Hypothetico-deductivism in systematics: fact or fiction?

Abstract

Phylogenetic systematics (the cladistic analysis of phylogenetic relationships) is not hypotheticodeductively structured (in the sense of a covering law model of scientific explanation). If it were, there would be no reason to call for total evidence, since that requirement is automatically satisfied in a deductively structured explanation. Instead, the appeal to the requirement of total evidence in phylogenetic systematics indicates that phylogenetic inference is inductively, or abductively, structured. The principle of total evidence has been invoked to render inductive inference an argument as strong as it can be, but for this to be the case the total evidence must also be relevant evidence, i.e., evidence 'of the right sort' relative to the state of affairs to be explained. Character congruence is a necessary condition for phylogenetic inference, but not also a sufficient condition. What is required in addition is the causal grounding of character statements in theories of inheritance, development and function.

The series, the network, and the tree: changing metaphors of order in nature

“…The test of cladograms, and synapomorphies, is therefore not properly hypothetico-deductively structured (Rieppel 2008c), falsifiability in systematics hence here referred to as (quasi-)Popperian. According to cladistic theory, there is no need (nor any possibility) to reliably and a priori distinguish 'true' synapomorphy from convergence, reversals, or simply observer error, as long as synapomorphy, and through them cladograms, can be tested, and potentially refuted (Kluge 2003).…”

Pattern Cladistics and the ‘Realism–Antirealism Debate’ in the Philosophy of Biology

“…Nevertheless, I consider that Olivier Rieppel's interventions to place the R-AR debate at a prominent site in theoretical systematics have already had an effect, in as much as they are part of a more formal and sophisticated philosophical project. 43 Rieppel's interest in the philosophy of systematics is not new, 44 but during the past 6 years- Rieppel and Kearney (2002) and Rieppel (2008) are two publications that might bracket the period well -he has taken it to a higher level of complexity by focusing on the identification of 'Hennig's lost intellectual affinities', 45 under the auspices of updated philosophical sources. Like Ebach and Williams', Rieppel's work has a historiographic component.…”

“…In this regard, it should be noticed that Rieppel's effort to probe inside 'every neuron in Hennig's brain' 46 has simultaneously supported his progressive rejection of Popperianism-almost by necessity, the philosophical discourse that subtended the interpretation of cladistics during his own previous phase as a cladist. Such departure has, in its latest version, pictured hypothetico-deductivism in systematics as a 'fiction' that could be safely dismissed (Rieppel 2008; see also Rieppel 2003Rieppel , 2004; see Notes 11 and 13). The richness of arguments implicit in Rieppel's 'anti-Popperian turn', in my view, warrant that a future, careful critical analysis is conducted on them-just as Rieppel has seen fit to focus exhaustively on Hennig's ideas.…”

“…However, like the prestigious philosopher of science Elliot Sober (whom has also never shown much sympathy for 'transformed cladistics'; see, for instance, Sober 2000, p. 186), Hull has consistently stated that hypothetico-deductivism has no valid application in cladistics (Hull 1983(Hull , 1988(Hull , 1989. Olivier Rieppel's recent criticisms of Popperianism in systematics are partially indebted to Hull's views (see, for instance, Rieppel 2003Rieppel , 2008; further comments on some of Rieppel's important contributions to current philosophy of systematics are mentioned elsewhere in this article). It is worth noting that Williams and Ebach (2007, p. 113) also find no merit in advocating Popperian views in (C/c)ladistics (see Note 10).…”

Realism in systematics through biogeographical consilience

“…This is an instrumentalist perspective: the measure of confirmation of the theory is not given by its accordance to the natural world, but rather to the accordance among the sentences that compose the theory. Although there seems to be no room for prediction in phylogenetic analyses (Rieppel et al., 2006; Rieppel, 2008) and, as said before, instrumentalism advocates hypotheses only as tools to generate predictions, an instrumentalist perspective is a very pervasive approach throughout contemporary systematics. It is conducted in a manner similar to that proposed by the empiricist Bas van Fraassen in the so‐called “constructive‐empiricism” (see Vergara‐Silva, 2009, and references therein).…”