No argument there, but don't the Chinese say that someone "has" jin or doesn't "have" it? Since I've read that jin = li (muscular force) + qi (ki), it seems to me that it's something one has to create within oneself. Those who haven't done that work (or who don't even know of it) don't "have" jin, wouldn't you say? And since you pretty much equate jin with aiki, it seems reasonable to say someone "has" or "does not have" aiki.
Well, I understand what you're saying and I've understood it from the start. But you can't have 'aiki' without the basic jin force manifested via intention. Jin is a "specialized strength skill", not really li + qi in every case. There are a number of ways to manifest jin and some of them are pretty interesting; "aiki" is just one of those subsets.
What I'd really like is your comments on the tai chi ruler thread.
It's just an exercise, mainly for jin/qi. There are many exercises that will do the same thing. If someone has "done Tai Chi Chih for years" and done it correctly, you should be able to feel their jin/qi immediately. I.e., any exercise done correctly, particularly 'internal' exercises, should have demonstrable results. For instance, once I pushed hands with a guy in a park in London and I knew immediately that he had no jin/qi skills because they were absent. Later he asked me to watch his form and to offer some corrections for the postures. I declined. It was obvious that he'd been doing his forms wrong for years or I would have felt his jin/qi skills if he'd been doing them correctly, right? So everything he was practicing was simply wrong, but I didn't want to say such a thing to him since I'd only just met him.