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A falsificationist perspective on the usage of process frequencies in phylogenetics
Author(s) -
Vogt Lars
Publication year - 2007
Publication title -
zoologica scripta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.204
H-Index - 64
eISSN - 1463-6409
pISSN - 0300-3256
DOI - 10.1111/j.1463-6409.2006.00277.x
Subject(s) - cladogram , cladistics , weighting , comparative biology , congruence (geometry) , phylogenetics , biology , consistency (knowledge bases) , epistemology , evolutionary biology , computer science , psychology , artificial intelligence , social psychology , philosophy , medicine , biochemistry , radiology , gene
By referring to Popperian falsificationism, proponents of cladistic parsimony claim the superiority of parsimony over likelihood. They conclude that likelihood as a statistical approach is inconsistent with falsificationism, and base their argumentation on four claims: (1) congruence tests cladograms against observational evidence and represents the most important test in phylogenetics, in which minimum‐step trees represent most corroborated trees; (2) frequency probabilities cannot be used for evaluating degree of corroboration; (3) phylogeny represents a unique process and thus frequencies cannot be applied as they require statistical reference classes that are necessarily general; (4) likelihood is a verificationist approach. After discussing the deficiencies of the cladistic phylogeneticists’ conceptualisation of the congruence test and the presentation of an alternative conceptualisation, it is shown that these four claims cannot be sustained within a falsificationist framework, and that the weighting of characters is a necessity. A differentiation between the theoretical concept of apomorphy and the epistemological concept of character weight is proposed. While apomorphies have to be independent from each other, the weighting of characters is interdependent due to human inability to distinguish organismic traits that are structurally identical though they do not share a common evolutionary origin. The possibility of this epistemological interdependence can best be dealt with by the application of process frequencies. The importance of process frequencies of specific transformation classes is exemplified in reference to Popper's formula for the measure of degree of corroboration and its consistency is shown. Therefore, the application of statistical methods is reasonable. As a consequence, the question whether likelihood or parsimony methods represent the best approaches in phylogenetics remains a genuinely empirical question that cannot be decided only in reference to Popper's falsificationism.