Are mind and consciousness reducible to events in the physical brain?

Notes drawn from Pim van Lommel, Consciousness Beyond Life: The Science of the Near-Death Experience (New York: HarperCollins, 2010) [originally published in Dutch as Eindeloos Bewustzijn]:

Consciousness, the subjective experience of an inner self, poses one of the greatest challenges to neuroscience.  Even a detailed knowledge of the brain’s workings and neural correlates of consciousness may fail to explain how or why human beings have self-aware minds.  (cited from the Australian philosopher and cognitive scientist David J. Chalmers, on 179)

It is now becoming increasingly clear that brain activity in itself cannot explain consciousness.  (179)

The hypothesis that consciousness and memory are produced and stored exclusively in the brain remains unproven.  (186)

But a connection says nothing about cause and effect.  A conscious experience can be the result of brain activity, but a brain activity can also be the result of consciousness.  (186)

It seems fair to conclude that current knowledge does not permit us to reduce consciousness only to activities and processes in the brain.  (187)

Dr. Van Lommel observes that an fMRI scan can say nothing about our feelings or the content of our thinking, and worries that fMRI results have nonetheless led some scientists to trace purported causal links between brain functions and specific mental processes.  In support of his view, he cites the Danish neuroscientist and anthropologist Andreas Roepstorff, who declares that, brain scans notwithstanding, complete and objective knowledge about the nature of the human mind is impossible.  (See pages 183-184.)

Roepstorff recalls his experience as a volunteer in an experiment.  He and other volunteers were placed in an fMRI scanner and had the soles of their feet tickled.  Sometimes they could see themselves in a mirror, being tickled; at other times, they could only feel the tickling.  The point of the experiment was to attempt to identify different ways in which the brain processes information.  At one point, though, irritated by something that the experiment leader had done and feeling rather contrary, Roepstorff decided to break the experiment’s rules.  When he merely felt himself being tickled, he thought about football or soccer.  When he could see himself being tickled, he focused instead on thinking about the funeral of his cat.

“Because I was thinking about different things,” Roepstorff reports, “the brain scans should, in theory, have shown activity in different parts of the brain.”

Given the fact that Roepstorff’s thoughts fell outside the designed scope of the experiment, the research leader should have been unable to make sense of the fMRI readings.  But he failed to notice anything different about Roepstorff’s scans; they were no different from the scans of any of the other research subjects.  Says Roepstorff himself:

Because I had decided not to do as the test leader had asked, my state of consciousness was, by definition, different from that of a subject who had followed instructions. . . .   But the test leader has no way of interpreting such a difference objectively because I did not behave noticeably different from an obedient subject.  Suppose that the measurement had been precise enough and that my brain scans had struck him as unusual; the only way he could have made sense of the difference was by asking me what went on in my head.  In which case I could either lie or tell the truth or, if I had forgotten what I had been thinking about during the scan, be useless. . . .  Thoughts are subjective.  Somebody’s thoughts can often be deduced from his or her behavior. . . .  But only the subject himself has direct access to his thoughts.  This discrepancy between the first-person perspective (subjective) and the third-person perspective (objective) presents the scientist with seemingly insurmountable methodological problems.  How can the neuroscientist obtain objective knowledge about consciousness when direct access to the brain is purely subjective, via introspection?  Consciousness is fundamentally unverifiable, and thus fails to meet scientific criteria. . . .  This evaporates the hope for completely objective knowledge about consciousness.  Sooner or later, you will have to talk to your subject, so there will always be a subjective link.  (cited on pages 183-184)

Summarizing, Dr. Van Lommel remarks that,

In fact, Roepstorff is curious to know whether in five to ten years’ time we may have to concede that we were stupid to think that we could explain us to ourselves by way of the brain.  (184)