Impermanence means something that is constantly changing. All phenomena and all existence in this world keep changing. It is a Buddhist teaching that everything in this world is constantly changing and never remains the same. This must be one of those phenomena that everyone knows about, yet no one knows about. If everyone knew about the impermanence of all things, they would not become attached to things and would live in peace, but since no one knows this, they become attached to things that change, and suffer.

Change means movement. Movement is the coexistence of existence and non-existence. Something that exists and yet does not exist at the same time becomes movement. If it merely exists, it would be still. It is because of the phenomenon of non-existence that it becomes motion.

The coexistence of existence and non-existence is a contradiction. Therefore, this world, where everything changes, is made up of contradictions. The Japanese translation of the Pali language, annicia, meaning shogyo mujo or impermanence, is a contradiction. In the Mahayana sutras, this truth seems to be expressed with the word "emptiness."

What should be there is missing (existence is emptiness) and what should be missing is there (emptiness is existence), whose continuity is movement and change. If we focus on the "existence," it means that all things are impermanent. If we focus on the "missing," it becomes "emptiness." If we express it from the perspective of "human heart," it means that all things would become "suffering."

At the root of suffering is the contradiction that humans must live even though they will inevitably die someday. It is quite natural that everyone has a question: why live? It is because of this kind of "suffering" that people seek pleasure. Pleasure is an unconscious escape from this suffering, but there is no escaping from the truth of human existence. The best we can do is deceive ourselves. The best choice, neither to escape nor to deceive yourself, is to wake up.

We all think of ourselves as our body and mind. Satipatthana Sutta teaches that the body is just the body, that the mind is just the mind, and the body and mind are not mine, not I, not self, but just phenomena. To wake up is to know that the body and mind are not me, which means to wake up from the dream world of this world, where the body and mind struggle. This is truly liberation from suffering.