The Polarization of Character Transformations in Phylogenetic Systematics: Role of Axiomatic and Auxiliary Assumptions

Methods of polarity determination are governed by both the basic assumptions of the analysis and particular auxiliary assumptions. Differences in basic assumptions between phylogenetic systematics and pattern cladistics result in different approaches to polarity determination. In phylogenetic systematics outgroup comparison, the ontogenetic method and the paleontological method are valid procedures for determining polarity because they can be derived from basic evolutionary axioms. The applicability of each method of polarization in particular instances depends on the veracity of auxiliary assumptions. Auxiliary assumptions entail necessary conditions implicit in the rationale of the method or the adequacy of available information. Each method has a unique combination of auxiliary assumptions and is not a special case of, or dependent on, other methods. Much of the recent debate regarding the overall relative applicability of the three methods suffers from the failure to properly consider auxiliary assumptions. Outgroup comparison has the broadest utility, but the applicability and utility of all methods should be considered in each instance. [Phylogenetic systematics; character transformation; axioms; auxiliary assumptions; outgroup comparison; ontogenetic method; paleontological method.]