It is the purpose of this article to offer additional clarification of H. S. Sullivan's three-way division of cognitive experience. The investigation involves an analysis of C. S. Peirce's phenomenological categories of experience and their three Sullivanian parallels, i.e., prototaxis, parataxis, and syntaxis. It will be argued that the utilisation of these categories will provide psychiatrists with the following:(1) a set of non-psychiatric criteria for clarifying the underlying principles of psychiatric claims, (2) a broader base for analysing the nature of interpersonal relations, and (3) an additional means of preserving the self-correcting character of inter-personal psychiatry as a theory.