What mystifies me most is consciousness.

Not intelligence. Not memory. Not even love, though love is a magnificent puzzle.

It is the astonishing fact that there is an inside to being alive.

Light hits the retina, neurons fire, chemicals move, electrical signals race through wet tissue, and somehow there is blue. There is the smell of rain. There is embarrassment. There is longing. There is the private sensation of being you, looking out through one particular pair of eyes at a universe that existed for billions of years before you arrived.

We can describe a great deal about what the brain does. But why any of it should feel like something remains deeply strange.