Walter Bock was committed to developing a framework for evolutionary biology. Bock repeatedly discussed how evolutionary explanations should be considered within the realm of Hempel’s deductive-nomological model of scientific explanations. Explanation in evolution would then consist of functional and evolutionary explanations, and within the latter, an explanation can be of nomological-deductive and historical narrative explanations. Thus, a complete evolutionary explanation should include, first, a deductive functional analysis, and then proceed through nomological and historical evolutionary explanations. However, I will argue that (...) his views on the deductive proprieties of functional analysis and the deductive-nomological parts of evolution fail because of the nature of evolution, which contains a historical element that the logic of deduction and Hempel’s converting law model do not compass. Conversely, Bock’s historical approach gives a critical consideration of the historical narrative element of evolutionary explanation, which is fundamental to the methodology of the historical nature of evolutionary theory. Herein, I will expand and discuss a modern view of evolutionary explanations of traits that includes the currentacknowledgement of the differences between experimental and the historical sciences, including the token and type event dichotomy, that mutually illuminate each other in order to give us a well confirmed and coherent hypothesis for evolutionary explanations. Within this framework, I will argue that the duality of evolutionary explanations is related to two components of character evolution: origin, with its evolutionary pathways along with the history, and maintenance, the function (mainly a current function) for the character being selected. (shrink)

This article is a study of the role and use of evidence in the evaluation of claims in the historical sciences. In order to do this, I develop a “snapshot” approach to Toulmin schemas. This framework is applied to the case of Archezoa, an initially supported then eventually rejected hypothesis in evolutionary biology. From this case study, I criticize Cleland’s “smoking gun” account of the methodology of the historical sciences. I argue that Toulmin schemas are conceptually precise tools that allow (...) for the building of enriched reconstructions of evidential reasoning. From the application of this framework, I discuss three ways in which the construction and use of facts in the historical sciences are theory-laden. Despite its inherent limits, TS are heuristically useful tools to identify epistemic moves that could be further investigated. It also sheds light on the positive roles of speculation in the historical sciences. Finally, I argue that it provides a context-specific and individuated understanding of hypothesis evaluation in the historical sciences. Overall, I think the application of Toulmin schemas to cases of evidential reasoning in the historical sciences is a promising descriptive and heuristic tool for philosophers of science. (shrink)

Philosophers have usually highlighted how the weakness and paucity of historical evidence underdetermine the choice between rival historical explanations. Focusing underdetermination on the link between theory and evidence comes, I argue, with three assumptions: competing hypotheses are easy to generate, investigators agree on the constitution and interpretation of the evidence and a plurality of hypotheses is a useful evil to reach consensus. The last assumption implies that the sustained coexistence of incompatible hypotheses is considered as a scientific failure. I argue (...) that this negative vision of sustained disagreement has monistic undertones. By drawing from a case study in evolutionary biology, this paper defends a form of scientific pluralism. Firstly, I show that underdetermination is not only found at the inferential level but also at the level of the constitution and interpretation of the evidence, on the choice of investigative scaffolds and when interpreting background theories. Because of that, competing hypotheses exhibit a degree of methodological incommensurability. While catastrophic from a monistic standpoint, I defend that scientific pluralism gives a different, and I think richer, account of such situations. On the plus side, competing approaches benefit from their sustained coexistence and interaction. I argue that this generates direct and indirect epistemic goods independently of whether the controversy is solved. Scientific pluralism also shifts our attention from achieving consensus to managing disagreement. The challenge becomes to maintain the conditions for fruitful interactions in a community with incommensurable approaches and heterogeneous expertise. (shrink)

Framing systematics as a field consistent with scientific inquiry entails that inferences of phylogenetic hypotheses have the goal of producing accounts of past causal events that explain differentially shared characters among organisms. Linking observations of characters to inferences occurs by way of why-questions implied by data matrices. Because of their form, why-questions require the use of common-cause theories. Such theories in phylogenetic inferences include natural selection and genetic drift. Selection or drift can explain ‘morphological’ characters but selection cannot be causally (...) applied to sequences since fitness differences cannot be directly associated with individual nucleotides or amino acids. The relation of selection to sequence data is by way of downward or top-down causation from those phenotypes upon which selection occurs. The application of phylogenetic inference to explain sequence data is thus restricted to instances where drift is the relevant theory; those nucleotides or amino acids that can be explained via downward causation are precluded from inclusion in the data matrix. The restrictions on the inclusion of sequence data in phylogenetic inferences equally apply to species hypotheses, precluding the more restrictive approach known as DNA barcoding. Not being able to discern drift and selection as relevant causal mechanisms can severely constrain the inclusion and explanations of sequence data. Implications of such exclusion are discussed in relation to the requirement of total evidence. (shrink)

Three competing ‘methods’ have been endorsed for inferring phylogenetic hypotheses: parsimony, likelihood, and Bayesianism. The latter two have been claimed superior because they take into account rates of sequence substitution. Can rates of substitution be justified on its own accord in inferences of explanatory hypotheses? Answering this question requires addressing four issues: (1) the aim of scientific inquiry, (2) the nature of why-questions, (3) explanatory hypotheses as answers to why-questions, and (4) acknowledging that neither parsimony, likelihood, nor Bayesianism are inferential (...) actions leading to explanatory hypotheses. The aim of scientific inquiry is to acquire causal understanding of effects. Observation statements of organismal characters lead to implicit or explicit why-questions. Those questions, conveyed in data matrices, assume the truth of observation statements, which is contrary to subsequently invoking substitution rates within inferences to phylogenetic hypotheses. Inferences of explanatory hypotheses are abductive in form, such that some version of an evolutionary theory(ies) is/are included or implied. If rates of sequence evolution are to be considered, it must be done prior to, rather than within abduction, which requires renaming those putatively-shared nucleotides subject to substitution rates. There are, however, no epistemic grounds for renaming characters to accommodate rates, calling into question the legitimacy of causally accounting for sequence data. (shrink)