Nov 8, 2014 08:38 PM
(This post was last modified: Nov 8, 2014 08:41 PM by Magical Realist.)
"When we look at the world around us, we do not, as a rule, see "changes in light flux over time." We see solid objects moving and standing still in a well-defined three-dimensional space (at least, that is what we see in the most focused, central area of our vision). Nothing would be visible, however, were it not for the "light flux" entering our eyes through the pupil and flowing over the photosensitive cells lining the back of our eyeballs. Experiments have shown that when the retinal cells receive a steady, unchanging light, when the stimulus is absolutely fixed and unvarying, the cells quickly "tire." They stop sending the information our brain needs to construct the visual world we see lying in front of our eyes.[20] Thus there has to be a "flux," a movement of light over the retinal cells; otherwise, we see nothing at all. (If the sources of light do not move, the eye's own movements will keep the light moving across the cells.) "All eyes are primarily detectors of motion," R. L. Gregory points out, and the motion they detect is of light moving on the retina.[21] Only by these changing patterns of illumination can the world outside our eyes communicate with the visual processes of the brain. From that communication emerges our visual world."===http://publishing.cdlib.org/ucpressebook...nd=ucpress
