I generally have negative feelings about mysticism, and anything that looks like "self-help" literature tends to put me right off. But it is good to read something different every so often, and Reflection, while it fits both categories and certainly did raise my hackles in many places, was thought provoking. Its saving graces are that Merritt doesn't think he has the answers to everything, that he isn't trying to hard sell anything, and that he writes succinctly and without being obscurantist. Reflection is his application of a particular way of looking at things to understanding his own life.
The basic idea is that our inner world and external reality are perfect reflections of one another; our conscious "outer self" may not be in concordance with the world, but our "inner self" always is. As Merritt himself points out, this is a very old concept; certainly there is a long tradition of religious and mystical ideas to the effect that coincidences aren't really coincidences and that everything is related to everything else. My basic problem with the Reflection Principle is that it is far too vague to be testable or useful as a predictive tool; all the stories which Merritt recounts as evidence for the principle have explanations constructed for them afterwards. It is also massively counterintuitive in many circumstances, and while Merrit tries to explain this away he doesn't really do a convincing job of it; there are such things as coincidences, and events do not always make any kind of sense from an individual's perspective.
Since I disagree with the basic Reflection principle, I disagree with almost all of the explanations in Merritt's stories. However I found myself rethinking many of his ideas within a more traditional causal framework as I read, and that was sort of fun.
The Reflection principle says that peoples' inner selves are linked in some mysterious way to the world around them. While I don't accept this as it stands, I do believe there is an important idea involved here. The multiplicity and complexity of the causal links between people and the world around them, links which are to a large extent unmediated by our conscious personalities, is something few people really accept; most people, most of the time, have a greatly exaggerated sense of their own rationality and their understanding of and control over themselves. And while I am not a fan of behaviourist psychology in general, when it comes to understanding oneself a behaviourist approach (looking at the world around you rather than introspecting) at least has the advantage of guaranteeing some kind of objectivity.
Most of Merritt's ideas about illness and relationships make sense viewed within a (sufficiently sophisticated) causal perspective. The importance of unconscious psychological factors in illness (and their neglect by modern medicine) is fairly broadly accepted these days, and that the functioning of relationships is often independent of conscious decisions by the participants is pretty obvious. Of course not all his examples are susceptible to this kind of analysis; as I said before there are coincidences and events that have no explanation at the level of the individual. To suggest that everyone who dies from a heart attack really wanted to die does seem to me to be preposterous.
I stick absolutely to a causal notion of responsibility. But again I agree with much of Merritt's general view, and in particular his critique of popular attitudes to responsibility (both in public law and in personal relationships). I do think his idea that everyone involved in an event is 100% responsible for it is too vague and imprecise to be really useful. It seems to me that the critical fact is that, in general, causality is not additive. In particular, if events X and Y are both necessary for event Z, and X and Y are different kinds of events/entities, then it makes no sense whatsoever to say that "X is 20% responsible and Y is 80% responsible". It is even clearer that it makes no sense when X and Y are people (ie themselves extremely complex bundles of causal links).
The one thing about Reflection that worries me most is the same thing that distresses me about other similar ways of looking at the world (for example Stoicism or certain Indian religions). This is the idea that people get what they need/deserve and just have to adjust their "wants". (The other way of wording this is to say that anyone can achieve anything if only they want it enough.) This may work reasonably well for denizens of middle America (or middle class Australia), but I find the idea of someone telling a starving sub-Saharan farmer that he is starving to death because he doesn't really want/need to live intensely abhorrent. Although the author certainly doesn't use it that way, his ideas, because of their basically individualist nature, could easily be turned to apologetics for inequality.
As you've probably gathered, Reflection wasn't really my cup of tea. Its lack of the usual paraphernalia of most New Age mysticism means it will probably not gain a great audience there. As an attempt to employ a logical approach to the illogical it will probably annoy everyone a bit.