1. Does thought depend on language?
We human beings may not be the most admirable species on the planet, or the most
likely to survive for another millennium, but we are without any doubt at all
the most intelligent. We are also the only species with language. What is the
relation between these two obvious facts?
Before going on to consider that question, I must pause briefly to defend my
second premise. Don’t whales and dolphins, vervet monkeys and honey bees (the
list goes on) have languages of sorts? Haven’t chimpanzees in laboratories been
taught rudimentary languages of sorts? Yes, and body language is a sort of
language, and music is the international language (sort of) and politics is a
sort of language, and the complex world of odor and olfaction is another, highly
emotionally charged language, and so on. It sometimes seems that the highest
praise we can bestow on a phenomenon we are studying is the claim that its
complexities entitle it to be called a language–of sorts. This admiration for
language–real language, the sort only we human beings use–is well-founded. The
expressive, information-encoding properties of real language are practically
limitless (in at least some dimensions), and the powers that other species
acquire in virtue of their use of proto-languages, hemi-semi-demi-languages, are
indeed similar to the powers we acquire thanks to our use of real language.
These other species do climb a few steps up the mountain on whose summit we
reside, thanks to language. Looking at the vast differences between their gains
and ours is one way of approaching the question I want to address:
How does language contribute to intelligence?
I once saw a cartoon showing two hippopotami basking in a swamp, and one was
saying to the other: “Funny–I keep thinking it’s Tuesday!” Surely no
hippopotamus could ever think the thought that it’s Tuesday. But on the other
hand, if a hippopotamus could say that it was thinking any thought, it could
probably think the thought that it was Tuesday.


What varieties of thought require language? What varieties of thought (if any)
are possible without language? These might be viewed as purely philosophical
questions, to be investigated by a systematic logical analysis of the necessary
and sufficient conditions for the occurrence of various thoughts in various
minds. And in principle such an investigation might work, but in practice it is
hopeless. Any such philosophical analysis must be guided at the outset by
reflections about what the “obvious” constraining facts about thought and
language are, and these initial intuitions turn out to be treacherous.
We watch a chimpanzee, with her soulful face, her inquisitive eyes and deft
fingers, and we very definitely get a sense of the mind within, but the more we
watch, the more our picture of her mind swims before our eyes. In some ways she
is so human, so insightful, but we soon learn (to our dismay or relief,
depending on our hopes) that in other ways, she is so dense, so uncomprehending,
so unreachably cut off from our human world. How could a chimp who so obviously
understands A fail to understand B? It sometimes seems flat impossible–as
impossible as a person who can do multiplication and division but can’t count to
ten. But is that really impossible? What about idiot savants who can play the
piano but not read music, or children with Williams Syndrome (Infantile
Hypercalcemia or IHC) who can carry on hyperfluent, apparently precocious
conversations but are so profoundly retarded they cannot clothe themselves?
Philosophical analysis by itself cannot penetrate this thicket of perplexities.
While philosophers who define their terms carefully might succeed in proving
logically that–let’s say–mathematical thoughts are impossible without
mathematical language, such a proof might be consigned to irrelevance by the
surprising discovery that mathematical intelligence does not depend on being
able to have mathematical thoughts so defined!
Consider a few simple questions about chimpanzees: could chimpanzees learn to
tend a fire–could they gather firewood, keep it dry, preserve the coals, break
the wood, keep the fire size within proper bounds? And if they couldn’t invent
these novel activities on their own, could they be trained by human beings to do
these things? I wonder. Here’s another question. Suppose you imagine something
novel–I hereby invite you to imagine a man climbing up a rope with a plastic
dustbin over his head. An easy mental task for you. Could a chimpanzee do the
same thing in her mind’s eye? I wonder. I chose the elements–man, rope,
climbing, dustbin, head–as familiar objects in the perceptual and behavioral
world of a laboratory chimp, but I wonder whether a chimp could put them
together in this novel way–even by accident, as it were. You were provoked to
perform your mental act by my verbal suggestion, and probably you often perform
similar mental acts on your own in response to verbal suggestions you give
yourself–not out loud, but definitely in words. Could it be otherwise? Could a
chimpanzee get itself to perform such a mental act without the help of verbal
suggestion? Endnote 1 I wonder.
2. “Cognitive closure”: comparing our minds with others
These are rather simple questions about chimpanzees, but neither you nor I know
the answers–yet. The answers are not impossible to acquire, but not easy
either; controlled experiments could yield the answers, which would shed light
on the role of language in turning brains into minds like ours. I think it is
very likely that every content that has so far passed through your mind and
mine, as I have been presenting this talk, is strictly off limits to
non-language-users, be they apes or dolphins, or even non-signing Deaf people.
If this is true, it is a striking fact, so striking that it reverses the burden
of proof in what otherwise would be a compelling argument: the claim, first
advanced by the linguist Noam Chomsky, and more recently defended by the
philosophers Jerry Fodor and Colin McGinn (1990), that our minds, like those of
all other species, must suffer “cognitive closure” with regard to some topics of
inquiry. Spiders can’t contemplate the concept of fishing, and birds–some of
whom are excellent at fishing–aren’t up to thinking about democracy. What is
inaccessible to the dog or the dolphin, may be readily grasped by the chimp, but
the chimp in turn will be cognitively closed to some domains we human beings
have no difficulty thinking about. Chomsky and company ask a rhetorical
question: What makes us think we are different? Aren’t there bound to be strict
limits on what Homo sapiens may conceive? This presents itself as a biological,
naturalistic argument, reminding us of our kinship with the other beasts, and
warning us not to fall into the ancient trap of thinking “how like an angel” we
human “souls,” with our “infinite” minds are.
I think that on the contrary, it is a pseudo-biological argument, one that by
ignoring the actual biological details, misdirects us away from the case that
can be made for taking one species–our species–right off the scale of
intelligence that ranks the pig above the lizard and the ant above the oyster.
Comparing our brains with bird brains or dolphin brains is almost beside the
point, because our brains are in effect joined together into a single cognitive
system that dwarfs all others. They are joined by one of the innovations that
has invaded our brains and no others: language. I am not making the foolish
claim that all our brains are knit together by language into one gigantic mind,
thinking its transnational thoughts, but rather that each individual human
brain, thanks to its communicative links, is the beneficiary of the cognitive
labors of the others in a way that gives it unprecedented powers. Naked animal
brains are no match at all for the heavily armed and outfitted brains we carry
in our heads.
A purely philosophical approach to these issues is hopeless, I have claimed. It
must be supplemented–not replaced–with researches in a variety of disciplines
ranging from cognitive psychology and neuroscience to evolutionary theory and
paleo-anthropology. I raised the question about whether chimps could learn to
tend a fire because of its close–but treacherous!–resemblance to questions
that have been discussed in the recent flood of excellent books and articles
about the evolution of the human mind (see Further Reading).
I will not attempt on this occasion to answer the big questions, but simply
explain why answers to them will hinge on answers to the questions raised–and
to some degree answered–in this literature. In the terms of the Oxford
zoologist Richard Dawkins (1976), my role today is to be a vector of memes,
attempting to infect the minds in one niche–my home discipline of
philosophy–with memes that are already flourishing in others.

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At some point in prehistory, our ancestors tamed fire; the evidence strongly
suggests that this happened hundreds of thousands of years–or even as much as a
million years (Donald, p.114)–before the advent of language, but of course
after our hominid line split away from the ancestors of modern apes such as
chimpanzees. What, if not language, gave the first fire-taming hominids the
cognitive power to master such a project? Or is fire-tending not such a big
deal? Perhaps the only reason we don’t find chimps in the wild sitting around
campfires is that their rainy habitats have never left enough tinder around to
give fire a chance to be tamed. (The neurobiologist William Calvin tells me that
Sue Savage-Rumbaugh’s pygmy chimps in Atlanta love to go on picnics in the
woods, and enjoy staring into the campfire’s flames, just as we do.)
3. Need to know vs. the commando team: two design types
If termites can create elaborate, well-ventilated cities of mud, and weaverbirds
can weave audaciously engineered hanging nests, and beavers can build dams that
take months to complete, couldn’t chimpanzees tend a simple campfire? This
rhetorical question climbs another misleading ladder of abilities. It ignores
the independently well-evidenced possibility that there are two profoundly
different ways of building dams: the way beavers do and the way we do. The
differences are not necessarily in the products, but in the control structures
within the brains that create them. A child might study a weaverbird building
its nest, and then replicate the nest herself, finding the right pieces of
grass, and weaving them in the right order, creating, by the very same series of
steps, an identical nest. A film of the two building processes occurring
side-by-side might overwhelm us with a sense that we were seeing the same
phenomenon twice, but it would be a big mistake to impute to the bird the sort
of thought processes we know or imagine to be going on in the child. There could
be very little in common between the processes going on in the child’s brain and
the bird’s brain. The bird is (apparently) endowed with a collection of
interlocking special-purpose minimalist subroutines, well-designed by evolution
according to the notorious “Need to Know Principle” of espionage: give each
agent as little information as will suffice for it to accomplish its share of
the mission.
Control systems designed under this principle can be astonishingly
successful–witness the birds’ nests, after all–whenever the environment has
enough simplicity and regularity, and hence predictability, to favor predesign
of the whole system. The system’s very design in effect makes a prediction–a
wager, in fact–that the environment will be the way it must be for the system
to work. When the complexity of encountered environments rises, however, and
unpredictability becomes a more severe problem, a different design principle
kicks in: the commando team principle illustrated by such films as “The Guns of
Navarone”: give each agent as much knowledge about the total project as
possible, so that the team has a chance of ad libbing appropriately when
unanticipated obstacles arise.
Fortunately, we don’t have to inspect brain processes directly to get evidence
of the degree to which one design principle or the other is operating in a
particular organism–although in due course it will be wonderful to get
confirmation from neuroscience. In the meantime, we can conduct experiments that
reveal the hidden dissimilarities by showing how bird and child respond to
abnormal obstacles and opportunities along the way.
My favorite example of such an experiment with beavers is Wilsson (1974): It
turns out that beavers hate the sound of running water and will cast about
frantically for something–anything–that will bring relief; Wilsson played
recordings of running water from loudspeakers, and the beavers responded by
plastering the loudspeakers with mud.
So there is a watershed in the terrain of evolutionary design space; when a
control problem lies athwart it, it could be a matter of chance which direction
evolution propelled the successful descendants. Perhaps, then, there are two
ways of tending fires–roughly, the beaver-dam way, and our way. If so, it is a
good thing for us that our ancestors didn’t hit upon the beaver-dam way, for if
they had, the woods might today be full of apes sitting around campfires, but we
would not be here to marvel at them.


4. The Tower of Generate-and-Test
I want to propose a framework in which we can place the various design options
for brains, to see where their power comes from. It is an outrageously
oversimplified structure, but idealization is the price one should often be
willing to pay for synoptic insight. I will call it the Tower of
Generate-and-Test. Endnote 2
In the beginning there was Darwinian evolution of species by natural selection.
A variety of candidate organisms were blindly generated by more or less
arbitrary processes of recombination and mutation of genes. These organisms were
field tested, and only the best designs survived. This is the ground floor of
the tower. Let us call its inhabitants Darwinian creatures. (Is there perhaps a
basement? Recently speculations by physicists and cosmologists about the
evolution of universes opens the door to such a prospect, but I will not explore
it on this occasion. My topic today is the highest stories of the Tower.)
This process went through many millions of cycles, producing many wonderful
designs, both plant and animal, and eventually among its novel creations were
some designs with the property of phenotypic plasticity. The individual
candidate organisms were not wholly designed at birth, or in other words there
were elements of their design that could be adjusted by events that occurred
during the field tests. Some of these candidates, we may suppose, were no better
off than their hard-wired cousins, since they had no way of favoring (selecting
for an encore) the behavioral options they were equipped to “try out”, but
others, we may suppose, were fortunate enough to have wired-in “reinforcers”
that happened to favor Smart Moves, actions that were better for their agents.
These individuals thus confronted the environment by generating a variety of
actions, which they tried out, one by one, until they found one that “worked”.
We may call this subset of Darwinian creatures, the creatures with conditionable
plasticity, Skinnerian creatures, since, as B. F. Skinner was fond of pointing
out, operant conditioning is not just analogous to Darwinian natural selection;
it is continuous with it. “Where inherited behavior leaves off, the inherited
modifiability of the process of conditioning takes over.” (Skinner, 1953, p.83)
Skinnerian conditioning is a fine capacity to have, so long as you are not
killed by one of your early errors. A better system involves preselection among
all the possible behaviors or actions, weeding out the truly stupid options
before risking them in the harsh world. We human beings are creatures capable of
this third refinement, but we are probably not alone. We may call the
beneficiaries of this third story in the Tower Popperian creatures, since as Sir
Karl Popper once elegantly put it, this design enhancement “permits our
hypotheses to die in our stead.” Unlike the merely Skinnerian creatures who
survive because they are lucky, we Popperian creatures survive because we’re
smart–of course we’re just lucky to be smart, but that’s better than just being
lucky. Endnote 3
But how is this preselection in Popperian agents to be done? Where is the
feedback to come from? It must come from a sort of inner environment–an inner
something-or-other that is structured in such a way that the surrogate actions
it favors are more often than not the very actions the real world would also
bless, if they were actually performed. In short, the inner environment,
whatever it is, must contain lots of information about the outer environment and
its regularities. Nothing else (except magic) could provide preselection worth
having. Now here we must be very careful not to think of this inner environment
as simply a replica of the outer world, with all its physical contingencies
reproduced. (In such a miraculous toy world, the little hot stove in your head
would be hot enough to actually burn the little finger in your head that you
placed on it!) The information about the world has to be there, but it also has
to be structured in such a way that there is a non-miraculous explanation of how
it got there, how it is maintained, and how it actually achieves the
preselective effects that are its raison d’etre.


We have now reached the story of the Tower on which I want to build. Once we get
to Popperian creatures, creatures whose brains have the potential to be shaped
into inner environments with preselective prowess, what happens next? How does
new information about the outer environment get incorporated into these brains?
This is where earlier design decisions–and in particular, choices between Need
to Know and Commando Team–come back to haunt the designer; for if a particular
species’ brain design has already gone down the Need to Know path with regard to
some control problem, only minor modifications (fine tuning, you might say) can
be readily made to the existing structures, so the only hope of making a major
revision of the internal environment to account for new problems, new features
of the external environment that matter, is to submerge the old hard-wiring
under a new layer of pre-emptive control (a theme developed in the work of the
AI researcher Rodney Brooks). It is these higher levels of control that have the
potential for vast increases in versatility. And it is at these levels in
particular, that we should look for the role of language (when it finally
arrives on the scene), in turning our brains into virtuoso pre-selectors.
We engage in our share of rather mindless routine behavior, but our important
acts are often directed on the world with incredible cunning, composing projects
exquisitely designed under the influence of vast libraries of information about
the world. The instinctual actions we share with other species show the benefits
derived by the harrowing explorations of our ancestors. The imitative actions we
share with some higher animals may show the benefits of information gathered not
just by our ancestors, but also by our social groups over generations,
transmitted non-genetically by a “tradition” of imitation. But our more
deliberatively planned acts show the benefits of information gathered and
transmitted by our conspecifics in every culture, including, moreover, items of
information that no single individual has embodied or understood in any sense.
And while some of this information may be of rather ancient acquisition, much of
it is brand new. When comparing the time scales of genetic and cultural
evolution, it is useful to bear in mind that we here today–every one of us–can
easily understand many ideas that were simply unthinkable by the geniuses in our
grandparents’ generation!
The successors to mere Popperian creatures are those whose inner environments
are informed by the designed portions of the outer environment. We may call this
sub-sub-subset of Darwinian creatures Gregorian creatures, since Richard
Gregory, the first speaker in this series, is to my mind the pre-eminent
theorist of the role of information–or more exactly, what Gregory calls
Potential Intelligence–in the creation of Smart Moves–or what Gregory calls
Kinetic Intelligence. Gregory observes that a pair of scissors, as a
well-designed artifact, is not just a result of intelligence, but an endower of
intelligence (external potential intelligence), in a very straightforward and
intuitive sense: when you give someone a pair of scissors, you enhance their
potential to arrive more safely and swiftly at Smart Moves (Gregory 1981,
pp.311ff).


Anthropologists have long recognized that the advent of tool use accompanied a
major increase in intelligence. Our fascination with the discovery that
chimpanzees in the wild fish for termites with crudely prepared fishing sticks
is not misplaced. This fact takes on further significance when we learn that not
all chimpanzees have hit upon this trick; in some chimpanzee “cultures” termites
are a present but unexploited food source. This reminds us that tool use is a
two-way sign of intelligence; not only does it require intelligence to recognize
and maintain a tool (let alone fabricate one), but it confers intelligence on
those who are lucky enough to be given the tool. The better designed the tool,
the more information is embedded in its fabrication, the more potential
intelligence it confers on its user. And among the pre-eminent tools, Gregory
reminds us, are what he calls mind-tools: words. What happens to a human or
hominid brain when it becomes equipped with words? I have arrived, finally, back
at the question with which I began.
5. What words do to us
There are two related mistakes that are perennially tempting to theorists
thinking about the evolution of language and thinking. The first is to suppose
that the manifest benefits of communication to humanity (the group, or the
species) might themselves explain the evolution of language. The default
supposition of evolutionary theory must be that individuals are initially
competitive, not cooperative, and while this default can be most interestingly
overridden by special conditions, the burden is always to demonstrate the
existence of the special conditions. The second mistake is to suppose that
mind-tools–words, ideas, techniques–that were not “good for us” would not
survive the competition. The best general antidote I know to both these errors
is Richard Dawkins’ discussion of memes in The Selfish Gene Endnote 4. The best
detailed discussion I know of the problem of designing communication under the
constraint of competitive communicators is by the last speaker in this series,
Dan Sperber, and his co-author Deirdre Wilson, in their excellent book,
Relevance: a Theory of Communication (Cambridge, MA: Harvard Univ. Press, 1986.)
One upshot of the considerations raised by these thinkers is that one may
usefully think of words–the most effective vehicles for memes–as invading or
parasitizing a brain, not simply being acquired by a brain. Endnote 5 What is
the shape of this environment when words first enter it? It is definitely not an
even playing field or a tabula rasa. Our newfound words must anchor themselves
on the hills and valleys of a landscape of considerable complexity. Thanks to
earlier evolutionary pressures, our innate quality spaces are species-specific,
narcissistic, and even idiosyncratic from individual to individual.
A number of investigators are currently exploring portions of this terrain. The
psychologist Frank Keil and his colleagues at Cornell have evidence that certain
highly abstract concepts–such as the concepts of being alive or ownership, for
instance–have a genetically imposed head start in the young child’s kit of
mind-tools; when the specific words for owning, giving and taking, keeping and
hiding, and their kin enter a child’s brain, they find homes already partially
built for them. Ray Jackendoff and other linguists have identified fundamental
structures of spatial representation–notably designed to enhance the control of
locomotion and the placement of movable things–that underlie our intuitions
about concepts like beside, on, behind, and their kin. Nicholas Humphrey has
argued in recent years that there must be a genetic predisposition for adopting
what I have called the intentional stance, and Alan Leslie and others have
developed evidence for this, in the form of what he calls a “theory of mind
module” designed to generate second-order beliefs (beliefs about the beliefs and
other mental states of others). Some autistic children seem to be well-described
as suffering from the disabling of this module, for which they can occasionally
make interesting compensatory adjustments. (See Further Reading.)
We are only just beginning to discern the details of the interactions between
such pre-existing information structures and the arrival of language, so
theorists who have opportunistically ignored the phenomenon up till now have
nothing to apologize for. The time has come, however, to change tactics. In
Artificial Intelligence, for instance, even the most ambitiously realistic
systems–such as Soar, the star of Allen Newell’s Unified Theories of Cognition
(1990)–are described without so much as a hint about which features, if any,
are dependent on the system’s having acquired a natural language with which to
supplement its native representational facilities. Endnote 6 The result is that
most AI agents, the robotic as well as the bed-ridden, are designed on the model
of the walking encyclopedia, as if all the information in the inner environment
were in the form of facts told at one time or another to the system. Endnote 7
And in the philosophy of mind, there is a similar tradition of
theory-construction and debate about the nature of belief, desire and
intention–philosophical “theories of mental representation”–fed on a diet
exclusively drawn from language-infected cognitive states. Endnote 8 Tom
believes that snow is white. Do polar bears believe that snow is white? In the
same sense? Supposing one might develop a good general theory of belief by
looking exclusively at such specialized examples is like supposing one might
develop a good general theory of motor control by looking exclusively at
examples of people driving automobiles in city traffic. “Hey, if that isn’t
motor control, what is?”–a silly pun echoed, I am claiming, by the philosopher
who says “Tom believes snow is white–hey, if that isn’t a belief, what is?”
6. What words do for us
John Holland, a pioneer researcher on genetic algorithms, has recently
summarized the powers of the Popperian internal environment, adding a nice
wrinkle.
An internal model allows a system to look ahead to the future consequences of
current actions, without actually committing itself to those actions. In
particular, the system can avoid acts that would set it irretrievably down
some road to future disaster (“stepping off a cliff”). Less dramatically, but
equally important, the model enables the agent to make current “stage-setting”
moves that set up later moves that are obviously advantageous. The very
essence of a competitive advantage, whether it be in chess or economics, is
the discovery and execution of stage-setting moves.
–John Holland, “Complex Adaptive Systems,” Daedalus, Winter, 1992, p25.
But how intricate and long-range can the “stage-setting” look-ahead be without
the intervention of language to help control the manipulation of the model? This
is the relevance of my question at the outset about the chimp’s capacities to
visualize a novel scene. As Merlin Donald points out in his thought-provoking
book (p.35), Darwin was convinced that language was the prerequisite for “long
trains of thought,” and this claim has been differently argued for several
recent theorists, especially Julian Jaynes and Howard Margolis. Long trains of
thought have to be controlled, or they will wander off into delicious if futile
woolgathering. These authors suggest, plausibly, that the self-exhortations and
reminders made possible by language are actually essential to maintaining the
sorts of long-term projects only we human beings engage in (unless, like the
beaver, we have a built-in specialist for completing a particular long term
project).
Merlin Donald resists this plausible conjecture, and offers a variety of grounds
for believing that the sorts of thinking that we can engage in without language
are remarkably sophisticated. I commend his argument to your attention in spite
of the doubts about it I will now briefly raise. Donald’s argument depends
heavily on two sources of information, both problematic in my opinion. First, he
makes strong claims about the capabilities of those congenitally Deaf human
beings who have not yet developed (so far as anyone can tell) any natural
language–in particular, signing. Second, he draws our attention to the amazing
case of Brother John, a French Canadian monk who suffers from frequent epileptic
seizures that do not render him unconscious or immobile, but just totally
aphasic, for periods of a few minutes or hours. During these paroxysms of
aphasia, we are told, Brother John had no language, either external or internal.
That is, he could neither comprehend nor produce words of his native tongue, not
even “to himself”. Endnote 9 At the same time, Brother John can “still record
the episodes of life, assess events, assign meanings and thematic roles to
agents in various situations, acquire and execute complex skills, learn and
remember how to behave in a variety of settings.” (Donald, p.89.)
My doubts about the use to which Donald wants to put these findings are
straightforward, and should be readily resolvable in time: both Brother John and
the long-term language-less Deaf people, are in different ways and to different
degrees, still the beneficiaries of the shaping role of language. In the case of
Brother John, his performance during aphasic paroxysm relies, as Lecours and
Joanette note, on “language-mediated apprenticeships”.


Brother John maintains, for instance, that he need not tell himself the words
“tape recorder,” “magnetic tape,” “red button on the left,” “turn,” “push” and
so forth . . . in order to be capable of properly operating a tape recorder. .
. . (Roche Lecours and Joanette, p.20)
The Deaf who lack Sign–a group whose numbers are diminishing today, thank
goodness–lack Brother John’s specific language-mediated apprenticeships, but we
simply don’t know–yet–what structures in their brains are indirect products of
the language that most of their ancestors in recent millennia have shared. The
evidence that Donald adduces for the powers of language-less thought is thus
potentially misleading. These varieties of language-less thought, like barefoot
waterskiing, may be possible only for brief periods, and only after a
preparatory period that includes the very feature whose absence is later so
striking.
There are indirect ways of testing the hypotheses implied by these doubts.
Consider episodic memory, for instance. When a dog retrieves a bone it has
buried, it manifests an effect on its memory, but must the dog, in retrieving
the bone, actually recollect the episode of burying? (Perhaps you can name the
current U. S. Secretary of State, but can you recall the occasion of learning
his name?) The capacity for genuine episodic recollecting–as opposed to
semantic memory installed by a single episode of learning–is in need of careful
analysis and investigation. Donald follows Jane Goodall in claiming that
chimpanzees in the wild are “able to perceive social events accurately and to
remember them” (p.157)–as episodes in memory. But we have not really been given
any evidence from which this strong thesis follows; the social perspicuity of
the chimpanzees might be largely due to specialized perceptual talents
interacting with specialized signs–suppose, for instance, that there is
something subtle about the posture of a subordinate facing a superior that
instantly–visually–tells an observer chimp (but not an human observer) which
is subordinate, and how much. Experiments that would demonstrate a genuine
capacity for episodic memory in chimpanzees would have to involve circumstances
in which a episode was observed or experienced, but in which its relevance as a
premise for some social inference was not yet determined–so no “inference”
could be drawn at once. If something that transpired later suddenly gave a
retrospective relevance to the earlier episode, and if a chimpanzee can tumble
to that fact, this would be evidence–but not yet conclusive evidence–of
episodic memory.
Another way of testing for episodic memory in the absence of language would be
to let a chimpanzee observe–once–a relatively novel and elaborate behavioral
sequence that accomplishes some end (e.g., to make the door open, you stamp
three times, turn in a circle and then push both buttons at once), and see if
the chimpanzee, faced with the need to accomplish the same end, can even come
close to reproducing the sequence. It is not that there is any doubt that
chimpanzee brain tissue is capable of storing this much information–it can
obviously store vastly more than is required for such a simple feat–but whether
the chimpanzee can exploit this storage medium in such an adaptive way on short
notice. And that is the sort of question that no amount of microscopic
brain-study is going to shed much light on.


7. The art of making mistakes: the next story
This brings me to my final step up the Tower of Generate-and-Test. There is one
more embodiment of this wonderful idea, and it is the one that gives our minds
their greatest power: once we have language–a bountiful kit of mind-tools–we
can use them in the structure of deliberate, foresightful generate-and-test
known as science. All the other varieties of generate-and-test are willy-nilly.


The soliloquy that accompanies the errors committed by the lowliest Skinnerian
creature might be “Well, I mustn’t do that again!” and the hardest lesson for
any agent to learn, apparently, is how to learn from one’s own mistakes. In
order to learn from them, one has to be able to contemplate them, and this is no
small matter. Life rushes on, and unless one has developed positive strategies
for recording one’s tracks, the task known in AI as credit assignment (also,
known, of course, as blame assignment!) is insoluble. The advent of high-speed
still photography was a revolutionary technological advance for science because
it permitted human beings, for the first time, to examine complicated temporal
phenomena not in real time, but in their own good time–in leisurely, methodical
backtracking analysis of the traces they had created of those complicated
events. Here a technological advance carried in its wake a huge enhancement in
cognitive power. The advent of language was an exactly parallel boon for human
beings, a technology that created a whole new class of objects-to-contemplate,
verbally embodied surrogates that could be reviewed in any order at any pace.
And this opened up a new dimension of self-improvement–all one had to do was to
learn to savor one’s own mistakes.


But science is not just a matter of making mistakes, but of making mistakes in
public. Making mistakes for all to see, in the hopes of getting the others to
help with the corrections. It has been plausibly maintained, by Nicholas
Humphrey, David Premack and others, that chimpanzees are natural
psychologists–what I would call second-order intentional systems–but if they
are, they nevertheless lack a crucial feature shared by all human natural
psychologists, folk and professional varieties: they never get to compare notes.
They never dispute over attributions, and ask for the grounds for each others’
conclusions. No wonder their comprehension is so limited. Ours would be, too, if
we had to generate it all on our own.
**
Let me sum up the results of my rather swift and superficial survey. Our human
brains, and only human brains, have been armed by habits and methods, mind-tools
and information, drawn from millions of other brains to which we are not
genetically related. This, amplified by the deliberate use of generate-and-test
in science, puts our minds on a different plane from the minds of our nearest
relatives among the animals. This species-specific process of enhancement has
become so swift and powerful that a single generation of its design improvements
can now dwarf the R-and-D efforts of millions of years of evolution by natural
selection. So while we cannot rule out the possibility in principle that our
minds will be cognitively closed to some domain or other, no good “naturalistic”
reason to believe this can be discovered in our animal origins. On the contrary,
a proper application of Darwinian thinking suggests that if we survive our
current self-induced environmental crises, our capacity to comprehend will
continue to grow by increments that are now incomprehensible to us.


Further Reading
Rodney Brooks, 1991, “Intelligence Without Representation,” Artificial
Intelligence Journal, 47, pp.139-59.


William Calvin, 1990, The Ascent of Mind: Ice Age Climates and the Evolution of
Intelligence, New York: Bantam
Richard Dawkins, 1976, The Selfish Gene, Oxford: Oxford Univ. Press.


Daniel Dennett, “The brain and its boundaries, ” review of McGinn, 1990, in TLS,
May 10, 1991 (corrected by erratum notice on May 24, p29).
Jared Diamond, 1992, The Third Chimpanzee: The Evolution and Future of the Human
Animal, New York: Harper
Merlin Donald, 1991, Origins of the Modern Mind: Three Stages in the Evolution
of Culture and Cognition, Cambridge, MA: Harvard Univ. Press
Richard Gregory 1981, Mind in Science, Cambridge Univ. Press.


Ray Jackendoff, 1987, Consciousness and the Computational Mind, Cambridge, MA:
MIT Press/A Bradford Book.


Julian Jaynes, 1976, The Origins of Consciousness in the Breakdown of the
Bicameral Mind, Boston: Houghton Mifflin
Frank Keil, forthcoming, “The Origins of an Autonomous Biology,” in Minnesota
Symposium, details forthcoming
Alan Leslie, 1992, “Pretense, Autism and the Theory-of-Mind Module,” Current
Directions in Psychological Science, 1, pp.18-21.


Colin McGinn, 1990, The Problem of Consciousness, Oxford: Blackwell.


Allen Newell, 1990, Unifed Theories of Cognition, Harvard Univ. Press.


Howard Margolis, 1987, Patterns, Thinking and Cognition, Univ. of Chicago Press.


Andre Roche Lecours and Yves Joanette, “Linguistic and Other Psychological
Aspects of Praoxysmal Aphasia,” Brain and Language, 10, pp.1-23, 1980.


John Holland, “Complex Adaptive Systems,” Daedalus, Winter, 1992, p25.


Nicholas Humphrey, 1986, The Inner Eye, London: Faber & Faber.


David Premack, 1986, Gavagai! Or the Future History of the Animal Language
Controversy, Cambridge, MA: MIT Press.


B. F. Skinner, 1953, Science and Human Behavior, New Yorkl: MacMillan.


Dan Sperber and Deirdre Wilson, 1986, Relevance: a Theory of Communication,
Cambridge, MA: Harvard Univ. Press.
L. Wilsson, 1974, “Observations and Experiments on the Ethology of the European
Beaver,” Viltrevy, Swedish Wildlife, 8, pp.115-266.


Endnotes
1. See the discussion of Steven Kosslyn’s concept of “visual generativity” and
its relation to language, in Donald, 1991, pp.72-5.
2.This is an elaboration of ideas to be found in my “Why the Law of Effect Will
Not Go Away,” 1974, Journal of the Theory of Social Behaviour, 5, pp.169-87,
reprinted in Brainstorms, 1978.


3. For more on the relationship between luck and talent (and free will and
responsibility), see my Elbow Room: The Varieties of Free Will Worth Wanting,
1984.


4.R. Dawkins, 1976, The Selfish Gene, Oxford Univ. Press. See also my
discussions of the concept in “Memes and the Exploitation of the Imagination,”
Journal of Aesthetics and Art Criticism, 1990, 48, pp. 127-35. and in my book,
Consciousness Explained, 1991.


5.This idea is defended in chapters 7 and 8 of Consciousness Explained.
6.See my review of Newell, forthcoming in Artificial Intelligence, special issue
devoted to Newell’s book.


7. Cf. Dennett, 1991, “Mother Nature versus the Walking Encyclopedia,” in W.
Ramsey, S. Stich, and D. Rumelhart, eds., Philosophy and Connectionist Theory,
Hillsdale, NJ: Erlbaum.


8. Such belief-like states are what I have called “opinions” (in Brainstorms,
ch. 16.)
9.In Consciousness Explained, I deliberately made up–as an implausible but
possible fiction–a case of temporary total aphasia: “there is an herb an
overdose of which makes you incapable of understanding spoken sentences in your
native language . . ,” adding that for all I knew, it might be fact, not fiction
(p.69). If Brother John’s epilepsy could be brought on by an overdose of an
herb, the case would be complete–if Brother John’s case is the fact it seems to
be. A review of the original report (Roche Lecours and Joanette, 1980) leaves
unanswered questions, but no grounds for dismissal that I could detect.

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