Impermanence. A simple yet sometimes scary word. As humans, we are experts at attaching to everything around us, be they material possessions, experiences, or people we love. In fact, we are so skilled at this behavior that we often don't realize the existence of our attachments.
When Buddha spoke of suffering, he used the word dukkha, which I have mentioned before as having many possible meanings. For simplicity, I have heard to it referred to as things having an inherent 'unsatisfactoriness'. On the scale of suffering, dukkha could describe sensations ranging from slight discomfort to extreme misery.
One of the main reasons dukkha exists is that we have a problem with things being impermanent. We can see this by our inability to cope with change, and the fact that we often lament how nothing really stays the same. So what is wrong with that? Nothing, if we just acknowledge (and experience) that all things are impermanent. But something called attachment, also known as 'selfish craving' gets in the way. When we are attached, it causes us to be emotionally, mentally, physically affected when impermanence inevitably manifests itself, which ultimately makes us suffer.
There is an excellent analogy which really helps in understanding the Buddhist concept of impermanence. Imagine standing on a riverbank. The stream at the point you are standing is ever-changing in the eddies and flow of the water. Although it gives the impression of one unified flow, a myriad of factors determine that the river does not stay the same even one moment to the next.
So does this mean that nothing is real? It all seems so unstable.
If you think about it in simple terms, could the river exist if it was not constantly changing? No, it would just sit there and not be a river. The same thing with life. Life would not be what it is if we didn't breathe, our cells didn't divide, creatures weren't born and creatures didn't die. Our universe and everything in it is in a constant state of flux, and that is life. Stability can be reached by acknowledging this fact, and by practicing non-attachment. For more about impermanence from Master Thich Nhat Hanh, click here.
"Decay is inherent in all component things," declared the Buddha and his followers accepted that existence was a flux, and a continuous becoming.
May all beings be happy!