When light hits the eye’s retina, special cells called photoreceptors turn the light into electrical signals. These electrical signals travel from the retina through the optic nerve to the brain, where these signals are turned  into the images we see. The relation between what we see and what we perceive and understand is never settled. People can look at the same object but view it in a completely different way. If “so many men, so many minds,” then certainly there are so many brains, and consequently so many directions from which an object is looked at.