Buddhism says that all existence (including human existence) is marked by three conditions: Impermanence (Anicca), Unsatisfactoriness (Dukkha), and Non-selfhood (Anatta). We will discuss each of these, but we will do it in this order:

1. Impermanence (Annica, in Sanskrit)
2. Non-selfhood (Anatta)
3. Unsatisfactoriness (Dukkha)

1. Impermanence (Anicca)

Buddhism teaches the everything is impermanent, including our health and our lives. Everything is always changing, and each single thing is attached to myriad other things, all of which are changing.

The Buddhist concept of Impermanence (continual change) is similar to our own concepts of Continuing Creation and Evolution. But while our idea of change is positive, the Buddhist idea of change is negative. Evolution and Continuing Creation have a direction: they are constructive, progressive forces.   

Of course, it is a Shortcoming of Buddhism (and of all the other major world religions) that it arose too early to experience the power of modern science and its ability to cure illness and improve hygiene and nutrition. 

Buddhism is right when it says that all things are impermanent.  A nail may be made of iron, and in the open air it becomes iron-oxide (rust). Nevertheless, the nail is a nail for its allotted time!  It comes down to the pessimism of Buddhism versus the optimism of our Way of Continuing Creation.

Buddhists ask, “Why bother creating a nail?”
Weavers of Continuing Creation ask, “How soon we can begin forging nails?!  We want to build a house!

— J.X. Mason