In zen it is said if you try to grasp movement you are met with stillness; when you attempt to grasp stillness you are met with movement, like a fish under water creating a ripple on the surface...very elusive indeed. Therefore, we counter stillness and movement or pushing and pulling with a simple strategy of pull when they push and push when they pull; this is the way to higher skillfulness. Karate does not just involve physical techniques; in fact if you were to break up Karate into three parts, two of these parts are non-physical. We call this the triad in training with those parts being austere training, protracted meditation and philosophical assimilation. Sharpening the mind’s ability to deal with the myriad of circumstances and situations that life throws at it is a great personal attribute.
It’s actually that space between hard and soft, fast and slow, strong and weak ie: dealing with the changes in the attack or adversity is what the practitioner looks to master. The objective, like the old masters, was to not get stuck at either end but to utilize both stillness AND movement in the end where most appropriate. This skill is the sword edge of the mind and is developed via hard training, deep meditation, along with the philosophical understanding; this obviously takes time but in time using this approach all things will become clear.
This is why they say: Zen, Ken, Ishoa - mind, fist and meditation are one.