The essence of our experience is change. Change is incessant. Moment by moment life flows by and it is never the same. Perpetual alteration is the essence of the perceptual universe. A thought springs up in your head and half a second later, it is gone. In comes another one, and that is gone too. A sound strikes your ears and then silence. Open your eyes and the world pours in, blink and it is gone. People come into your life and they leave again. Friends go, relatives die. Your fortunes go up and they go down. Sometimes you win and just as often you lose. It is incessant: change, change, change. No two moments ever the same.
– Henepola Gunaratana, Mindfulness in Plain English
Now, allow me to quote from a recent scientific abstract concerning fixational eye movements:
Your eyes continually move even while we fix our gaze on an object. Although these fixational eye movements have a magnitude that should make them visible to us, we are unaware of them. If fixational eye movements are counteracted, our visual perception fades completely as a result of neural adaptation. So, our visual system has a built-in paradox — we must fix our gaze to inspect the minute details of our world, but if we were to fixate perfectly, the entire world would fade from view.
Food for thought.
Martinez-Conde, S., Macknik, S. L., & Hubel, D. H. (2004). The role of fixational eye movements in visual perception. Nat Rev Neurosci, 5(3), 229-240.