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About nothing
Author(s) -
Brower Andrew V. Z.,
Pinna Mario C. C.
Publication year - 2014
Publication title -
cladistics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.323
H-Index - 92
eISSN - 1096-0031
pISSN - 0748-3007
DOI - 10.1111/cla.12050
Subject(s) - synapomorphy , cladistics , character (mathematics) , meaning (existential) , nothing , ontology , taxon , epistemology , biology , philosophy , paleontology , phylogenetics , mathematics , genetics , clade , geometry , gene
Abstract In light of recent terminological controversy, this article reviews cladistic conceptions of character states coded as absences, symplesiomorphies, and secondary losses. The first section addresses absence as a question of ontology vs. epistemology. The second and third sections address the evidentiary status of symplesiomorphy in cladistics, the fourth contrasts primitive absence with secondary loss, and the fifth clarifies the meaning of “grouping”. While secondary losses (reversals) are often synapomorphies, symplesiomorphies (“absent” or otherwise) have no evidentiary import to cladistic hypotheses of relationship. Thus, we argue that identifying symplesiomorphic character states as “homologous” is conceptually vacuous, because they are either synapomorphies (homologues) of more inclusive taxa, or complementary absences that unite no group.