Using the context of controversies surrounding evolutionary developmental biology (EvoDevo) and the possibility of an Extended Evolutionary Synthesis, I provide an account of theory structure as idealized theory presentations that are always incomplete (partial) and shaped by their conceptual content (material rather than formal organization). These two characteristics are salient because the goals that organize and regulate scientific practice, including the activity of using a theory, are heterogeneous. This means that the same theory can be structured differently, in part because (...) theory presentations (as idealizations) intentionally depart from different features known to be present in a theory. Since there are diverse and potentially incompatible theory structures derived from heterogeneous goals found in scientific practices, a question arises about the absence of a unifying theory structure in the background. The notion of a “theory façade” offers a fruitful perspective on this potentially unsettling result. (shrink)

The goal of evolutionary theory is to (a) specify the general causal structure of evolving systems and (b) analyze evolutionary consequences that are expected to result from the proposed structure of the model systems. Biologists frequently emphasize the hypothetico-deductive method in evolutionary theory. I will show that this method primarily provides a tactical device for (b), while evolutionary synthesis requires a foundation of a unifying conceptual model for (a). Therefore, any successful strategy for a new synthesis requires both a new (...) conceptual insight of evolving systems, and tactical devices for analyzing new specific aspects of the evolutionary process. (shrink)

The term “genetic load” first emerged in a paper written in 1950 by the geneticist H. Muller. It is a mathematical model based on biological, social, political and ethical arguments describing the dramatic accumulation of disadvantageous mutations in human populations that will occur in modern societies if eugenic measures are not taken. The model describes how the combined actions of medical and social progress will supposedly impede natural selection and make genes of inferior quality likely to spread across populations – (...) a process which in fine loads their progress. Genetic load is based on optimal fitness and emerges from a “typological view” of evolution. This model of evolution had previously, however, been invalidated by Robert Wright and Theodosius Dobzhansky who, as early as 1946, showed that polymorphism was the rule in natural populations. The blooming and persistence of the concept of genetic load, after its theoretical basis had already expired, are a historical puzzle. This persistence reveals the intricacy of science and policy-making in eugenic matters. The Canguilhemian concept of ‘scientific ideology’ is used along with the concept of ‘immutable mobile’ and compared with the concept of ‘co-production’, to provide complementary perspectives on this complex phenomenon. (shrink)

The Evolutionary Synthesis is often seen as a unification process in evolutionary biology, one which provided this research area with a solid common theoretical foundation. As such, neo-Darwinism is believed to constitute from this time onward a single, coherent, and unified movement offering research guidelines for investigations. While this may be true if evolutionary biology is solely understood as centred around evolutionary mechanisms, an entirely different picture emerges once other aspects of the founding neo-Darwinists’ views are taken into consideration, aspects (...) potentially relevant to the elaboration of an evolutionary worldview: the tree of life, the ontological distinctions of the main cosmic entities , the inherent properties of self-organizing matter, evolutionary ethics, and so on. Profound tensions and inconsistencies are immediately revealed in the neo-Darwinian movement once this broader perspective is adopted. This pluralism is such that it is possible to identify at least three distinct and quasi-incommensurable epistemological/metaphysical frameworks as providing a proper foundation for neo-Darwinism. The analysis of the views of Theodosius Dobzhansky, Bernhard Rensch, and Ernst Mayr will illustrate this untenable pluralism, one which requires us to conceive of the neo-Darwinian research agenda as being conducted in more than one research programme or research tradition at the same time. (shrink)

The impact of philosophy of science on biology is slight. Evolutionary biology, however, is nowadays an exception. The status of the neo-Darwinian theory of evolution is seriously challenged from a methodological perspective. However, the methodology used in the relevant discussions is plainly defective. A correct application of methodology to evolutionary theory leads to the following conclusions. The theory of natural selection is unfalsifiable in a strict sense of the term. This, however, does not militate against the theory, because no scientific (...) theory whatever is testable in this way. Under a more liberal testability criterion, the theory is surely testable. None the less, certain research programs may tend to make the theory untestable in practice. It has often been argued that the tautologous character of the principle of natural selection, allegedly the focus of evolutionary theory, makes the theory untestable through circular reasoning. Actually, the principle is only a tautology if ‘fitness’ is wrongly defined in terms of actual survival. But even then circular reasoning need not ensue. Evolutionary principles do not permit, without additional information, the derivation of statements about evolutionary events concerning particular species or populations. If this were a reason to criticize the theory , any other scientific theory would be inadequate by the same token. (shrink)

It is clear from the above discussion that if I had wished to do so I could have truthfully presented every paper as either testing a prediction, presenting evidence needed in the test of a prediction, or presentin a D-N explanation. (I would not have been able to do this if I had not been sufficiently familiar with the evolutionary literature to recognize what hypotheses were at stake in several of the papers; even when the authors mention the hypotheses they (...) frequently do so only in enough detail to put their paper in context for the knowledgeable biologist.) Since these biologists are working in a period of normal science under the paradigm of the modern synthetic theory of evolution, none of these papers is presented as a test of the modern synthetic theory; but since this theory was used in the derivation of each prediction, each one is a test of it as well as of the hypothesis mentioned. Thus, once we learn to recognize the predictions beneath their cloaks of invisibility, we discover that prediction testing is not, as philosophers have claimed, at best peripheral to evolutionary biology; it is central to evolutionary biology. (shrink)