According to the Buddha all momentary happenings go through three stages, three submoments: a moment of arising, finally a moment of perishing, and between the two "a transformation of that which stands". This intermediate stage means that even in the brief moment that a thing exists it isn't static but changing, a process, a flux of becoming. The stable entities that we see are really bundles of events, "packages" of momentary flashings strung together by laws of conditionality.
 |
The Buddha's teaching of radical impermanence applies to all formations without exception, especially to the five aggregates of clinging, to our own personality. To the eye of insight our entire being dissloves into a compound of conditioned factors.
First take the aggregate of material form. The body is made up of minute groups of material phenomena which are themselves actually streams of events arising and passing away with incredible speed. The change takes so fast that the eye and the mind cannot register it. If we twirl a glowing stick in the dark, the eye fuses the moving points of light into the shape of a circle, so it appears to be a solid circle of light. In the same way all material form is fused together into the appearance of a solid body, but the solid body is only a mental representation and not a reality.
The same process of change applies to the mind. The mind is a composite of four mental aggregates - feelings, perceptions, mental formations and consciousness. These are all in process, streams of events arising and perishing countless times each second. In every moment there is a new feeling arising and passing, a new perception, new mental formations and new consciousness. They appear to form a stable lasting mind. But this is only an appearance caused by the continuity of the process.