Re: Desperate to rehabilitate ki
Mmm. Excellent thread and well phrased questions. I suppose to avoid answering I would say that everything we think of is really a 'model' of reality. Best mechanical advantage (e.g. physics) is a model which has seemed quite succesful.
Martial arts incorporate psychological and physical aspects (e.g. if you grab someone hard they tend to tense themselves - but not directly because of the power you exert).
I see ki as a model of reality, just as physics is. In many ways it is very succesful and combines aspects of psychology and physics and physiology very well. Is it real? If the model works, it is real until we find aspects of our model that don't work, then we have to rethink our model.
From personal experience I would say ki is a useful model. However, I don't believe telling someone 'use your ki' has any benefit if they have little understanding what you mean. You may as well say 'use your kireshne'. In your example, I would say relaxation is part of the mechanical advantage (using the weight of your body and limbs without excessive use of antagonistic muscles), although the 'ki' model can be easier to visualise than the combined physical/physiological/pschological model.