The brain is wider than the sky,
For, put them side by side.
The one the other will include
With ease, and you beside.

~ Emily Dickinson

To describe the capabilities of the human brain, one very quickly runs out of superlatives, for this little organ, weighing less than 2 percent of our body weight, is unquestionably the most extraordinary thing in the universe, the source of the rich imaginations that have powered the intellectual evolution of our species.

For all its marvels, the brain is a curiously private organ. The heart pumps, the lungs inflate and deflate, the intestines quietly ripple and gurgle, but the brain just sits there inside your skull like a prisoner that never sees the outside world, ostensibly doing nothing and giving away nothing. Nor does its ungainly structure hint that this is a venerable instrument of consciousness and the highest thinking, the source of our stunning achievements, from science and engineering to the entire spectrum of the arts. Put differently, without the brain as we know it, there would be no Newtons, no Einsteins, no Mozarts, no Picassos. Yet, the great paradox of the brain is that everything we know about the world is given to us by an organ that itself has never seen the world. As mentioned, the brain sits under your skull like a prisoner confined to a dungeon. It has never seen the blue of the sky, never felt the warmth of sunshine, never smelled the fragrance of a rose, never heard a symphony. All it does is sit in your head to receive and send electrical impulses picked up by your eyes, ears and nose, processing these signals through its huge network of neurons numbering in trillions and trillions of connections, and converting them into a vibrant three-dimensional universe of colors, shapes, smell, and sounds. And if that is not extraordinary enough, consider these non-intuitive facts: photons of light are colorless, sound waves have no sound, and scent molecules have no smell. The brain – that “prisoner” locked in darkness – does all the work of manufacturing the components that make up our senses. In short, all the richness of life is inside your head. What you see if not what the eyes see but what the brain tells you it is. Ditto with smell and sound. Your brain is you; everything else is just plumbing and scaffolding.  

Further reading:

The Body by Bill Bryson, Black Swan, 2019 (this post is adapted from a chapter in Bryson’s book).