 It may seem that this topic has drifted from metaphysics into ethics, but human actions are not different in kind from the movements of other things in the world, and human motivation expresses the tendency toward growth inherent in the very nature of existence. The use of xing and ziran in relation to motivation differs from the concerns around free will in almost every way, but both arise as ways of explaining how human choices relate to the forces driving change in the rest of the natural world, or even how human choices relate to the very nature of being. In this way, both issues unite metaphysics and ethics.