Anicca, impermanence, underlies all Buddhist thought and practice and is the foundation of Buddhist understanding of reality.

For many centuries most Western people had thought that the universe was a permanent thing, put into place by a Creator God, with the earth at its center. They reasoned that such a complex system could not come into existence except through the creation of a superior intelligence. They named that superior intelligence God and declared his permanence. They believed that humankind reflected the image of God and contained also an immortal essence, which they termed soul. So, while things around them might change, they reasoned, at least they were assured of permanence, an eternal existence after death if they lived in accordance with God's will.

In India twenty-five centuries ago, Siddhartha Gautama, the Buddha, proclaimed that there is no permanence anywhere. In his enlightenment experience he witnessed the arising and disappearing of entire universe systems. He saw very clearly that all things are impermanent, that they arise, mature and pass away. He recognized that all things are comprised of conditioned states and that there is no permanent essence to anything. He also realized that the arising and disappearing of states of existence occurred because of various conditions. Should any condition change, the object changed or disappeared.

Even those things which appear to be permanent and unchanging also are in a constant state of change. The mountains appear to be permanent and unchanging, but their very existence is the result of tectonic forces within the crust and mantle of the earth. Volcanoes, inactive for many centuries come alive and new ones pop into existence. Earthquakes build mountain ranges. Ocean becomes land and land becomes ocean. These changes never cease. All matter itself is alive with constant change. Its very nature is a mass of constantly moving energy. Rocks may appear to be inert objects, but in actuality, their very structure is one of constant movement.

The Buddha taught that all conditioned things are impermanent and constantly changing and that they have no permanent essence. He explained that while we may think of ourselves as single objects of existence, in fact humans are made up of a collection of five conditioned, impermanent states: body (rupa), sense contacts and sensations (vedana), perceptions and conceptions (samjna), volitional actions and karmic tendencies (samskaras) and basic consciousness (vijñana). These collections (skandhas) of things are the true nature of the person and they are constantly changing. The body grows old, becomes ill and dies. Sense contacts lead to perception and conception and these are constantly changing. Our karmic activities never cease and underlying all these is the basal consciousness, which at death also disappears with all of the other samskaras.

The Buddha explained that we should not become too attached to our bodies and their sensual experiences and thoughts that arise from them, because the attachment to our bodies and to life causes us great dukkha, suffering and misery. Sense contact brings us sense experiences which we then term as desirable or undesirable. From this judgment arises the desire to re-experience similar sensual experiences, which lead directly to attachment. This attachment then leads to a great thirst or craving for the experience. Soon we are entrapped in the need to continue such experiences, for we feel we need or want them. But all experience is very momentary. Hardly have we grasped onto one, when it disappears and a new attraction grabs our minds. Soon we are enmeshed in a great, complex web of desire, all of which is very transitory, and thus unsatisfactory.

The Buddha stated that for us to become free from the constant round of rebirth and suffering, we would need to realize the changing nature of things in its true perspective, so that we could free ourselves from the need for certain experiences, attachment to self and to the illusion of permanence.

One of the major causes of dukkha is our puny attempts to make impermanent things permanent. We want to amass and hold on to things which please our ego concepts. We strive to hold on to youth, to wealth, to fame, to romance. All of these experiences are fleeting. They arise, mature and disintegrate. It is not change itself which causes the greatest pain, it is our resistance to this change that causes the real dukkha. The Buddha again and again explained: "Impermanent indeed are all conditioned things; they are of the nature of arising and passing away. Having come into being, they cease to exist. Hence their pacification is tranquility."

He urged his disciples to truly understand the ultimate nature of all things, that is their impermanence. He had his disciples meditate upon the disintegration of things, including their own bodies, in order to try to break their inordinate clinging to objects of all kinds: physical, vocal or mental.

Once the individual truly sees that things cannot be grasped for more than a few moments, then these unhealthy attachments and aversions can be given up and the practitioner can be freed from the enslavement he has produced for himself.