ABSTRACT
“How shall we classify?” is a scientific or technological question, a problem for applied mathematics. There is a prior epistemological question as to how we evidence a category’s reality and a pragmatic question, “Why do we want to classify anyway?” I ask this question not rhetorically but seriously, unlike some dogmatic antinosologists, who wrongly think we know there cannot be any categories of personality or mental disorder. The truth is that we usually do not know whether we are dealing with categories or with dimensions, and in the past we have not had a sound method for finding out the true state of affairs. My interest in developing new taxometric statistics was partly motivated by clinical concerns as a practitioner but was mainly motivated by a theoretical problem: how to test competing genetic models for inheritance of the schizophrenic predisposition—in my theory, schizotaxia, a neurological defect that leads to diagnosable schizophrenic illness in only a small fraction of those who have the genotype (Meehl, 1962, 1972b, 1989b, 1990c, 1990d).
