Active receptivity is what we're aiming to cultivate in zazen, and in the rest of our practice. Despite the emphasis on what we're NOT doing in zazen, it should lively and energetic activity, not passive. Think of putting aside your physical and mental activities in order to become incredibly quiet and receptive. Shhh! What's that? It's like we're surrounded by the music of a whole symphony that we usually can't even hear because of our internal and external chatter.