You don’t have to peer expensively out into the farthest reaches of the cosmos to encounter the deepest mystery in the universe. Look no further than right between your own two ears.
The human mind is nowhere challenged as much as by the endeavour to understand the workings of the brain that produces it. Yet despite huge practical difficulties, the effort to comprehend how brain produces mind is perhaps more intrinsically fascinating than any other quest in science. The many other organs that make up our bodies can be pretty well understood as machines, devoted to fairly clearly defined, if complex, functions. The special challenge posed by the brain-machine is that within it there also resides a ghost: our emergent consciousness, the properties of which far exceed the sum of the internal connections and electrochemical discharges that give rise to it.
_ From the preface to The Brain (Rob DeSalle & Ian Tattersall)