapter of how the tools of economics contribute to understanding biodiversity values in relation to resource-management decisions. Understanding the implications of these various philosophies for valuing biodiversity is important for public-resources managers, who must deal with different value philosophies in their decisions.
Bentham J. 1986. An introduction to the principles of morals and legislation: special edition. Legal Classics Library.