Blog Editor

Notices

  • Copyright 2005-20012 by Adam Kolber
    All rights reserved.

« Voodoo Correlations in Social Neuroscience - the debate continues | Main | Interesting Tidbits »

Comments

Thanks to Daniel for moving this discussion into a new post - it is most appropriate (IMHO).

As a died-in-the-wool, neurobiologist, I cannot help but take the tasty bait that you have offered up. I will say that I am not steeped in Searle's arguments, so please correct any silly comments that I may make. Having put forward that disclaimer, I will proceed to make my case.

Daniel states, "I am not remotely ascribing to a notion of mentalism in which mental substances are simply floating in the ether. That's absurd; without physical brain, there is no mind. Searle's point is that a notion of subjectivity is also a requisite component of consciousness. This subjectivity is not reducible, is not categorizable in mechanistic terms, and it cannot be quantitated. Mental life is "grounded" in the brain, but is not reducible to it."

He then goes on to lambast (perhaps correctly) neuroscientists for "the tacit notions in neuroscience that eventually, we can progress to the point where scientific modalities can explain everything and account for all of our lived experiences."

I am comfortable holding open the possibility that neuroscience will not be able to reduce all mental experience to molecular, cellular, or network events (or even other categories about which we are currently entirely ignorant). But please note that I carefully said that I would hold open the possibility for such an outcome. After 30 some odd years of immersion in neuroscience, I know better than to suggest certainty for an outcome which is anything but.

My question for Daniel is simple. Why, if you ask such open-mindedness of neuroscientists (who share, in your words, a "tacit" notion, not an iron-clad rule), are you so certain that "subjectivity is not reducible, is not categorizable in mechanistic terms, and it cannot be quantitated." What if it turns out that it is reducible?

Peter,

Thanks for the comments. Since we've yet to have the pleasure of interacting much in blogospheric space or otherwise, let me be the first to tell you that I am a cheerful and committed fallibilist. In fact, I think a great many of our most serious problems in thinking about health and illness stem from a fundamental difficulty with uncertainty (The difficulty is not because interlocutors are unaware of the uncertainty, but rather in the constant attempts to eliminate the ineliminable rather than acknowledging and even harnessing the uncertainty and the implications thereof; there are, for example, many different ways of knowing, some of them even scientific, in which uncertainty and ambiguity is both accepted and even utilized in the production of knowledge).

So, if I in any way conveyed an attitude of certainty, it was accidental and totally unintended. My commitment to fallibilism and skepticism requires me to admit, quite cheerfully, that I could indeed be mistaken about subjectivity.

What if it is reducible to physical substrate?

I think there are some profound implications for that, especially in context of free will, but it nevertheless does not follow even from the premise that subjectivity is nothing but brain that the meaning of our mental experiences can be exhausted scientifically.

Searle, and many others, address these questions. For example, even if it is the case that the conscious experience of pain is reducible to neuronal firings, it is quite wrong, IMO, to suggest that that causal pathway exhausts the meaning of pain for the pain sufferer. Even if my enjoyment of Beethoven is nothing but so many synaptic firings, it does not follow that what we might like to understand about what Beethoven means to me and why it is that I enjoy Beethoven is fully explicable by reference to those synaptic firings.

What about cancer? If indeed cancer is reducible to nothing but 'growth signals' that can't be turned off -- and here you have obviously forgotten more than I will ever know about this -- it simply does not follow that what matters for people who have cancer, what it means for them, is explicable in terms of misfiring growth signals.

Moreover, even some neuroscientists acknowledge as such. Howard Fields, who is, in my view, an excellent example of an incredible scientist who is also not a reductionist, argued in a 2007 essay that what is most important in the neuroscience of pain is understanding what pain means to human beings. This is an inversion of the typical hierarchy, in which thinking about what pain means to human beings is deemed to be explicable in terms of the neuroscience of pain.

Long-winded answer, but there you go. If I am wrong about my claim, lots of profound implications follow. What does not follow is the idea that all that matters about the functions we are correlating -- love, hate, pain, etc. -- is explicable in terms of brain.

But in any case, though I freely concede I might be wrong, I happen to believe I am right. ;-)

Thanks Daniel for your answers and the interesting ongoing discussion.

Just a final thought on one aspect of Peter´s reply.

At the moment we don´t know if ultimately the subjetive realm, whatever its complexity, could be reduce to molecular, cellular and network levels of the central nervous system´s organization.

It might be reducible or it might not be reducible.

But i wonder if reductionism is not a path worth taking.

Reductionism is not elimination or simplification, is causation.

Reductionism is explaining what are the causes of complex phenomena.

Daniel: thanks for the thoughtful reply, which is much more open-minded than the seemingly dogmatic words I quoted in my eariler comment. I am happy for that.

I will take this opportunity to turn matters on their head yet again. Earlier this month, Verlyn Klinkenborg (a member of the NY Times Editorial Board, no less) had a wonderful opinion piece on heronry. I knew that I had bookmarked this item for a reason, and it turns out that this discussion is it! I recommend reading the entire post [http://www.nytimes.com/2009/01/05/opinion/05mon4.html?_r=1], but the paragraph that is most relevant is this:

"I am used to thinking of evolution doing the selecting — blind, impassive adaptation over millions of years. That is a dispassionate way of understanding behavior. But a heronry embodies a system of knowledge present in these herons, a complete, successful and highly inventive understanding of this world around them. Grasping how it came to be does not make it any less marvelous."

Verlyn's naturalist's eye and writer's ear reminds us that experiencing a sense of wonder at the complexity (or, for that matter, the simplicity) of the world is entirely compatible with understanding it. When we do both, epic questions such as the ones you pose dissolve effortlessly.

Anibal,

I have lately become aware that reductionism, which is a definite pejorative in the circles I move in, is often taken to be a badge of honor among neuroscientists in particular. First, I agree that epistemic reductionism is not inherently elimination or simplification, but disagree that this distinction is generally observed in practice. This epistemic reductionism in neuroscience consistently and generally turns into a kind of ontological reductionism, in which all that is taken to matter about the "reality" of the phenomenon under investigation is whether it can be objectified, packaged, and categorized according to scientific modalities.

But even epistemic reductionism is deeply problematic as a means of assessing scientific causation, because the behavior of nonlinear dynamical complex systems like the brain generally cannot be explained, or can be explained only poorly, through a linear, reductionist approach, which is a serious problem, in my view (many others think so in diverse fields, too, including epidemiology and population health, physics, systems biology, etc.). We're not going to get very far in understanding what phenomena in the brain are causal factors in producing behavior if we continue to insist on reducing such phenomena to discrete, individual variables isolated from the larger systems in which they are situated. Yet, unless I am very mistaken, this is what we tend to do in most kinds of scientific endeavors. I am less familiar with this tendency in neuroscience than I am in epidemiology and disease causality, in which such causal reductionism is severe and pronounced, with serious consequences, IMO.

Peter,

Again, I apologize if I came across as dogmatic. At times my vehemence and emphasis may come across as dogmatism, which I work very hard to avoid.

But my response to you is similar to what I stated to Anibal. Of course the epistemic reductionism utilized in scientific practice need not imply an ontological reductionism. But in practice, and in social and cultural representations of science, this is exactly what happens. As Charles Rosenberg once noted, there have for over a century been voices who have warned against the excesses and consequences of the excessive ontological reductionism in medicine and science, but, he states (paraphrase), "such voices have never been adequate to counter the lure of the laboratory. They still are not."

The comments to this entry are closed.