A Radically Different Kind of Faculty

Riding a pony in the mountainous country of Lesotho, I became nervous when the narrow, rock-strewn trail we were negotiating skirted the edges of steep precipices. I found myself paying close attention, at such places, to where my horse was placing its hooves. On several occasions, I saw it test footholds, before shifting its full weight onto them. These were reassuring acts. My animal had the “horse sense,” I realized, to choose “wise” or “judicious” ways to negotiate that potentially hazardous trail, without possessing anything like a human level of intelligence. Nature had, it seemed, equipped it with neural machinery dedicated to the production of sophisticated all-terrain mobility. That machinery may have been cheap and simple compared to the more general and abstract kind of intelligence our species possesses, but I began to realise to my relief that it seemed to be reliable.

Natural selection is every bit as capable of assembling complex behaviours and abilities as it is of producing complex body shapes.

Consider, for example, the inborn promptings and guidance which will allow a young Arctic tern to make its first migratory flight from northern Canada down to Antarctica. The bird’s parents will leave before it does, so it has to rely entirely on a genetic “navigation package” to initiate and complete that ten-thousand mile journey. Ingenious experiments relating to the directions in which caged birds orient themselves in planetariums have shown that some migratory bird species have “star maps” written into their DNA, and it’s not unlikely that Arctic terns are also equipped with “instinctive” sky charts of that kind. It’s difficult to imagine how chance variations – each separately advantageous to its possessor – could have accumulated to put together that kind of map, as well as the “clocks,” “magnetic compasses” and other specialized structures which may constitute the tern’s “avionics.” Natural selection is, however, as Richard Dawkins’ 1997 Climbing Mount Improbable demonstrates so convincingly, equal to tasks of that kind.

While the mills of natural selection can, therefore, grind exceedingly fine, they also grind very slowly.

Bats took millions of years to develop the ability to send out the sound-pulses whose echoes locate the insects they feed on, while the insect species which execute spiralling crash-dives when they hear those sound-pulses, took similarly big chunks of time to evolve that defense. If insects were able to understand what was happening when they heard bats’ “sonar” pulses, then they could have adopted countermeasures such as the crash-dive immediately. Because they don’t have that kind of understanding, the impulse to make power-dives in response to sonar pulses had, of course, to be constructed entirely by the accumulation, over thousand of generations, of chance variations in the reactions of individuals of their species to such sonar pulses.

Animals of all kinds are equipped to react to particular situations in such uncomprehending but appropriate ways.

Humans themselves don’t have to understand that spiders can give them dangerous bites, or that contact with excrement can pass contagious diseases to them. Specialized neural structures tell us instead – in a peremptory way that bypasses logic – that spiders look frightening and that excrement is disgusting.

Much of what we think and do is powerfully affected by instincts. We don’t have to be taught to fear heights, enjoy sweet tastes, seek the respect of our fellow-humans, or find someone beautiful.

A multitude of instincts shape our behavior with such effortless power that we tend to be blind to their existence.

“Why,” William James asked, “ does a particular maiden turn our wits so upside-down?”

The common man can only say, “Of course we … love the maiden, that beautiful soul clad in that perfect form, so palpably and flagrantly made from all eternity to be loved!”

It takes what James calls “a mind debauched by learning” to understand that our fascination with the maiden (or her male counterpart) is a product of purpose-built brain regions whose operations are triggered by criteria installed in our minds by natural selection for reproductive purposes — criteria that would be as meaningless to other species as theirs would be to us.

“What voluptuous thrill,” James goes on to ask,

may not shake a fly, when she at last discovers the one particular leaf, or carrion, or bit of dung, that out of all the world can stimulate her ovipositor to its discharge? Does not the discharge then seem to her the only fitting thing? And need she care or know anything about the future maggot and its food?

Strokes and other cerebral disruptions can bring home to us in a dramatic way that ostensibly “easy” or “natural” activities like walking and eating are, like sexual attraction, the elaborate productions of specialized neurological systems. Even the moral dimension of our species’ existence, often thought of as a kind of opposite pole to the instinct-dominated, “animal” part of our make-up, may have originated in, and still be under the influence of, the kind of “special-purpose” neural structures which characterize instinctive behavior.

“I fully subscribe,” Darwin wrote,

to the judgement of those writers who maintain that of all the differences between man and the lower animals, the moral sense or conscience is by far the most important. This sense… is summed up in that short but imperious word ought, so full of high significance. It is the most noble of all the attributes of man, leading him without a moment’s hesitation to risk his life for that of a fellow-creature; or after due deliberation, impelled simply by the deep feeling of right or duty, to sacrifice it in some great cause.

Darwin goes on, however, to point out that, despite the fact that morality appears to set us apart from the “lower animals,” its origins also lie in natural selection:

The first foundation or origin of the moral sense lies in the social sense… Animals endowed with the social instincts take pleasure in each other’s company, warn each other of danger, defend and aid each other in many ways. These instincts are not extended to all the individuals of the species, but only to those of the same community. As they are highly beneficial to the species, they have in all probability been acquired through natural selection.

From this Darwin concluded that

…any animal whatever, endowed with well-marked social instincts, the parental and filial affections being here included, would inevitably acquire a moral sense or conscience, as soon as its intellectual powers had become as well, or nearly as well developed, as in man.

This argument takes the theory of natural selection into what some see as the inner sanctum of humanness. Even today, a century and and a half after Darwin formulated it, it can still present an unsettling challenge to both religious and humanist ideas of morality. “Your father’s opinion that all morality has grown up by evolution,” Emma Darwin wrote to her son Francis after her husband’s death, “is painful to me.”

* * *

No part of the human reality appears, then, to be too complex — or indeed to “exalted” — to be the product of evolution by natural selection. Evolution can, as we’ve seen, construct instinctive behaviors whose sophistication strains our credulity. “There is simply no denying,” Daniel Dennett declares in his Darwin’s Dangerous Idea, “the breathtaking brilliance of the designs to be found in Nature”:

Time and time again, biologists baffled by some apparently futile or maladroit bit of bad design in nature, have come to see that they have underestimated the ingenuity, the sheer brilliance, the depth of insight to be discovered in one of Mother Nature’s creations. Francis Crick has mischievously baptized this trend in the name of his colleague Leslie Orgel, speaking of what he calls ‘Orgel’s Second Rule: Evolution is cleverer than you are.’

“Orgel’s Second Rule” is — at least at this stage of our intellectual development — unassailable. The level of “ingenuity” which has gone into the assembly of the instinctive behaviors we’ve been talking about, still exceeds that of our species by a wide margin.

And yet the world of instinctive behavior has limitations. They can only evolve in response to situations that arise over and over in the life of a species, for thousands of generations. Natural selection isn’t flexible enough to respond appropriately to the enormous world of opportunities which don’t present themselves in this repetitive, “stereotyped” way. If an organism could, therefore, retain the enormous benefits which instinctual behaviors confer on it, but develop, in addition, a method of devising useful responses to opportunities lying beyond the reach of the instinct-building mechanism, it would gain access to a cornucopia of new strategies to maximise its survival and reproduction.

The human family has developed such a method. It did so by evolving “general-purpose” computational machinery that can “think up” or invent useful responses to this previously unexploitable class of opportunities. That computational machinery hasn’t just enabled us to respond to a much broader range of opportunities – it has also enabled us to respond to such opportunities in far less time than natural selection takes to assemble its “responses.”

It took evolution tens of millions of years to develop the knife-edged “carnassial” or meat-cutting teeth with which lions and other cats are equipped, but the development by humans of the ability to cut meat and other substances with stone tools appeared (by way of invention, or more accurately, a series of inventions) over a much shorter period of time.

Because an individual is “ὄντος” (“ontos”) in Greek, and because innovations resulting from inventions and improvisations are made by individuals (acting either alone or in concert), new behaviors like the manufacture of stone tools are spoken of as “ontogenetic” innovations.

The meat-cutting teeth of a lion are, in contrast to this, a “phylogenetic” innovation, because they were produced by the φῦλον (“phylum”) of the lion by way of evolution. Because they are produced by evolution rather than invention, phylogenetic innovations typically take a great many individual lifetimes to make their appearance.

Ontogenetic innovations can, on the other hand, literally appear overnight. This has given hominins — the human family — an overwhelming advantage over all other members of the biosphere.

The psychologist Leda Cosmides and the anthropologist John Tooby (seen above) describe this advantage, and some of its effects, as follows:

Instead of being constrained to innovate only in phylogenetic time, …[humans]… engage in ontogenetic ambushes against their antagonists – innovations that are too rapid with respect to evolutionary time for their antagonists to evolve defenses by natural selection. Armed with this advantage, hominids have exploded into new habitats, developed an astonishing diversity of subsistence and resource extraction methods, caused the extinction of many prey species in whatever environments they have penetrated, and generated an array of social systems far more extensive than that found in any other single species.

* * *

I don’t want to suggest that the world of “ontogenetic” solutions is entirely closed to non-hominin organisms. Some species have been able to respond to novel opportunities in ways that can fairly be called “inventive”: robins and tits have learned, for instance, to peck open the aluminum caps on milk bottles in Britain (and to pass their “discovery” on to other individuals of their two species by example).

Other non-human animals use general-purpose computational machinery analogous to that evolved by our species, to “think up” responses to novel opportunities.

Ravens kept by Bernd Heinrich in Maine, were able, for instance, to get hold of meat suspended from a perch by two-foot pieces of string, by flying to the perch, reaching down to pull a length of the string up with their beaks, standing on it with a foot, and then repeating the operation. This solution was not, Heinrich thinks, discovered by trial and error. For several hours after he tied the meat-and-string device to the perch, none of the birds came near it. Then one of them abruptly flew to the perch, and used the “beak over foot” method to haul the meat up without further ado. He concludes that the solution “occurred to” that bird as the result of a mental examination of the problem.

Corvids, the group to which ravens, crows, magpies and blue jays belong, are a very smart family. In Richmond, British Columbia, I witnessed crows dropping hazel nuts which they had brought from a nearby tree onto a busy street during rush-hour, so that the cars’ tires would break their shells. It was a startling sight to see those birds swooping down into the traffic to retrieve the kernels of those nuts — and to steal them from one another.

A Japanese macaque monkey became famous for learning to separate the cooked rice given to her by humans from sand by floating the former away from the latter in water, a method which some, but not all, members of her band were able to imitate.

The world of invention and improvisation does not, moreover, seem to be restricted to particularly clever groups like primates and corvids: most if not all vertebrates may, in a rudimentary and limited way, be able to “think up” beneficial responses to novel opportunities.

An intelligent invertebrate (and no, the phrase “intelligent invertebrate” isn’t an oxymoron!) like the octopus Amphioctopus marginatus can carry around with it the shells of fellow-members of the phylum Mollusca, or a pair of coconut half-shells cut by humans which it will fit together around it, to conceal itself from predators and/or lie in wait for prey such as crabs.

To say without qualification, however, that “both humans and some non-human organisms can invent beneficial new ways of doing things” would be as misleading as saying without qualification that “both humans and earthworms have light-perceiving organs.”

Earthworms don’t have eyes, and they can only detect changes in the intensity of light falling on the front ends of their bodies with the aid of light-sensitive cells situated in that region. Humans, on the other hand, can use light to create exquisitely precise mental images of their surroundings.

The difference between the light-manipulating powers of humans and those of earthworms is, as I see it, a roughly accurate metaphor for the difference between the inventive power of humans and that of non-humans. The power of the former is so much greater than the latter that it is, for all practical purposes, a radically different kind of faculty.

* * *

The ability to “think up” solutions to novel problems seems to require the ability to construct mental models of causal relationships in the real world. “What if,” a member of our species might ask herself, “I take the noose I’ve tied into this cord, and hang it across an overgrown path that small antelopes like duikers use, and then tie the other end of the cord to a branch?” To answer that question, her brain will produce a kind of “movie” of the consequences likely to flow from this action. The plot-line of that “movie” will conform to her idea of how the causal structure of the real world works. If her understanding of that causal structure is accurate enough, it will allow her to predict correctly that duikers aren’t likely to spot a noose positioned across a narrow path through tall grass, and that they could, therefore, put their heads into such nooses and then pull them tight in their efforts to escape.

If too many duikers manage to pull their heads out of those nooses, (in either her mental movie or in reality) then sequels will appear, produced, perhaps, by the original snare-designer, or by others, in which young trees whose crowns are bent down and secured to the ground with hair-trigger connections, might spring upright to hoist the hapless little antelopes off their feet when those connections are disengaged by a tug on the noose.

Hominins have become so proficient at using such “movies” or “models” to evaluate possibly advantageous new behaviors, that they’ve become, for all practical purposes, the sole occupants of what John Tooby, Irven de Vore and Leda Cosmides speak of as “the cognitive niche.”

* * *

One might suppose that our duiker-trapper was able to “think up” her snares because she had emancipated herself from the “primitive” instinctual functions of her brain, but that doesn’t appear to be the case. The “general-purpose” computational machinery which our species has evolved hasn’t turned its back on our special-purpose neural structures – our instincts – as if they were poor relatives. It employs them, instead, and seems, in fact, to be dependent on them. Our duiker-trapper’s general-purpose computational machinery might have been overwhelmed, for instance, by the volume and complexity of the calculations required to model the physics of the snares she was considering, if it didn’t have a “cheat sheet” of “internal” or “intuitive” physics to refer to.

General-purpose or inventive intelligence is also thought to employ special-purpose instinctual modules to help avoid what cognitive theorists and specialists in the field of artificial intelligence refer to as “combinatorial explosions”: the fact that even a small increase in the elements of a problem leads to exponential – i.e. explosive – growth in the number of ways those elements can combine with each other. The nine-step game of tic-tac-toe can, for instance, unfold in 362,880 different ways. Computers can review all these in real time in order to avoid the ones that lead to loss, but humans can’t ordinarily manage a calculation of that size.

The world of all possible chess games is much too big to be subjected to a review of this kind by either humans or computers. (Computers beat us at chess only because they can see further into that unthinkably immense realm, i.e. construct bigger “trees” of consequences for particular moves than we can.)

The process of human inventiveness cannot and does not, in any event, involve sorting through enormous numbers of combinations by brute force. Trying to design a duiker-snare by considering all the possible ways that the raw materials in your environment can be processed and combined, would be like trying to write a book on French cooking by generating all the permutations which the characters printable by your computer, including blank spaces, can assume in a 200-page sequence. Although those permutations include what Daniel Dennett refers to in his Darwin’s Dangerous Idea as a “Vast” number of books on French cooking, an attempt to generate even one of them by a process of random iteration, would be Vastly unlikely to succeed on a schedule relevant to you, your publisher, or, indeed, the lifetime of the Universe.

Our duiker-snare designer could not, therefore, have succeeded in her task if her thinking wasn’t “shepherded” toward potentially productive areas with the help of well-stocked caches of instinctual, personal and cultural information, as well as input from her biological drives and emotions.

Cognitive theorists talk about this “shepherding” process with words related to steering (cybernetic) or finding (heuristic), but it remains an intriguingly mysterious process. “Nothing is more admirable,” the Scottish philosopher David Hume wrote almost three centuries ago in his Treatise of Human Nature,

than the readiness with which the imagination suggests its ideas and presents them at the very instant in which they become necessary or useful. The fancy runs from one end of the universe to the other in collecting those ideas which belong to any subject. One would think the whole intellectual world of ideas was at once subjected to our view and we did nothing but pick out such as were most proper for our purpose. There may not, however, be any present, besides those very ideas that are thus collected by a kind of magical faculty of the soul…

That “magical faculty” is still, to use Hume’s own words, “inexplicable by the utmost efforts of human understanding.” Its results are, however, familiar enough: while human thought-processes are fallible, they can make breathtaking leaps of discovery and invention. Some of those leaps are made in at least partly conscious ways, while others may occur without the intervention of conscious logic, as “revelations,” intuitions, dreams and gut feelings.

* * *

The “general-purpose” or “abstract” intelligence we’ve been talking about is obviously an immensely beneficial tool. It may seem surprising, therefore, that, in over four billion years of biological evolution only one family – that of the hominins – has managed to develop it.

Presumably abstract intelligence took more time to evolve than the modules which run specific or “instinctual” mental abilities (like my Lesotho pony’s ability to negotiate precipitous mountain trails) because the complexity of the neural systems which run the former is presumably of a considerably higher order than those which manage the latter. It’s conceivable, too, that an abstract intelligence of our kind could not have come into existence before the “operating system” of instinctual behaviors and information on which it appears to depend, reached a critical level of richness and flexibility.

Speculating along similar lines more than a century ago, William James suggested that the power of the human intellect stems from the fact that our species has more, rather than less, instincts than other animals do.

It may be a truism to say this, but our ability to engage in general-purpose computation must have began to appear, like any other biological system, as soon as it became both beneficial and feasible for natural selection to assemble it. Having made that appearance, it has, however, given our species the power to transform the biosphere so profoundly, to monopolise the cognitive niche so completely,  that no other organism on this planet may get the opportunity of evolving it again.

* * *

Propelled by the immense and unprecedented power of ontogenetic innovation, our species has “exploded” (as Tooby and Cosmides put it) into new environments across the planet.  In almost every one of those new habitats, we caused, also in those authors’ words, “the extinction of many species.” Counterintuitively perhaps, the largest animals living in those newly-settled regions — the megafauna — proved to be the most vulnerable to human-caused extinction.

Some of us are still denying that humans caused the extinction of the megafauna that inhabited Australia and the Americas when our species first moved onto those land masses, because we can’t accept the disconcerting truth that our species’ unprecedented inventive powers had, by that time, already begun to overwhelm the ecological dynamic that had managed — successfully, before the rise of human inventiveness — to limit the numbers and impact of each species to a level consistent with the maintenance of biodiversity.

And it’s important to note, in this context, that it was the survival instinct, rather then greed, that impelled us to overwhelm that dynamic: nature doesn’t ask any organism to exercise restraint or “go easy” in its efforts to improve its survival prospects. It requires them, on the contrary, to “rage, rage” against the limitations imposed on them by the ecology — to use every available stratagem to prevail over the predation, hunger, or interspecies conflict which might at a given moment be threatening their survival. The members of any animal species that happened to acquire our level of intelligence would clearly use it, therefore, as we’ve been using it, to boost the survival chances of of themselves and their families.

Believing, as many still do, that the human-caused extinction only got under way two or three centuries ago, in tandem, perhaps, with developments such as colonialism and the industrial revolution, allows us to view it as a recent aberration in our history.  When we assume, in addition, that this “aberration” is associated with moral failings like greed and carelessness, we’re indulging ourselves in the false comfort that we might be able to put a stop to it by making behavioral improvements that won’t disturb our current lifestyle too much.  “Want to do something for the ecology?” I read a while ago,

Unplug your mobile phone’s charger when you’re not using it, otherwise it will still bleed off a tiny trickle of electricity. That will only add pennies to your power bill, but millions of chargers left plugged in 24/7 translates into millions of kilowatt hours consumed every year. And each kilowatt hour equals about a pound of CO2 being released into the atmosphere.

Sensible advice I suppose, as far as it goes. I have to confess that I don’t usually follow it, and am of the opinion, moreover, that  anyone who sees actions on that scale as a meaningful or adequate response to our destructive impact on the planet is either ignorant or in denial.

“[I]t is natural to man,” Patrick Henry said, in his great March 20, 1775 speech to the Second Virginia Convention , “to man to indulge in the illusions of hope. We are apt to shut our eyes against a painful truth, and listen to the song of that siren till she transforms us into beasts. Is this the part of wise men, engaged in a great and arduous struggle for liberty [ecological redemption for us]? . . . For my part, whatever anguish of spirit it may cost, I am willing to know the whole truth; to know the worst, and to provide for it.”

* * *

The decline of biodiversity which occurred on almost all the earth’s continents and larger islands after each of them was settled by our species — a process that started thousands of years before the dawn of written history — has a dismayingly inexorable feel to it. If you consider that historical process in conjunction with the fact that we’re currently exterminating tens of thousands of species per year both directly and indirectly through climate change and a host of other environmental disturbances, you may well begin to doubt that there is any conceivable kind of revolution in the life of Homo sapiens that could put a stop to our seemingly inevitable destruction of the planet’s biodiversity.

While I feel, for the reasons discussed in this post, a considerable degree of ecological pessimism, I have to confess that I’m very grateful to be living in this strange, human-dominated world. My corner of that world is Canada’s Pacific coast, where human life is presently as secure as it has ever been in the history of my species. Visiting wild areas has been one of the great joys of my life, but I have no desire to travel back to the early Pleistocene to become a real participant in the wilderness ecologies I’ve marvelled at in Africa and the Americas – I wouldn’t want to be in a situation in which the planet’s biodiversity was sustained and nurtured by what looks, from my present perspective, like a terrifying degree of insecurity on a personal level.

Looking forward, then, rather than at my species’ past, my hope (slender as it is) that Homo sapiens will be able to stop eroding the planet’s biodiversity while there is still something worthwhile to save, is directed at the same phenomenon that triggered the human-caused extinction in the first place: the inventiveness of my species. Science, now the focal point of the ontological innovation we’ve been discussing in this post, has, after all, a great many achievements to its credit which, before they were published and/or demonstrated, were widely and seemingly conclusively regarded as impossible.