At least 22 concepts of species are in use today and many of these are notably incompatible in their accounts of biological diversity. Much of the traditional turmoil embodied in the species problem ultimately derives from the packaging of inappropriate criteria for species into a single concept. This results from a traditional conflation of function of concepts with their applications, definitions with concepts, taxonomic categories with groups, and the ontological status of real species with teleological approaches to recover them. Analogous (...) to classifications of supraspecific taxa, our forging inappropriate and ambiguous information relating to theoretical and operational discussions of species ultimately results in a trade-off between convenience, accuracy, precision, and the successful recovery of natural biological diversity. Hence, none of these expectations or intentions of species or classifications is attainable through composite, and possibly discordant, concepts of biological diversity or its descent. Reviewing and evaluating the concepts of species for their theoretical and operational qualities illustrates that a monistic, primary concept of species, applicable to the various entities believed to be species, is essential. This evaluation reveals only one theoretical concept as appropriate for species, the Evolutionary Species Concept. This conceptualization functions as a primary concept and is essential in structuring our ideas and perceptions of real species in the natural world. The remaining concepts are secondary, forming a hierarchy of definitional guidelines subordinate to the primary concept, and are essential to the study of species in practice. Secondary concepts should be used as operational tools, where appropriate, across the variance in natural diversity to discover entities in accord with the primary concept. Without this theoretical and empirical structuring of concepts of species our mission to achieve reconciliation and understanding of pattern and process of the natural world will fail. (shrink)

Stable URL: http://links.jstor.org/sici?sici=0048-3915%28198923%2918%3A4%3C334%3AAIACTD%3E2.0.CO%3B2-P..

I wish to examine a rather different way of thinking about permissibility, one according to which, roughly speaking, an agent acts impermissibly if and only if he acts for reasons insufficient to justify him in doing what he does. For reasons that will emerge in Section II, I call this the inferential account of permissibility. I shall not here try to prove that this account is superior to its rivals. My aims are more modest. I shall develop the inferential account, (...) exhibiting some of its attractions along the way, and then show that it is invulnerable to a number of influential objections to the very idea that an agent's reasons for acting could be directly relevant to whether he acts permissibly. If these objections have seemed decisive, it is because we have not considered the full range of possible accounts. The inferential account of permissibility is both plausible and attractive---it deserves to be taken seriously. (shrink)