At this point it is important to realize that Grof’s criticism of Wilber’s theory is just as relevant to the Integrated Experiential Coaching Model, namely:

… it is not sufficient to integrate material from many different ancient and modern sources into a system that shows inner logical cohesion. While logical consistency certainly is a valuable prerequisite, a viable theory has to have an additional property that is equally, if not more, important. It is generally accepted among scientists that a system of propositions is an acceptable theory if, and only if, its conclusions are in agreement with observable facts (Frank, 1957). … For this reason, evaluating his ideas in the light of actual experiences and observations from … research seems particularly important and necessary (Grof, 1998:88–89).