Just as there are different psychotherapeutic schools that in part contradict or differ from each other quite significantly in terms of their theoretical assumptions, there are also at least four major schools in psychometrics that also take different approaches and contradict each other. By contrast, there is only one form – as a rule integrative or eclectic – of psychotherapeutic or psychomotor practice. But how can such a practice be legitimized in theoretical terms? A persuasive answer to this question has yet to be found.The present study is an attempt – using psychomotor practice and science as an example – to present a first comprehensive answer to this question. It thus provides the epistemological framework for an eclectic, integrative approach in and beyond the study of psychomotoric therapy and motology.