We are not humans, immortals, or demons. We do not belong to all things in the world. Heaven and earth will kill us, and nothing will happen. Clouds are invisible and unintentional, and can connect to all things. Immortals, demons, and humans all have causes and effects to follow. Clouds float in the sky, even if the sky and the earth collapse and all living beings are in ruins, what does the cloud have to do with it?