Bao wrote: I don't believe that "insubstantial" means "mind". There's no need to separate this from something else, it's already separated. The importance of mind is expressed differently.
I think I wasn't clear. I did not mean that insubstantial means mind, it isn't. The student must be able to identify and differentiate between the substantial and insubstantial as a starting point. After this is achieved the internal bidirectional movement is driven by intention simultaneously. To further clarify this statement and my previous post on this, I would add that this movement is not unidirectional, with intention in one direction and emptiness in the other which is what use of "double active" as a term would suggest. Instead of this, the nature of the "driving" intention is however different in insubstantial compared to the substantial in my understanding.
I think I'll draw a line under this. There are many different interpretations of Taiji theory and we don't even know if we are on the same page. Things will just get more confusing. I just added my interpretation to double-weightedness as people keep writing about body weight distribution and footwork etc when it has nothing to do with that at all (Of this I am 100% certain).
So in brief, if there is no bidirectional internal movement going on whether on one leg, two legs, moving, not moving, then there is double-weightedness. The weightedness refers to the sinking of the chi not bodyweight or movement of mass. This whole concept is core and fundamental in Taiji and needs to be trained from day one and not further down the line in training as some people have written. Core concepts and theory should not be swept under the carpet. Internal arts require internal training as well as the external movement. If this is absent how can it be an internal art irrespective of the outward appearance. I thought it best to keep this in focus.