Numerical Homology

Abstract

THERE have recently been many objections to the orthodox definitions of biological homology in terms of common ancestry on the grounds that such definitions are circular^1–4. Parts of two organisms are defined as homologous if they are represented by a single part in a common ancestor. But homology itself is invoked in making this identification of parts of organisms with a part in a common ancestor. Various authors have advocated a return to Owen's⁵ criterion of homology—“the correspondency of a part or organ, determined by its relative position and connexions, with a part or organ in a different animal”. Jardine⁶ has formulated a logical model for correspondence of parts of things with respect to a set of relations along lines suggested by Woodger³, and from it has derived a general method for finding such correspondences.