Hypothetico-deductivism in systematics: fact or fiction?

Realism in systematics through biogeographical consilience

There is an overlooked gap between any phylogenetic hypothesis and the natural world shaped by historical evolutionary processes, since the main concern during phylogenetic analyses is solely the search for congruence among characters under a defined criterion. Given a scientific realistic view, however, phylogenetic hypotheses are scientific theories that try to depict the historical series of cladogenetic events among biological entities. In this sense, the challenge is to establish a form of measuring the degree of truthfulness of our phylogenetic hypotheses. Here, we advocate the use of consilient biogeographical hypotheses to recognize the biological meaning of a phylogenetic inference apart from its instrumentalist value. Our proposal is based on the assumption that robust biogeographical hypotheses allows us to be close to the real evolutionary history of taxa. © The Willi Hennig Society 2011.

Pattern cladistics and the 'realism-antirealism debate' in the philosophy of biology

Despite the amount of work that has been produced on the subject over the years, the 'transformation of cladistics' is still a misunderstood episode in the history of comparative biology. Here, I analyze two outstanding, highly contrasting historiographic accounts on the matter, under the perspective of an influential dichotomy in the philosophy of science: the opposition between Scientific Realism and Empiricism. Placing special emphasis on the notion of 'causal grounding' of morphological characters (sensu Olivier Rieppel) in modern developmental biology's (mechanistic) theories, I arrive at the conclusion that a 'new transformation of cladistics' is philosophically plausible. This 'reformed' understanding of 'pattern cladistics' entails retaining the interpretation of cladograms as 'schemes of synapomorphies', but in association to construing cladogram nodes as 'developmental-genetic taxic homologies', instead of 'standard Darwinian ancestors'. The reinterpretation of pattern cladistics presented here additionally proposes to take Bas Van Fraassen's 'constructive empiricism' as a philosophical stance that could properly support such analysis of developmental-genetic data for systematic purposes. The latter suggestion is justified through a reappraisal of previous ideas developed by prominent pattern cladists (mainly, Colin Patterson), which concerned a scientifically efficient 'observable/non-observable distinction' linked to the conceptual pair 'ontogeny and phylogeny'. Finally, I argue that a robust articulation of Antirealist alternatives in systematics may provide a rational basis for its disciplinary separation from evolutionary biology, as well as for a critical reconsideration of the proper role of certain Scientific Realist positions, currently popular in comparative biology.