Conversations on Consciousness

Biology 202
2006 Book Commentaries
On Serendip

Conversations on Consciousness

Astra Bryant

The popular science book I choose to read, Conversations on Consciousness is a collection of short interviews that discuss the current state of the study of consciousness. Over the course of several years, Dr. Susan Blackmore (Senior Lecturer in Psychology at the University of the West of England) met privately with 21 neurobiologists and psychologists, and asked them all the same question: What is the problem of consciousness. Each interview is both an independent discussion of personal views on consciousness, and a survey of the multiple theories that have been proposed to explain human consciousness. Some of these theories are similar, many are contradictory, and a few are incredibly unique. The scientists interviewed, in alphabetical order were: Bernard Baars, Ned Block, David Chalmers, Patricia and Paul Churchland, Francis Crick, Daniel Dennett, Susan Greenfield, Richard Gregory, Stuart Hameroff, Christof Koch, Stephen LaBerge, Thomas Metzinger, Kevin O'Regan, Roger Penrose, V.S. Ramachandran, John Searle, Petra Stoerig, Francisco Varela, Max Velmans, and Daniel Wegner. With so many distinct interviews included, a complete listing of every topic mentioned in each interview would be far too lengthy to include - but such a list would include theories that describe consciousness as a spotlight in a crowded theater, a neurocomputational weapon, an expression of open-ended symbol manipulation occurring in the brain, a unified field modified by perception, a solution to the need to biologically distinguish self from non-self, and a quantum effect.(1)

With 21 interviews, each one introducing at least one new theory of consciousness, Conversations on Consciousness is filled with many fascinating topics that warrant discussion. However, during my reading, two particular theories caught my attention. The first of these is not so much a theory of consciousness, as a new way of looking at the problem of consciousness. In 1994, David Chalmers clarified the discussion of consciousness by offering a definition of what actually needed to be explained. In his interview, Chalmers again explains and elaborates on his definition of the problem of consciousness as being comprised of an easy problem, and a hard problem.

Sue: You talked earlier about the 'easy problems' and the 'hard problem', and this distinction is probably what you are most famous for. In fact, everyone now seems to start any discussion of consciousness with an account of the 'hard problem'. Can you tell me how you came to categorize it that way?

Dave: I never thought of this as a terribly profound distinction to make. I thought I was just stating the obvious. I gave a paper at the first Tucson conference on consciousness, back in '94, and early in the conference I got up and wanted to say some substantive things about consciousness. So I thought, 'OK, I'll start by stating the obvious - what need to be explained is behavior (those are the easy problems), and subjective experience (that's the hard problem).' (2)

Before reading Conversations on Consciousness, I had no introduction to the various theories of consciousness - every theory proposed in this book was a brand new idea to me. During my introduction to consciousness as a biological problem, I believe that Chalmers' distinction was the most basically insightful theory I read. Although in hindsight, the need for such a distinction is obvious, before reading Chalmers' interview, the series of problems I thought could be explained together included topics that are both easy and hard problems. Chalmers' definition allowed me to clearly distinguish issues that could be discussed without necessarily involving the complicated issue of subjectivity. I think that when discussing consciousness, it is crucial to strictly define the boundaries of your discussion - without them, explanations can become too complex in an attempt to cover al the symptoms of conscious behavior. Chalmers offers an eloquent clarification of an intrinsically complicated subject. Like most, if not all of the specific theories mentioned in Conversations on Consciousness, our in-class discussions did not mention by name Chalmers' easy/hard distinction. While discussing the grand scheme of neurobiology, divisions were avoided - our class made deliberate attempts towards formulating a united theory of the workings of the nervous system (e.g. the box within a box series of diagrams). However, discussions of the smaller components of the nervous system were approached in a manner reminiscent of Chalmers' distinction. Much of class time involved the explanation of specific biological behaviors (e.g. movement, vision, and speech). But also discussed were harder biological problems (e.g. sleepwalking and the I-function). But while the I-function was discussed in depth, with careful distinctions made between behaviors and the I-function (e.g. Christopher Reeve), we never discussed the biology behind the presence of the I-fuction - or the presence of the subjective experiences we happily defined (e.g. vision, hearing). Many times we skirted these discussions, but we never openly entered into a discussion.

The other topic that caught my attention, I must mention simply because of its controversial nature: the quantum theory of consciousness. Roger Penrose originally proposed this theory in a book entitled The Emperor's New Mind. The theory states that consciousness is intrinsically a non-computational phenomenon - that the ability to have conscious understanding requires more than mere computations mechanics (no matter how complex the computations are). While this argument could lead towards dualism, Penrose instead concluded that the ingredient missing from our largely computational vision of how the nervous system works, involves quantum mechanics. During his interview, Penrose explain how he arrived at quantum mechanics for the solution to consciousness.

Roger: I'm saying that the Gödel argument tells us that we are not simply computational entities; that out understanding is something outside computation. It doesn't tell us it's something unphysical, but there's a crucial thing that's missing, which has to do with quantum mechanics. Mine is a version of the Sherlock Holmes argument, which I admit is a weak argument - that to say once you've eliminated everything else, then what remains must be the truth, no matter how improbably. Quantum mechanics is the most obvious place where we don't know enough about physics. Where do you see non-computability in physics? You don't seem to see it anywhere else. So this, therefore, is presumably where it is. (2)

Also interviewed was Stuart Hameroff, who has collaborated with Penrose on the quantum theory. Hameroff took Penrose's idea, and located the quantum events within the microtubules of the brain's neurons.

Stuart: ... I had been studying the computational capabilities of protein structures called microtubules which make up the internal scaffolding within nerve cells. It seemed that microtubules were excellent candidates for quantum computation, that quantum computing might be happening inside nerve cells where they could be isolated. I also knew from my study on anesthesia that the molecular mechanisms by which anesthetic gas molecules erase consciousness involves only quantum mechanical interactions with certain proteins in the brain. So it was reasonable to believe that consciousness involved quantum processes and that microtubules might be quantum computers. (2)

In my opinion, this theory surpasses even the theories involving first-person reported lucid dreaming in its use of creative biological reasoning. In Conversations on Consciousness, many scientists broached the idea that consciousness is a fundamental principle of the universe (a theory that I am quite partial to, provided that sufficient evidence can be provided). But their ideas depend on measuring consciousness (e.g. humans have more consciousness than squirrels - just as humans have more mass - and theoretically we can measure this). And, as these scientists admit, there is currently no soundly quantifiable way to measure consciousness - a problem which a few scientists are working towards solving. But the quantum theory of consciousness embraces science's current inability to quantify consciousness. The proposal that our inability to solve this one problem directly connects to our inability to solve another problem is extraordinary, and somewhat audacious, as is the reclassification of microtubules from cellular support to quantum computers. After reading Hameroff's interview, I became fascinated with this theory, simply because of its outrageous logical progression. I was therefore thrilled when, several interviews later, Penrose also discussed this extraordinary theory. The quantum consciousness theory, with its current lack of supporting evidence, remains the outlandish companion to more conventional theories (e.g. emergence). But because of its sheer variety, and distinct dissimilarity to any topic discussed in class, this theory was the most memorable, and enjoyable, topic in Conversations on Consciousness.

Many other topics were discussed during the interviews, including several on dream states and the first-person method that I found too unquantifiable for my tastes. However, all these topics served as a thorough introduction to the many methods currently being used in the examination of consciousness. Conversations on Consciousness is not a typical popular science book – its topic is less specific than many of its fellows', and it is not interested in popularizing the science for the reader's benefit. The topics of most popular science books require thorough background knowledge of biology. But because these books are written to make the science accessible for a general audience, the author must teach his audience the background science they need, before he is able to make his point. Given the vast complexity of biology, these explanations may last chapters, and are frequently tediously long. But Conversations on Consciousness does not have an 'Introductory Biology for the Masses' section. As a collection of interviews, it is not one scientist's lecture to the general public. It is a series of private conversations on which the public is allowed to eavesdrop. The interviewee does not need to spend an hour explaining how neurons function – as a holder of degrees is psychology, physiology and parapsychology, Susan Blackmore (the interviewer) already knows the basic biology, and no explanations are added for the benefit of the reader. This might make the book less comprehensible for the person who knows nothing of neurobiology - without grounding in anatomical structures, the topic of consciousness can easily become a purely philosophical discussion. But I was grateful to be reading a book that did not pander to a lower denominator. Conversations on Consciousness assumes you are an informed reader - if you are not, you are left on your own to become informed (although the included glossary can be quite helpful). This was a welcome challenge, and several times I had to engage in extra research to understand the basic concepts being casually discussed.

In the end, Conversations on Consciousness gave me a unified view of the beliefs of the scientific community: a view that helped me place in context the principles I learned in class. Many of the classical neurological puzzles discussed (e.g. the Cartesian theater, the philosophers zombie, the China room) were relevant to the course, but were never actively discussed in class. Reading Conversations on Consciousness allowed me to see when the discussions of the class closely paralleled classical debates. But we were never prompted into open discussions of these debates. On one hand, this allowed us to find out own meaning given the data presented. But on the other hand, I feel that the lack of connectivity made the class discussions seem more trivial. I feel it would have enriched the discussions if those involved had been aware of the rich history of debate - and the current discussions - that we were continuing. For example, our discussion of human behavior independent of the I-function could have been enriched with knowledge of the ongoing discussion of the philosopher's zombie. Our discussion of the location of the I-function could have similarity benefited from the inclusion of the arguments for and against the Cartesian theater. In my opinion, knowledge of how what we wondered fits into the overall study of neurobiology, would have aided in our quest to contribute to the scientific community. Indeed, how could we try to contribute without informed knowledge of what those around us - the eminent scientists of the field – have already contributed? Especially given that their thoughts so closely mirrored our own. In biology, the community is a resource that should not be ignored. One person, or a group of people, working towards a theory, will always benefit by the addition of one more thinker with his own individual theory. The creation of an uninfluenced opinion is important, but so too is the inclusion of the broader community into the deliberations. In reading Conversations on Consciousness, I learned what theories are being discussed, and was able to begin to formulate my own opinions based both on my own observations and on the theories of those who worked on the problem of consciousness before me.

1) Note: Authors of mentioned theories, in order: Bernard Baars, Thomas Metzinger, V.S. Ramachandran, John Searle, Petra Stoerig, and Roger Penrose.

2) Blackmore, Susan. Conversations on Consciousness: What the Best Minds Think About the Brain, Free Will, and What It Means To Be Human. Oxford: Oxford University Press, 2006.