| Considering the official role species play in evolution, there is surprisingly little agreement among scientists or philosophers about what sort of entities species are. Many of the difficulties originate from wholly unexamined, faulty presuppositions about change and causation that characterize most thinking in modern science and philosophy. Thus, since species are essentially bound up with evolutionary change, a coherent account of their nature will require in turn a metaphysically disciplined understanding of change. This study provides both.;This study considers the known activities of species and surveys views advanced by biologists such as Mayr, Ghiselin, Simpson, Gould, and Dawkins. While competing definitions abound, all ultimately fall into one of two camps. Species are conceived either as real "individual" beings, or as class concepts. Accordingly, these camps debate species' ontological status. However, the debate is unresolvable because neither position is tenable. Actual evidence indicates species are neither individual beings such as organisms are, nor mere class concepts, such as the higher taxa are. The problem is that, wittingly or not, nearly all parties to the debate share an underlying reductionist ontology and corresponding view of causation that cannot explain the observed facts. These assumptions, which are methodological in their origin, are inadequate to explain the general phenomenon of evolutionary change, much less the role of species in it. Thus does the unique nature of species challenge the implicit metaphysical framework of science.;Taking bearings from Aristotle's metaphysics, this study supplies a framework from which to explain species' observed nature. Of utmost importance is the principle of change, potentiality (dunamis). Its recovery as a mode of being casts light on species' role in evolution and likewise on their ontological status. More generally, the principles of actuality and potentiality, together with that of function or final cause (hou heneka), all help portray the ontological and causal complexity of species. Recent work in the science of complexity is beginning to corroborate insights long known to Aristotle and Hegel, namely, that "complexity" and all it entails is evident in all entities when their dynamic as well as their formal natures are brought into consideration. |
