The article defends the doctrine that Linnaean taxa, including species, have essences that are, at least partly, underlying intrinsic, mostly genetic, properties. The consensus among philosophers of biology is that such essentialism is deeply wrong, indeed incompatible with Darwinism. I argue that biological generalizations about the morphology, physiology, and behavior of species require structural explanations that must advert to these essential properties. The objection that, according to current “species concepts,” species are relational is rejected. These concepts are primarily concerned with (...) what it is for a kind to be a species and throw little light on the essentialist issue of what it is for an organism to be a member of a particular kind. Finally, the article argues that this essentialism can accommodate features of Darwinism associated with variation and change. (shrink)

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)

A discussion of several tensions between Thomistic philosophy and modern Darwinian theory as well as several recent Thomistic criticisms of intelligent design.

The Development of Modern Taxonomy Taxonomy has a long history, going back to the ancient Greeks and to forerunners even less sophisticated in systematics. Our interest here is centered on modern taxonomy itself, and we shall largely ...

The purpose of this paper is to lay bare the major problems underlying the concept of downward causation as discussed within the perspective of the present interest for phenomena that are characterized by self-organization. In our discussion of the literature, we have focussed on two questions: (1) What sorts of things are said to be, respectively, causing and caused within the context of downward causation? And (2) What is the meaning of ‘causing’ in downward causation? We have concluded that the (...) concept of ‘downward causation’ is muddled with regard to the meaning of causation and fuzzy with regard to the nature of the causes and the effects. Moreover, we have concluded that ‘causation’ in respect of ‘downward causation’ is usually understood in terms of explanation and determination rather than in terms of causation in the sense of ‘bringing about’. Thus, the term ‘downward causation’ is badly chosen. (shrink)