They are correct that punctuated equilibria apply to sexually reproducing organisms and that morphological evolutionary change is regarded as largely (if not exclusively) correlated with speciation events. However, they err in suggesting that we attribute stasis strictly to "developmental constraints," which represent only one of a set of possible mechanisms that we have suggested for the causes of stasis. Others include habitat tracking and the internal structure of species themselves [for example, (2)].

My thesis is that biology is most plausibly regarded as a universal, as distinct from a provincial, science. First, I develop the general notion of a provincial science, formulate three criteria for applying the concept, and present brief examples illustrating their use. Second, I argue that a consideration of population genetics as a characteristic example of a basic biological theory strengthens the prior presumption that biology is not a provincial science. Finally, I examine two arguments to the effect that biology (...) is a provincial science. The first concerns biology's exclusively terrestrial evidence base, the second the logical character of its laws. I introduce considerations that weaken the persuasiveness of the first argument and then show that the second one rests upon a false premise and so should be rejected. (shrink)

History of science, it has been argued, has benefited philosophers of science primarily by forcing them into greater contact with "real science." In this paper I argue that additional major benefits arise from the importance of specifically historical considerations within philosophy of science. Loci for specifically historical investigations include: (1) making and evaluating rational reconstructions of particular theories and explanations, (2) estimating the degree of support earned by particular theories and theoretical claims, and (3) evaluating proposed philosophical norms for the (...) evaluation of the degree of support for theories and the worth of explanations. More generally, I argue that theories develop and change structure with time, that (like biological species) they are historical entities. Accordingly, both the identification and the evaluation of theories are essentially historical in character. (shrink)

A central subject is the main strand around which the fabric of an historical narrative is woven. Such a subject must possess both spatial and temporal continuity. It is integrated into an historical entity through the relationship between those properties which make it an individual, and their interaction with the historical event. Scientific theory is useful in the reconstruction of past events and the definition of the central subject. Ideas used as central subjects present the problem of finding internal principles (...) of integration which will make the idea continuous over time. The purpose of narratives is to explain an event by integrating it into an organized whole. (shrink)

The foundations of systematics lie in ontology, not in subjective epistemology. Systems and their elements should be distinguished from classes; only the latter are constructed from similarities. The term classification should be restricted to ordering into classes; ordering according to systematic relations may be called systematization.The theory of organization levels portrays the real world as a hierarchy of open systems, from energy quanta to ecosystems; followingHartmann these systems as extended in time are considered the primary units of reality. Organization levels (...) should be distinguished from levels of differentiation within each organization level.Certain biological systems, such as species, continue to be misinterpreted as classes, particularly by logicians unfamiliar with modern biological theory. Replacement of Aristotelian definitions of species by “polytypic” definitions achieves nothing, because species are individual systems which can be defined from an ontological viewpoint only as wholes. The dispute whether classes are real per se or only in individuals is of no scientific importance; irrespective of which view is taken, any ordering of physical objects into classes constitutes an hypothesis about the structure of the real world.The distinction between essential and contingent characters is relevant only to classification. There are no universal rules for evaluating characters for purposes of systematization. Character statements do not form separate linear sequences. The search for “unit characters” in an absolute sense is futile. All real characters are reducible to relations and are in principle measurable, although there are limitations on the extent to which this can be presently achieved.The concept of the sexual species is fundamental to theories of biosystematics. Sexual species may be defined as lineages consisting at any given time of series of populations between which genetic exchange can occur and delimited in time by two successive processes of speciation. Linnaean nomenclature needs modification; in its traditional form it is appropriate only to non-truncated hierarchies, whereas real phylogenies form truncated hierarchies. In consequence of the distinction between systematization and classification it is concluded that, while taxa may be classified into age classes or evolutionary grades, their limits as taxa can be no different in either case. Classification into evolutionary grades remains an imprecise endeavour, since no general measure of evolutionary differentiation has been devised.The spatial and temporal extent of ecosystems, the postulated basic units of ecosystematics, remains unclarified. Nevertheless there are grounds for expecting progress in this field as the energetic relations between organisms become better understood. Biotic communities are not “abstract” classes, but systematic units. Physiognomic classification should not be confused with systematization of plant communities; both approaches contribute to an understanding of vegetational structure. (shrink)

The notion of possible worlds — once an abstruse offspring of Leibnizian theology — seems to enjoy a new lease on life in the hands of contemporary modal logicians and semanticists. The phrase “possible world” crops up with increasing frequency, and, as it is the case with many philosophical catchwords, its very familarity creates a presumption of understanding. Yet, although some related problems, particularly the one concerning cross-world identification of individuals, have received some critical scrutiny, the very idea of possible (...) worlds has been borrowed from Leibniz, and its intelligibility taken for granted even without its theological roots.My misgivings about this notion are not due to a prejudice against the concept of the possible itself: far from “passing” away, it remains a fundamental and irreplaceable element of human thought. (shrink)