An issue consistently raised in the music therapy literature is the lack of a unified understanding of its concepts as well as the reasons for its efficacy. This issue is suggested to be closely linked to problems of scientific establishment of the field. Plenty of discussions regarding the achievability, applicability and even the desirability of such a unified understanding exist in the current literature of music therapy. A question consistently remaining unexplored, however, is that under which circumstances could it even be possible for the discipline to reach a unified scientific understanding of the relationship between health, music and therapy? In the present thesis, universal law is examined as the notion which constitutes the basis of the unified body of knowledge within the scientific disciplines which have historically transcended their proto-scientific stages, and the applicability of the notion to the discipline of music therapy in order to answer its similar requirements of scientific establishment is discussed.