I think this is an excellent reply. I would also like to add that the comment regarding the terms referred to as "hocus pocus" is not really deserving. I think for most of us here, we just have not gone into such terms deeply enough. What I see here generally is personal interpretations and explanations indicative of a lack of thorough study. On "mushin" alone, one can fill a small room with what is written on it, yet, here we limit ourselves to a few phrases, repeated over and over. Actually, in Zen, we do not really talk about "mushin' and "shin" or "kokoro" as much as is done here, we understand that this understanding comes through experience, through our training and mindfulness within daily activity. Usually, we talk in terms of "hishiryo" - literally "thought without thought" but I hate to get into a discussion of this here. I am not really qualified to discuss such terms. When we think that in martial arts, such terms regarding the mind have existed for centuries, we can begin to appreciate at what levels martial arts techniques have attained in the past.
I think that today, we can intellectualize more and we have many more branches of knowledge with which to make comparisions and conjecture, we certainly have many more fancy terms today to use in our deliberations. But one fact is that, despite, their "crude" way of explaining martial arts technique - as we seem to think today - very few today can even touch the achievements or levels of skill of those ancient masters. When I discuss this with high ranking teachers of other martial arts - they are all in agreement on this point.