15 The Future of the Hand

The existence of human intelligence poses an evolutionary puzzle—not because it is so impressive but because it is unique. Why has it not evolved in more species? By “intelligence” I here mean to encapsulate toolmaking, language, social organization, and the cognitive abilities associated with these things (call this constellation of traits Intelligence). It is obvious that this adaptation confers great power on its possessor—so why has no other species managed to evolve the adaptation? For adaptations like locomotion, eyesight, and a sense of smell, the utility of the trait has led to multiple occurrences across the animal kingdom—some due to inheritance from a common ancestor, some instances of convergent evolution. Isn’t Intelligence at least as useful a trait as these? Why isn’t it everywhere? This is puzzling—as if only one species among millions had ever evolved eyesight. Why, in particular, is language unique to the human species (the kind of advanced language humans possess)? If there is life on other planets, is there much Intelligence there? Forget the idea that humans are somehow at the predestined pinnacle of creation, toward which the universe has always been tending; our special traits are as accidental as any. It is not that the universe has been working toward producing Intelligence all along and picked us alone as its proud bearer. It might never have evolved at all.

The answer must be that Intelligence is simply not an accessible trait for other species. But why is that? No doubt it would benefit them greatly if they had it, but there is no platform in their current condition (nor in their past condition) from which it can be naturally reached. It exists in logical adaptive space for many creatures, but in empirical reality it has only evolved once on planet Earth. But why do other species lack the necessary preadaptive platform? What did we have prior to our development of Intelligence that they don’t have? What did early man harbor in his biological makeup that made Intelligence possible for him?¹

It would be a mistake to summarize the thesis of this book by saying that he had a tree-adapted hand. That is obviously not sufficient, because our primate relatives also have tree-adapted hands (and have had for a long time), but they lack Intelligence. Rather, it was the forced descent of this hand from the trees that was the decisive factor: the liberation of the hand from locomotion duties, the subsequent development of tools, and so on. It was the modifications to the arboreal hand, occasioned by the descent, which made the difference (the elongated thumb, in particular). The Transition occurred because the hand had to adapt to terrestrial life, along with the brain. Fortunately, it was capable of the kinds of transformations required, these being essentially incremental (mainly the gradual lengthening of the thumb). Ground-dwelling species in general don’t have hands, only arboreal species do; so terrestrial animals never developed Intelligence—as persistently arboreal species never do either. It was the combination of possessing an arboreal hand and being relocated to a terrestrial setting that set the stage for Intelligence—the odd confluence of these circumstances. It was the mismatch between body and niche that provided the essential preadaptation—the fish-out-of-water aspect of the whole thing. The route to Intelligence went through the freak accident of an arboreal hand no longer doing arboreal work. It went through the fact that the hand had been made pretty much redundant—and hence available for other types of labor. It is as if the world went completely dark, so that eyes were no longer functional, but accidentally nature found a new unrelated use for eyes—as it might be, using them as flotation devices, or making sounds with the eyelids. Imagine if such a peculiar train of events led to the world domination of the species that discovered this new use for eyes: then that is a bit like what happened with us. The explanation of our species success resides in the unlikely redeployment of an organ stripped of its original function, namely tree clinging and brachiation. The success arises, fundamentally, from the disenfranchisement of the hand, not from its continued use in its natural environment. On the ground, natural selection operated much more harshly than it had in the trees, and the result was a rapid change of phenotype that led ultimately to Intelligence.

Now we can see just how improbable the evolution of Intelligence was. It required a remarkable confluence of unrelated circumstances. There is nothing natural or inevitable or even vaguely foreseeable about it. It is not that any hand, in the fullness of time, will naturally power the growth of Intelligence. It just so happened that our tree-adapted hand, forced into the alien terrestrial niche, and after some minor anatomical tinkering, proved to contain the preadaptations necessary for tool use and language—though these traits were certainly not written into its original design. This is surely a virtually unrepeatable set of circumstances. Throughout the course of evolution all species have got by without the aid of Intelligence; we alone evolved the trait. And the reason we did so is not the kind of thing that naturally repeats itself. Unless something analogous has occurred on other life-bearing planets, which seems very improbable, we may expect to find a distinct lack of Intelligence distributed throughout the universe. The circumstances under which we acquired Intelligence are just so improbable in themselves that they are unlikely to be repeated. Our biological line would never have developed the trait if it weren’t for the descent from the trees, combined with the antecedent structure of the primate hand. That we did develop it was just a monstrous piece of blind good luck (based on bad luck). Thus we see the answer to our puzzle: Intelligence is unique because the preconditions that led to it are virtually unrepeatable.² Indeed, our theory of the emergence of Intelligence is confirmed by the very fact of its uniqueness. Any theory of that emergence needs to be able to account for its uniqueness. How often has evolution thrown up a case of dispossessed hands? Unless this odd scenario is repeated on other planets—and why should it be?—humans may be the only species ever in the universe to evolve Intelligence.

You might think that Intelligence could arise from some other cause—it might be able to arise under a variety of conditions. In principle that is possible, but it is striking that it has not in fact ever arisen from any other cause on Earth. Maybe a species on another planet has evolved it as an answer to some other pressing need and on the basis of a different anatomical endowment—say, in order to negotiate labyrinthine pathways and mediated by extremely complex eyes. This species, we may suppose, has no hands and has never been ejected from its ancestral habitat, yet it evolved Intelligence nonetheless. Maybe—but on planet Earth the lines of evolutionary development seem to preclude any route to Intelligence except the route followed by humans.³ No birds, reptiles, or even other primates, have found a way to acquire the trait, despite its utility; and we have it only because of an oddity of contingent evolutionary history. Our status as Homo sapiens rests on a freak historical event, a wildly unlikely series of accidents. In no way were we ever destined to become Intelligent. It was entirely possible that the complete history of life on Earth, from its first glimmerings to its eventual total extinction, extending over billions of years, should have never produced a species with Intelligence. As things are, it has done so only once, despite eons of time in which to stumble on the adaptation, and despite the existence of millions of distinct species. So this adaptation is quite unlike other adaptations such as locomotion and eyesight, which are quite predictable from the general conditions of life on Earth—which is why they are so widespread. Intelligence deserves to be called a “singularity.”

As Darwin remarked, we are clever because we are feeble.⁴ We might even say that we are unnaturally clever because we are naturally feeble. Our cleverness is a kind of compensation for a lack of natural power. Without brawn, you must develop brain. Cleverness is our adaptation for not being well adapted—to ground living, life under (not in) the elms. But cleverness—a big brain—is pointless unless it is harnessed to a body capable of making use of it. The hands are the primary bodily means whereby we manifest our cleverness. No other organ comes close to the hands as an instrument of intelligent action. The hands are capable of expressing every nuance of our intelligence. They have, as I have repeatedly remarked, served us well. They saved us from extinction and gave us comfortable homes and personal security—as well as the delights of culture. But will they continue to occupy center stage in human existence? What is their evolutionary future?

It is hard to see how the hands could become obsolete, given their role in the operation of technology. Manual skills of traditional kinds may fall away, as work becomes ever more automated. Penmanship has surely had its day. But surely the hands will be necessary for the conduct of daily life far into the future (the legs will be obsolete sooner). I can envisage just one way in which the hand may become a thing of the past, withering into a useless appendage. That is by the invention of direct neural manipulation: issuing orders straight from the brain into the tool we wish to use. This would require a device, attached to the head, which translates neural signals into electromagnetic energy that is then transmitted to an input module on the instrument we wish to manipulate—willing things to move, in effect. Thus we could drive our cars without laying a hand on the wheel, engage in hands-free cooking, and knock in a nail without holding a hammer.

But this is a narrow utilitarian view of the function of the human hand: we would still want to use it for purposes of play and social relations, would we not? The only threat to this that I can envisage is some new form of zealotry that regards the hand as offspring of the Devil and prohibits its employment. Given that the brain transducer has made the hand obsolete for work, this anti-hand zealotry might succeed in banning its use elsewhere. I can imagine a futuristic science fiction story, of dystopian tendency, being written around the theme: Doom of the Hand. It might prove an instructive tale. But if such a thing ever came to pass in reality, it would surely be a great tragedy for the human race. It would, I suspect, cause a sickness of the soul far greater than any technological or social change yet inflicted on us. It would be the end of the human race as we know it.⁵ For that reason I doubt such a thing could ever come to pass. The hand will live on.

Although I don’t think the hand is an endangered species, I do think we should regard it with greater reverence than we are apt to. We should give it the credit it deserves. This is why (with tongue in cheek) I advocate forming a “Cult of the Hand” to raise its profile. The cult will celebrate the hand in all its glory, acknowledge its achievements, and seek to improve hand awareness and hand health. This book might then be viewed as a text to motivate and underpin the formation of such a cult. I therefore cordially invite my readers to join the Cult of the Hand.