Original paper

Problematic issues of cladistics: 24. Shoehorning, and the logic of absolute and relative phylogenetic relationship

Reif, Wolf-Ernst


Both, evolutionary systematics and phylogenetic systematics (cladistics) have claimed that phylogenetic relationship is analogous to genealogy. This sentence is meaningless. It requires first of all that in genealogy and in phylogenetics three kinds of relationship are distinguished: general, absolute and relative. Genealogy works with the absolute relationships among well-defined individuals. Shoehorning and evolutionary systematics try to clarify absolute degrees of relationship among taxonomic groups whose delimitation requires conventions. These methods also require complete descriptions of forms and measurements of their differences which incurs typological pitfalls. Cladistics, on the other hand works only with differences of character states and relative phylogenetic relationship. The background of HENNIG's phylogenetic systematics is represented by three relativistic principles: relativity of character state, relativity of phylogenetic relationship and relativity of (position and rank) of taxa.


crafoord lecturesphylogenetic systematicsevolutionary systematicsmonophylyapomorphy