The overall effort that Dr. Bowen made in his development of theory was to move towards a fact based science of human behavior. Therefore in this last concept, which is not yet fully developed, he noted that all events, even those that were spiritual or miraculous could be examined from a factual base. The fact that certain things, even miraculous things occur is still facts.
It is often in the explanation of who did it and why that one becomes unscientific and perspective is lost. If people are careful investigators then the function of spiritual issues, like prayer, can be measured and understood.
There will always be spiritual events that are not understood but can be looked at factually.