It is pointed out that many published empirical studies on the issue o
f borderline conditions suffer from methodological shortcomings due to
the prevailing empiricist simplification of research. Attention is dr
awn to the fact that the current psychiatric research in classificatio
n issues is dominated by an exaggerated quest for reliability at the e
xpense of concern with validity issues. Concepts of operational criter
ia, polythetic-prototypic systems, and epistemic peculiarities of psyc
hiatric, clinical typification are briefly exposed. It is suggested th
at future scientific progress in the area of personality research must
take into account these general methodological considerations: repote
ntiate clinical-phenomenological observation, include prototypical app
roaches, extend studied samples with subjects drawn from the general p
opulation and import insights from personality trait research in norma
l psychology. Some of the claims of Gunderson and Torgersen (this volu
me) are discussed.