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THINKING ABOUT THINKING

Review by Jack Cohen

Brainchildren: Essays on Designing Minds
BY DANIEL C. DENNETT
MIT Press, Cambridge, Mass., 1998 ($40; paperbound, $20)

Dan Dennett is a big man. He takes up a lot of space in the physical,
intellectual and academic worlds. I have never heard anyone wonder
that he is the Distinguished Professor of Arts and Sciences at Tufts
University; he lives up to it. He produces books like Kinds of Minds
and Consciousness Explained. He has already had a special issue of
Philosophical Topics devoted to his work and a collection called
Dennett and His Critics from Oxford University Press. And there are
many critics; he is in no majority that I can detect, yet everyone
professionally concerned with minds takes notice of what he says. He
is in fact a cult figure, which is strange because the song he sings
is not a pop song but an extended aria. It requires attention, but it
rewards the reader with that most valued commodity, interest: he
changes people's minds--about minds.

I first met his thinking attached to that of Douglas Hofstadter in The
Mind's I. Hofstadter I knew as the author of the wonderful Gödel,
Escher, Bach: An Eternal Golden Braid; this chap Dennett I hadn't
heard of (bear in mind that I am an English reproductive biologist).
But I then bought his essays, Brainstorms. Essayists I enjoy. And here
was an addition to my list, with the persuasiveness of Peter Medawar,
the style of Lewis Thomas, the personal touch of Isaac Asimov.

Now he has produced this new collection, as diverse as ever but with
two major themes: consciousness in people, machines and animals; and
thinking about consciousness in people, machines and
animals--metaconsciousness? (He quotes Hofstadter: "Anything you can
do, I can do meta.") He claims the book is to make essays that
originally appeared in, for example, the journal Raritan more
accessible. One, from Poetics Today, is a nice piece on his experience
of field ethology with vervet monkeys, which should be read by all who
think that some animals, especially primates, must have minds like
ours.

In addition to these difficult-to-find essays, Dennett included some
of his better-known position statements. For example, "Real Patterns"
(from the Journal of Philosophy) asks about the transactions and
transformations that begin with regularities in visual fields, or
sounds or odors, and that result in beliefs and opinions--changes in
the structure of a mind. He believes, as most of us now do, that the
"mind" is a diverse set of tools for perceiving and thinking. (In this
regard, he devised the image of pandemonium, many
demons--computer-speak demons--offering items that compete for
attention.) Thus, the changes that occur are disparate, diverse, very
rarely affecting all of the "me." Indeed, the essay "Real
Consciousness" picks up on critics of his disbelief in such a
"unitary" consciousness.

Too many philosophers, it seems to Dennett, still want "definitions";
they want to play with counters that have defined values, even in
studies of the mind. When such philosophers play in science gardens
like physics, this works. Definitions abound: an electron is a
well-defined concept. Dennett shows in many of these writings,
especially in "Do-It-Yourself Understanding" and "Self-Portrait," that
biology isn't like that. "All mammals have mammal mothers," for
example, but it isn't an infinite regress, as these philosophers might
claim: there is a finite but indefinite history of mammals. Nearly all
biological concepts have such blurred edges, nearly all biological
processes are effective but inefficient, and we biologists work with
them without difficulty and without persnickety definitions. Biology
is like "discovered" engineering, and reverse-engineering thinking is
needed to understand the whys and wherefores of animal and human
behavior.

And too many philosophers believe in their own introspections. Dennett
uses the "frame" problem, so difficult to access by introspection, as
his demonstration of introspection's failure. When we deal with
anything, we unerringly isolate the problem, the issue, what we are
doing, from the irrelevant universe of possibilities that surrounds
it. Our robots can't do this yet, perhaps because we can't see how we
do it. Dennett's example is beautifully down-to-earth: the problem of
getting a midnight snack from the fridge. All the givens, all the
unknowns, all the assumptions--about the stickiness of the slices of
turkey for the bread, say--are very difficult to locate by
introspection; nevertheless, one "just goes and gets a sandwich."

Sifting Wheat from Chaff

Only in another piece, about programming such detail into a robot,
does this miraculous ability of our brains get exposed. Nobody knows
how we do this. All animals do it. They don't get caught up, as stupid
robots do, listing all the unproblematic things ("That tree probably
won't move, that rock probably won't move") and what might happen to
the problematic ones ("That bird might fall on my head"). Dennett
looks at R1-D1, R2-D1 and their kin--clever R2-D2, of course, has
solved this.

Like R2-D2, animals just get on with their business and exclude the
irrelevant. A simple basis for this could be that nerve cells
habituate, so that even uncomplicated creatures don't "see" trees and
rocks, and most animals have tuned-down senses, so that what excites
them is specially tuned-for and therefore probably important. Dennett
calls this decoration of the important sense impressions "salience." I
think he could usefully relate this emphasis of significant items to
his arguments about qualia. Qualia, such as "redness" and "the smell
of bacon," are decorations of the perceptions in the mind, which were
transduced from light-frequency and molecules in the air. Dennett
takes on qualia in two essays. One, about Hard Questions of
consciousness, invokes zombies, and it is a failure for me. Zombies
are imaginary people who are identical down to molecules with the rest
of us but who don't have qualia; they react to red light, but they
don't see "red," as we do, inside their heads. This imaginary exercise
somehow shows some philosophers, but not Dennett or me, that
consciousness (as qualia) is "not materially rooted."

Dennett gets very highbrow about this nonsense and invents zimboes, a
kind of improved-model zombie, and makes a lot of comparisons with
other people's models to show how silly the concept is. I didn't, and
don't, understand how zimboes help disprove anything. Zombies can
exist only in dualist universes; imagining them begs the very question
they are set up to test. (In Figments of Reality Ian Stewart and I
used the imagined "zombike" to debunk zombies: this is exactly like a
regular bicycle, down to molecules, but the back wheel doesn't go
round when you turn the pedals. A comparable argument would show, just
as stupidly, that locomotion, like consciousness, is "not materially
rooted," an ineffable hyperproperty of the system.)

Another failed essay, for me, is the final one in the book,
"Information, Technology and the Virtues of Ignorance." In it, Dennett
contends that our moral obligations to act must become overwhelming
with the increased information we all have. So, according to him,
these obligations must be limited again--as they were in the past--by
increasing our relative ignorance. This kind of thinking seems to me
to be another example of the "frame" problem: we will construct little
"relevant," framed moralities for ourselves by failure to consider
most of the world's problems, even if we do know about them.

There are some bonuses--including a wonderfully critical but
just-persuaded account of multiple-personality psychoses, written with
Nicholas Humphrey; a very positive response to the critics of Julian
Jaynes's The Origins of Consciousness in the Breakdown of the
Bicameral Mind; comments on artificial life (AL) as well as artificial
intelligence (AI)--all good-tempered, often witty.

Several of the essays tackle (and tackle very well) the issues of
animal minds and our ability to think about them in terms of our own
mind. Quotes from Moby Dick about whale vision being left-right
separate softened me up for Thomas Nagel's question about what it's
like to be a bat. Then I learn that rabbits' brains don't transfer
learning across the midline--train them with the right eye, the left
shows no response! Next I'm challenged by experiments with snakes,
which use, apparently must use, three different sensory modalities to
catch and eat prey: they hunt and strike only visually; they find the
prey only by smell (even if it is squeezed in their own coils); and
they find the head, to swallow the prey, by touch.

I am not naive in these animal-behavior matters. I've kept many kinds
of mammals: llamas, Chinese hamsters, polecats, bush babies and other
creatures, like mantis shrimps and octopuses, that show considerable
intelligence. And many snakes, big spiders, odd insects and fish,
including the intelligent cichlids. Yet Dennett tells me a story that
convinces me, about the "minds" of these creatures, which is different
from what I believed 10 years ago. He takes my attention to
places--experiments with rabbit-brain sidedness, for example--that
decorate this new view with believability. He shows me how different
minds are, even vervet monkey minds. Again he has got in among my
prejudices and changed my mind; this new book has opened new areas of
contention for me.

This man improves my universe and yours. Enjoy him.

JACK COHEN, a reproductive biologist, has positions in both the
Ecosystems Unit of the biology department and the Mathematics
Institute at Warwick University in Coventry, England.
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