Stability is not the same as stillness. A bicycle is stable because it is moving; stood still it falls over immediately, which is a strange fact about a thing everybody calls steady.
Some of what keeps you upright works similarly. It is not a fixed position but a continuous set of small corrections — the routine kept, the person texted back, the walk taken on the day you least wanted to.
Ground is not only something you stand on. It is something you keep making contact with.