‘It is a characteristic of aging brain scientists to turn their minds to the problem of consciousness … While their ambition is admirable, the result is usually lamentable.’ Thus wrote the reliable if usually churlish psychologist Stuart Sutherland back in 1990. Susan Greenfield, a neuroscientist and brilliantly indefatigable ambassador for science, has written a book about consciousness that defies Sutherland’s rule.

She eloquently establishes the ‘hard problem’ of consciousness. How does that personal sense – what it is like to smell the scent of a rose, get the point of a joke, look at the world from a unique perspective – arise from our billions of physical neurones and