In what ways is the taijiquan form a kind of meditation and should other forms of meditation also be practised?
I think at least one part of this concept of mind extending beyond the physical limits of your body is neither esoteric and difficult nor merely a metaphor.
Consider a wholly mundane everyday activity like hitting a ball with a bat or driving a car over a small bump in the road. Imagine hitting the ball with the toe end of the bat. This will produce a jarring effect. You will feel the impact of the ball on bat directly in your hands. Similarly, a car with a very hard suspension may jar your tailbone as your drive over a sharp bump in the road. Now imagine hitting the ball right in the middle of the bat – the ball flying away sweetly. Or driving over a smooth bump with a soft suspension. What would you feel? I think on these occasions we all feel quite literally the ball make contact with the bat or the wheel climb over the bump.
This is physically impossible in the sense that our nervous systems assuredly do not magically extend into the bat as we make contact with a ball. Yet the brain interprets signals from within the folds of skin in our hands as sensations coming from the bat or car wheel. A large part of our brain is devoted to the sensations from and our motor control over our hands. The brain is working here in an interesting way but it is an everyday experience, neither magic nor metaphor.
Adhering closely to the basic principles of taijiquan, which is certainly no easy matter, should produce the ability to feel our bodies extending several feet into the ground. Likewise when weapons training or in pushing hands, practising extending our minds into the weapon and into our push hands partner is not just possible but a consequence of good practice.