For Hippocrates, Willis and Broca, this knowledge was hard won, provocative and, to many, obscure. Times have changed. Over the past 50 years the truly astonishing achievements of "neuroimaging" – the achievements, to a great extent, of physicists and engineers – have revealed the workings of the living brain in vivid detail. It is very likely indeed that we have much more to learn about the brain than we have so far discovered, but who would have guessed, in 1970, that within 50 years we would be able to glimpse the neural activity that gives rise to visual imagery, romantic love, the shivers down the spine aroused by music, the psychedelic dissolution of the self described by Aldous Huxley, the misery of depression, the recollection of our past? The thought that discoverable features of brain activity would track the contours of our experience was at best an article of faith in neuroscience when we were students in the 1970s: it has been richly vindicated. 

We have also learned that the brain is a more congenial home for the self than it seemed to be back then. The familiar analogy between brain and computer, and the emphasis in much research on the brain's response to stimulation, conceal the crucial truths that the brain is autonomously active and ceaselessly creative. Stimulation of the brain has only a marginal effect on its level of activity, which is mostly internally driven, for example by the cycle of waking and sleep. Both when we wake and when we dream, a highly organised yet highly dynamic set of networks within the brain constantly produces our world of experience, predicting our future, and taking account of our (not infrequent) errors of prediction. As one would hope, given the multiple facets of our experience, the brain revealed by contemporary neuroscience is Janus-faced, looking both within and without, at times introspective, at times directed outwards to the physical, social and cultural worlds we inhabit, to which it is fully attuned.

Recent research, and the thinking that it has inspired, does not point to any simple reductive identity of mind and brain. An influential, and representative, theory of consciousness, Giulio Tononi's theory of "integrated information", suggests that all of nature has a – sometimes – hidden potential for mentality. The Canadian philosopher Evan Thompson has underlined the way in which the precursors of minds like ours can be glimpsed in even the simplest of organisms. Other contemporary philosophers, including Edinburgh's Andy Clark, have emphasised that human minds are sustained by culture and community. The role of action and the body in forming and mediating consciousness has been a key theme in the work of the American neurologist Antonio Damasio, the Parisian psychologist Kevin O'Regan, the Berkeley philosopher Alva Noë and the Brighton-based psychiatrist Hugo Critchley. In the work of these thinkers, mind is understood to be "extended, embodied and embedded" – extended in its interactions with space and time, embodied through its dialogue with both the body and the brain, and embedded in human culture and society. 

We believe that the combined result of all these developments will be a new world view, replacing both the "porous" and the "buffered" understanding of ourselves. The earlier undifferentiated view of mind and matter, and its successor, the radically differentiated Cartesian view, will gradually give way to a more fully integrated understanding, which acknowledges both our ineradicable subjectivity and our inextricable, yet often invisible, involvement with matter. We will come to recognise that the line between mind and matter, like the line of demarcation between psychiatry and medicine, has been drawn in the wrong way and in the wrong place. We will come to understand ourselves as free within rather than from our material existence. 

Brain imaging remains a crude tool with which to probe the astonishing scale and subtlety of the human brain, but over the past 30 years it has thrown our continuous dependence on the matter of our minds into sharp relief. The cultural impact of these images is growing, just as the precarious glimpses of Jupiter's transiting moons through Galileo's clunky telescope were far more revolutionary than all the fine diagrams or subtle computations of Copernicus and Kepler during the previous "scientific" shift in our self-understanding. Where will the new vision take us?