All compounded things are impermanent. The historical Buddha taught this, over and over. These words were among the last he ever spoke.
"Compounded things" are, of course, any thing that can't be divided into parts. I understand that science tells us even the most basic "parts," chemical elements, degrade over vast periods of time.
Most of us think the impermanence of all things is an unpleasant fact we'd rather ignore. We look at the world around us, and most of it seems solid and fixed. We tend to stay in places we find comfortable and safe, and we don't want them to change. We also think we are permanent, the same person continuing from birth to death, and maybe beyond that.
In other words, we may know, intellectually, that things are impermanent, but we don't perceive things that way. And that's a problem.
Impermanence and the Four Noble Truths
In his first sermon after his enlightenment, the Buddha laid out a proposition -- the Four Noble Truths. He said that life is dukkha, a word that cannot be precisely translated into English, but is sometimes rendered "stressful," "unsatisfactory," or "suffering." Very basically, life is full of craving or "thirst" that is never satisfied. This thirst comes from ignorance of the true nature of reality.
We see ourselves as permanent beings, separate from everything else. This is the primordial ignorance and the first of the three poisons out of which arise the other two poisons, greed and hate. We go through life attaching to things, wanting them to last forever. But they don't last, and this makes us sad. We experience envy and anger and even become violent with others because we cling to a false perception of permanence.
The realization of wisdom is that this separation is an illusion, because permanence is an illusion. Even the "I" we think is so permanent is an illusion. If you are new to Buddhism, at first this may not make much sense. The idea that perceiving impermanence is the key to happiness also doesn't make much sense. It's not something that can be understood by intellect alone.
However, the Fourth Noble Truth is that through practice of the Eightfold Path we may realize and experience the truth of impermanence and be freed of the pernicious effects of the three poisons. When it's perceived that the causes of hate and greed are illusions, hate and greed -- and the misery they cause -- disappear.
Impermanence and Anatta
The Buddha taught that existence has three marks -- dukkha, anicca (impermanence), and anatta (egolessness). Anatta is also sometimes translated as "without essence" or "no self." This is the teaching that what we think of as "me," who was born one day and will die another day, is an illusion.
Yes, you are here, reading this article. But the "I" you think is permanent is really a series of thought-moments, an illusion continually generated by our bodies and senses and nervous systems. There is no permanent, fixed "me" that has always inhabited your ever-changing body.
In some schools of Buddhism, the doctrine of anatta is taken further, to the teaching of shunyata, or "emptiness." This teaching stresses that there is no intrinsic self or "thing" within a compilation of component parts, whether we are talking about a person or a car or a flower. This is an extremely difficult doctrine for most of us, so don't feel bad if this makes no sense at all. It takes time. For a little more explanation, see the Introduction to the Heart Sutra.
Impermanence and Attachment
"Attachment" is a word one hears a lot in Buddhism. Attachment in this context doesn't mean what you may think it means.
The act of attaching requires two things -- an attacher, and an object of attachment. "Attachment," then, is a natural by-product of ignorance. Because we see ourselves as a permanent thing separate from everything else, we grasp and cling to "other" things. Attachment in this sense might be defined as any mental habit that perpetuates the illusion of a permanent, separate self.
The most damaging attachment is ego attachment. Whatever we think we need to "be ourselves," whether a job title, a lifestyle, or a belief system, is an attachment. We cling to these things are are devastated when we lose them.
On top of that, we go through life wearing emotional armor to protect our egos, and that emotional armor closes us off from each other. So, in this sense, attachment comes from the illusion of a permanent, separate self, and non-attachment comes from the realization that nothing is separate.
Impermanence and Renunciation
"Renunciation" is another word one hears a lot in Buddhism. Very simply, it means to renounce whatever binds us to ignorance and suffering. It is not simply a matter of avoiding things we crave as a penance for craving. The Buddha taught that genuine renunciation requires thoroughly perceiving how we make ourselves unhappy by clinging to things we desire. When we do, renunciation naturally follows. it is an act of liberation, not a punishment.
Impermanence and Change
The seemingly fixed and solid world you see around you actually is in a state of flux. Our senses may not be able to detect moment-t0-moment change, but everything is always changing. When we fully appreciate this, we can fully appreciate our experiences without clinging to them. We can also learn to let go of old fears, disappointments, regrets. Nothing is real but this moment.
Because nothing is permanent, everything is possible. Liberation is possible. Enlightenment is possible.
Thich Nhat Hanh wrote,
"We have to nourish our insight into impermanence every day. If we do, we will live more deeply, suffer less, and enjoy life much more. Living deeply, we will touch the foundation of reality, nirvana, the world of no-birth and no-death. Touching impermanence deeply, we touch the world beyond permanence and impermanence. We touch the ground of being and see that which we have called being and nonbeing are just notions. Nothing is ever lost. Nothing is ever gained." [The Heart of the Buddha's Teaching (Parallax Press 1998), p. 124]