It has taken me a long time to review this rather slender volume – to get my head around it, to follow the thread. The book emerged from a symposium which aimed to answer this question: When an individual's personality changes radically, as a consequence of either disease or intervention, should they still be treated as the same person?

The book is composed of three parts: ‘Foundations’, ‘Philosophers hold forth’ and ‘Neuroscientists push back’. There are some distinguished names heading the individual chapters. But it is easy to get lost very early on. The first chapter on foundations has more question marks than it provides answers: its fifteen pages of text are followed by seven-and-a-half pages of footnotes.

The chapter on neurobiology refers to anatomical ‘modules’ and ‘centres’, indeed even a ‘narrative centre’ in the brain: expressions perhaps used to help the philosophers, but of no help to a neuroscientist. Four case studies are then given (Alzheimer's disease, frontotemporal dementia, deep brain stimulation and steroid psychosis). Based on real-life case histories, these are a refreshing release from the main philosopher's stone, those science fictions referred to as thought experiments. It is around these case studies that the later chapters revolve.

Further in the book, we are introduced to the idea of forensic identity, concerning moral responsibility and entitlement; the importance of personal narratives; intentionality, and the rational agent – which may not be quite so rational after all. With the neuroscience push-back, DSM–IV somehow manages to get in, along with Gazzaniga's own ‘fictional self’, endowed with an interpreter firmly seated in the left hemisphere.

I am unconvinced that this symposium has produced the intended goods, although it may have been livelier in the presence of real selves. But in the last hurrah we are told that scientists should not attempt to discover philosophical truths.