INTO THE SILENT LAND: Travels in Neuropsychology. By Paul Broks. Atlantic Books pound;16.99.

We all feel embodied, housed in flesh, bones and organs - body parts for which the mechanical and plumbing functions are now common knowledge. But what is the “it” that feels embodied, and constitutes our self? What has been lost when a loved one has “lost it”?

Oliver Sacks awakened the general reading public to the fragile contents of our skulls 30 years ago. But it’s still easy to take for granted the organ for which the term “indispensable” is unique.

When Wordsworth claimed that the “body is a portion of the soul discern’d by the five senses”, he was neglecting the sixth sense, one that isn’t remotely supernatural. It’s the sense that constantly charts the location of body parts: proprioception - perception of one’s self. You couldn’t write without it. But imagine the handicap you’d face if every joint adjustment involved a conscious decision.

Most of what the brain accomplishes is outside our awareness. The brain also happens to be the body part that eludes proprioception and all the other senses. It’s hardly surprising that the feeling of being embodied, but in some way distinct from your body, seems so compelling. Even materialists don’t deny the way things feel.

When Paul Broks declares that “values may have more to do with primitive ideas about ghosts in machines than we care to think”, he’s scoring one of the many bull’s-eyes in this book. But where should our less primitive ideas take us? As he points out, “you don’t need futuristic new technologies to expose the brute fact that there’s nothing but meat inside our heads”.

In this diverse collection of essays, Broks enters the silent land with arc lights blazing. It’s the sense that dualism seems right, but is categorically wrong, that fuels the narratives. The unique tragedies and comedies of the damaged brain provide him with engaging and varied perspectives on the nature of the self. The telling of such tales is inevitably reminiscent of Sacks - suffice to say that Sacks is a neurologist and Broks is a psychologist. Broks gives us the neuroanatomy of melancholy without fretting over the wiring diagrams.

Existentialism is back, and it’s personalised. We meet Martin, who shouts out: “I’ve been masturbating quite a lot” in response to a routine enquiry about what he’s been up to. James has a tumour called a “butterfly glioma” and a delusion that his skull is transparent. Stuart’s frontal lobe damage has excised his capacity for love. There are others for whom even small perturbations of the brain have changed everything.

It’s the provisional nature of brains, rather than of life itself, that imbues this book with melancholy, compassion and whimsy. Useful suggestions for further reading are provided in an appendix, but I wish there were titles for the chapters; they are deft and illuminating. Some enter long-term storage instantly. “To be two or not to be” plays with the practical and philosophical problems of teleportation, exploring notions of the self and the fanciful consequences of contravening the Proliferation of Persons Act. Professional philosophy this is not; but, like so many of these essays, it would provide a wonderful text for a debate.

Autobiographical ruminations on relationships abound. In what physical sense is the adult Broks, returning with his sons to a much-loved football stadium, the same as his youthful self?

This is an uncertain time for neuroscience; it’s far from clear what it will or can deliver. Broks believes “the challenge to neuroscience will be to fit the brain (a biological object) and the self (a social construct) within a common framework of understanding.” The basic conundrum is well described: “Experience is a first-person business. Science operates in the third person.”

Confronted with brains and relationships that are fragile and provisional, Broks kindles compassion and inspires. But he’s sparing with practical advice - so let me offer some. Brains are more easily protected than repaired. Check your blood pressure regularly, choose a diet full of antioxidants, abstain from boxing and wear a crash helmet when biking or skiing. What have you got to lose? The organ of your humanity.

Clive Coen is a professor of neuroscience at King’s College London