Re: What is Ki?
To me, it's one thing to say an experience has to be felt first hand to be truly understood, and another to say that because the experience itself is the root of knowledge that all initial guesses as to the nature of that experience are equally valid.
I know what people generally are talking about because I communicate with them using words like "ki." I have some experiences which line up, roughly, with the topic of these communications. I'm not holding myself out to tell someone else what "ki" is because, frankly, its beyond my pay grade.
Nonetheless, I understand when I hear or read something about aikido containing the word "ki" that the other person is trying to communicate something identifiable to me.
It's okay if the picture is fuzzy, because a clear picture of a fuzzy phenomenon is a fuzzy picture.
But that doesn't make the picture arbitrary, such that any fuzzy shape is equal to another in representing the reality to which it points.
You talk about someone trying to construct their own understanding of these concepts, and I understand what you're saying.
I just think that if you take a stick and ask someone if you are pointing at the moon, it makes a difference where the stick is -- roughly -- pointing.
If its an ineffable experience, then communication is pointless. Then ideas about the experience are not simply roads all leading to Rome, but impediments on the journey.
So, I don't think you can have it both ways. Either the concept of "ki" in the context of a martial art is something we can communicate about meaningfully or its not. If it is, then some approximations are better than others; if it's not, then no formulation can suffice. In neither case are all formulations inherently useful.