Every culture has its shamans, oracles and priests who act as intermediaries between the known and the unknown, the seen and the unseen. In secular societies that role is increasingly being filled by scientists working at the frontiers of human understanding. Thanks to the mind-boggling obscurity of quantum theory many of these are physicists—Carlo Rovelli is only the latest to have achieved almost prophetic status.

However, even physicists are denied access to the holiest of holies: human consciousness. The anointed guardians of this sacred space are neuroscientists. Almost everyone now knows that the brain is the organ of thought and feeling, making those who study it the closest people we have to experts on the human soul.

This generates both awe and fear. Would they pluck out the heart of our mystery? Would they sound us from our lowest notes to the top of our compasses? How unworthy a thing they would make of humanity, reducing its noble spirit to the base corporeality of cells and electricity!

But that is precisely not what the most exalted of these high priests do. Like all the most influential religious leaders, for every mystery they solve they pose another. Their guidance takes us deeper into the human mind than ever before but their torches only illuminate a fraction of it. The more we explore anima incognita, the more evident it is just how inadequate our maps of it are.

It would be stretching the clerical analogy to suggest that neuroscience has its sacred texts. But it certainly has revered ones, read by laypeople eagerly seeking a glimpse into their own elusive essence.

The first great writer in this genre was the Russian Alexander Luria whose The Mind of a Mnemonist, published in English in 1968, inspired a young Oliver Sacks, whose own first book A…