Progress is a mix of disciplines

I have just returned from Mexico City. Notwithstanding the pollution, the trip was, metaphorically, a breath of scientific fresh air. One of the premier centres for graduate science education, the Center for Research and Advanced Studies of the National Polytechnic Institute (CINVESTAV) had been searching for a way to celebrate its 35 years in existence: the solution was to host a mini-conference lasting half a day. The problem was to select a theme. Given that all branches of science are taught and researched here, a conventional type of scientific presentation would not do: three-quarters of the audience would be unable to keep up. What single topic would capture everyone's imagination? Consciousness of course.

So there we were, an unlikely trio of speakers: Stuart Hammeroff, who together with mathematician Roger Penrose, has attracted both applause and complaint in applying quantum theory to understanding consciousness; David Chalmers, a philosopher of mind; and in the neuroscience corner, me. Happily, the differences in our disciplines meant that we were freed from the usual distractions of methodology, anomalies in the literature, controversies and the forensic examination of each other's data that dog most meetings of scientific minds. Unlike more conventional scientific gatherings, we were in agreement on the basic problem - and as problems go this one has to be about the most basic one left to science: how the water of hum-drum events in the brain could be converted to the wine of consciousness.

Did we get anywhere? Of course not - not in solving the water-wine issue. But our approaches were not that discordant: Hammeroff and Penrose's vision was of tiny quantum events within minuscule compartments in brain cells could co-exist within large, mercurial congresses of these same cells, that my own background prompts me to favour as the correlate of consciousness. Similarly, this cerebral scenario could easily offer the conditions for the realisation of Chalmers' idea - that consciousness is a fundamental feature of life.

Perhaps more to the point was how the question could so accommodate such different disciplines. And here is the moral of the tale: seemingly by coincidence, none of us was 100 per cent what we, at first, might have seemed to someone walking in off the street. Hammeroff started as, and still is, a clinically qualified anaesthetist; Chalmers was originally a mathematician who switched to philosophy, while way back in my A level incarnation, I did not step inside a lab once, since I had chosen classics and maths. All of us then were used to, nay comfortable with, sitting on fences between disciplines. Perhaps that was why, I mused, the issue of consciousness pulled us like a magnet. Perhaps we were not only comfortable, but most challenged when trying to bridge disciplines.

The Nobel laureate, Linus Pauling, made a formidable contribution to chemistry when he used the principles of physics to elucidate the nature of the chemical bond. In a similar vein, and winning similar recognition in the form of the Nobel prize, Gerald Edelman, described how the principles of Darwinian natural selection could be applied to the immune system. And surely, to understand consciousness, at its deepest level, it is this kind of discipline-transcending theme that is needed. It will have to be a principle or a process that is more than the province of the mathematician, the neuroscientists, or the physicists. We have to think of an approach, or imagine a process, that can be multilingual, describable in terms that are not constrained by a single discipline. We may well be still in the dark ages of understanding mental processes, analogous to the times when people agonised in vain over how to turn base metals into gold. The big difference is that we know that the conversion can and does take place within our brains every waking moment. The Mexicans chose well.

! Susan Greenfield is a neuroscientist at the University of Oxford, and Gresham Professor of Physic, London