Anil Seth - Being You: A Science of Consciousness

Five years ago, for the third time in my life, I ceased to exist. I was having a small operation and my brain was filling with anaesthetic. I remember sensations of blackness, detachment, and falling apart

General anaesthesia is very different from going to sleep. It has to be; if you were asleep, the surgeons knife would quickly wake you up. States of deep anaesthesia have more in common with catastrophic conditions like coma and the vegetative state, where consciousness is completely absent. Under profound anaesthesia, the brains electrical activity is almost entirely quietened something that never happens in normal life, awake or asleep. It is one of the miracles of modern medicine that anaesthesiologists can routinely alter peoples brains so that they enter and return from such deeply unconscious states. Its an act of transformation, a kind of magic: anaesthesia is the art of turning people into objects.

The objects, of course, get turned back into people. So I returned, drowsy and disoriented but definitely there. No time seemed to have passed. Waking from a deep sleep, I am sometimes confused about the time, but there is always the impression that at least some amount of time has gone by, of a continuity between my consciousness then and my consciousness now. Under general anaesthesia, things are different. I could have been under for five minutes, five hours, five years or even fifty. And under doesnt quite express it. I was simply not there, a premonition of the total oblivion of death, and, in its absence of anything, a strangely comforting one.

General anaesthesia doesnt just work on your brain, or on your mind. It works on your consciousness. By altering the delicate electrochemical balance within the neural circuitry inside your head, the basic ground state of what it is to be is temporarily abolished. In this process lies one of the greatest remaining mysteries in science, and in philosophy too.

Somehow, within each of our brains, the combined activity of billions of neurons, each one a tiny biological machine, is giving rise to a conscious experience. And not just any conscious experience, your conscious experience, right here, right now. How does this happen? Why do we experience life in the first person?

I have a childhood memory of looking in the bathroom mirror, and for the first time realising that my experience at that precise moment the experience of being me would at some point come to an end, and that I would die. I must have been about eight or nine years old, and like all early memories it is unreliable. But perhaps it was at this moment that I also realised that if my consciousness could end, then it must depend in some way on the stuff I was made of on the physical materiality of my body and my brain. It seems to me that Ive been grappling with this mystery, in one way or another, ever since.

As an undergraduate student at Cambridge University in the early nineties, a teenage romance with physics and philosophy broadened into a fascination with psychology and neuroscience, even though at the time these fields seemed to avoid, even outlaw, all mention of consciousness. My PhD research took me on a long and unexpectedly valuable detour through artificial intelligence and robotics, before a six-year stint at the Neurosciences Institute in San Diego, on the shores of the Pacific, finally delivered the chance to investigate the brain basis of consciousness directly. There, I worked with the Nobel Laureate Gerald Edelman one of the most significant figures in bringing consciousness back into view as a legitimate scientific focus.

Now, for more than a decade, Ive been Co-Director of a research centre the Sackler Centre for Consciousness Science at the University of Sussex nestled among the gentle green hills of the South Downs by the seaside city of Brighton. Our Centre brings together neuroscientists, psychologists, psychiatrists, brain imagers, virtual reality wizards and mathematicians, and philosophers, all of us trying to open new windows onto the brain basis of conscious experience.

Whether youre a scientist or not, consciousness is a mystery that matters. For each of us, our conscious experience is all there is. Without it there is nothing at all: no world, no self, no interior and no exterior.

Imagine that a future version of me, perhaps not so far away, offers you the deal of a lifetime. I can replace your brain with a machine that is its equal in every way, so that from the outside, nobody could tell the difference. This new machine has many advantages it is immune to decay, and perhaps it will allow you to live forever.