Zen's Wheelhouse: No Soul, but Then What Is It?

Basui would often sit for hours stewing over this question in such a state of self-forgetfulness that he no longer knew he had a body or a mind. On one such occasion, Basui suddenly directly realized that the substratum of all things is a viable emptiness. There we go. Now we get squarely into Zen's wheelhouse. No soul, but then what is it that is seen right now, hearing these words, hearing the sound of the geese? Who am I?