Characters as units and the case of the presence and absence hypothesis

This paper discusses the individuation of characters for the use asunits by geneticists at the beginning of the 20^th century. Thediscussion involves the Presence and Absence Hypothesis as a case study. It issuggested that the gap between conceptual consideration and etiological factorsof individuating of characters is being handled by way of mutual adjustment.Confrontation of a suggested morphological unit character with experimentresults molded the final boundaries of it.