This world is impermanent. Everything is always changing, changing, changing, moving, moving, moving, nonstop. Even one second of our lives seems full of so much movement and change in this world that we see. But your mind — right now — is like a lens whose shutter speed is one divided by infinite time. We call that moment-mind. If you attain that mind, then this whole world's movement stops. From moment to moment you can see this world completely stop. Stop. Stop. Stop. Stop. Stop. Like the film, you perceive every frame — this moment — which is infinitely still and complete. In the frame, nothing is moving. There is no time, and nothing appears or disappears in that box. But this movie projector — your thinking mind — is always moving, around and around and around, so you experience this world as constantly moving and you constantly experience change, which is impermanence. You lose moment-mind by following your conceptual thinking, believing that it is real.
When you practice meditation for a long time, however, you can stop your mind-lens, and then you can actually experience that each moment of your life is truly infinite in time and space. This is why we call it moment-mind. It is not moving, and it is always complete. It is mind that is actually beyond time and space. Then when you see, when you hear, when you smell, when you taste, when you touch, when you think — everything, just as it is, is already complete.