Seen and unseen

We never see the world as our retina sees it. In fact, it would be a pretty horrible sight: a highly distorted set of light and dark pixels, blown up toward the centre of the retina, masked by blood vessels, with a massive hole at the location of the 'blind spot' where cables leave for the brain; the image would constantly blur and change as our gaze moved around. What we see, instead, is a three-dimensional scene, corrected for retinal defects, mended at the blind spot, stabilised for our eye and head movement, and massively reinterpreted based on our previous experience of similar visual scenes.  All these operations unfold unconsciously — although many of them are so complicated that they resist computer modelling. 

Consciousness and the Brain, Stanislas Dehaene, 2014

Image: Sinbad the Sailor by Paul Klee, 1928

"I felt as if I were standing on the top of a mountain"

A landscape opened up before me. I felt as if I were standing on the top of a mountain, gazing out over a plain, covered by long, meandering rivers. On the horizon, more mountains rose up, between them there were valleys and one of the valleys was covered by an enormous white glacier. Everything gleamed and glittered. It was as if I had been transported to another world, another part of the universe. One river was purple, the others were dark red, and the landscape they coursed through was full of unfamiliar colours. But it was the glacier that held my gaze the longest. It lay like a plateau above the valley, sharply white, like mountain snow on a sunny day. Suddenly a wave of red rose up and washed across the white surface. I had never seen anything quite as beautiful, and when I straightened up and moved aside to make room for the doctor, for a moment my eyes were glazed with tears.

Karl Ove Knausgaard


Image: Sustina Glacier, Alaska. NASA Goddard Space Flight Center via Adventures in Geology