I have found another Edge answer that is very interesting (here). Donald Hoffman, author of Visual Intelligence, describes a metaphor for sensory qualia – a computer desktop.
Our perceptions are neither true nor false. Instead, our perceptions of space and time and objects, the fragrance of a rose, the tartness of a lemon, are all a part of our “sensory desktop,” which functions much like a computer desktop.
I have encountered people who judge our senses by how accurate they are. They are not happy with the lack of a one-to-one mapping between wave length of light and the perception of colour. The illusions that fool us are treated as mistakes. This all is interpreted as sloppiness in biological systems. But really, the purpose of our perceptions is not accuracy but usefulness.
Graphical desktops for personal computers have existed for about three decades. Yet they are now such an integral part of daily life that we might easily overlook a useful concept that they embody. A graphical desktop is a guide to adaptive behavior. Computers are notoriously complex devices, more complex than most of us care to learn. The colors, shapes and locations of icons on a desktop shield us from the computer’s complexity, and yet they allow us to harness its power by appropriately informing our behaviors, such as mouse movements and button clicks, that open, delete and otherwise manipulate files. In this way, a graphical desktop is a guide to adaptive behavior.
Graphical desktops thus make it easier to grasp the nontrivial difference between utility and truth. Utility drives evolution by natural selection. Grasping the distinction between utility and truth is therefore critical to understanding a major force that shapes our bodies, minds and sensory experiences.
… We must take our sensory experiences seriously, but not literally. This is one place where the concept of a sensory desktop is helpful. We take the icons on a graphical desktop seriously; we won’t, for instance, carelessly drag an icon to the trash, for fear of losing a valuable file. But we don’t take the colors, shapes or locations of the icons literally. They are not there to resemble the truth. They are there to facilitate useful behaviors.
This is useful to keep in mind then thinking about just how personal our personal conscious experience is. Of course we know that we can’t actually know whether your red is the same as my red. But we know that we have a map of our retinas in our thalamus and another in the cortex at the back of our heads. There may be others too. These maps are linked with nerves so that the same points on the maps communicate with one another. A place on the retina has a corresponding place in the thalamus map and the cortex map. This is accomplished by a combination of genetically produced developmental chemicals and ordinary experiences of the world environment. There is no reason for either identical or for significantly different results from this developmental program. Similarly we have the same chemicals in our retina to respond to colours etc. So the answer to whether your red is the same as mine is probably – not identical but extremely similar. Further, it hardly matters because the reason for the red or any other shade is to inform and guide our behaviour – the system has evolved to give us ‘adaptive behaviour’. Qualia have evolved to contrast what needs to be separated, to notice what needs to be noticed, to be attracted or alarmed as appropriate and they seem to do a good job of it.