The Coherence Of Knowledge
In an address to students at Harvard, the Pulitzer Prize-winning author and world's greatest ant scientist draws lessons from the insect world.
Thursday, February 20, 2003
I invite you this morning to consider the naturalistic world view toward which I believe scientific knowledge increasingly attracts us. In some ways it is as old as the Enlightenment of the eighteenth century and in others as new and as radical as the coming technoscientific culture of the twenty-first century.
Let me immediately lighten that proposal. I assure you I don''t mean to draw political and moral lessons from the animal kingdom. As an entomologist who has spent most of his career on hands and knees studying the highly organized and super-efficient colonies of ants, I am often asked the following question: What can human beings learn from these remarkable insects? And the answer I give with my fingers steepled, my mouth pursed, and my eyes squinted, is--Nothing. Not a thing, and it would be a major Aesopian error to believe otherwise. We can on the other hand learn certain broad principles by comparing ants with people. Professor William Morton Wheeler, my predecessor as curator in entomology at Harvard (and I paraphrase him here), has shown that social insects, like human beings, can create civilizations without the use of reason. To which I will now add my own singular discovery: despite what you might have been taught at this capitalistic university, socialism works. Karl Marx was right. He just had the wrong species.
Near-perfect six-legged socialists that ants are, let me nonetheless disabuse you of any image you have of their living in a peaceable kingdom--or more accurately, queendom, since all of the truly social castes in a colony are female. The truth is the opposite. Ants are the most warlike of all animals. Although solicitous toward their nestmates, they are murderous toward ants from other colonies. Organized territorial wars are commonplace. At your feet, if you care to look down, you will see an unmoving mass of little black ants. There before you is a formicid Agincourt, an insect Waterloo, a hymenopteran Gettysburg. The mass contains workers from two colonies recruited to the spot by scouts to a territorial boundary, locked in hand-to-hand--or perhaps I should say mandible-to-mandible--combat over contested terrain, biting and chopping off each other''s body parts. This mayhem goes on sporadically through the warm season, which in the life of an ant is roughly the equivalent period of the Thirty Years'' War.
Keep in mind on this occasion that if ants were given nuclear weapons, the world would end within a week. King Solomon was wrong when he urged, "Go to the ant, thou sluggard; consider her ways; and be wise." I agree instead with the British humorist Max Beerbohm, who wrote in his notebook some years ago, "The ant has a lesson to teach us all, and it is not good."
That disposed of, I wish you now to consider the larger and more serious issue that I raised at the beginning: What can we learn from the natural sciences, and biology in particular, about the human condition? The naturalistic world view, which I believe to be the single most important philosophical illumination science has provided, can be expressed concisely as follows: No matter how exalted we think ourselves, all that we can know and become has a material basis obedient to the decipherable laws of physics and chemistry. And no matter how intellectually far above the remainder of life we lift ourselves, and however technically proficient we become, we will stay a biological species, biological in origin, and thence adapted in mind and body to the living world that cradled us.
The persisting enigmas of the human condition--What are we? Where did we come from? What do we wish to become?--arise from two great gaps in that material comprehension. The first gap, encountered as we try to pass from biology to psychology and the social sciences, lies between brain and mind; and the second, which must be navigated from psychology to the social sciences and the humanities, is between mind and culture. For most of the modern era, these two mostly blank domains in the intellectual landscape have been taken as evidence of a permanent discontinuity between the great branches of learning--that is, the void supposedly separating the natural sciences on the one side from the social sciences and humanities on the other. It has seemed that somehow not just the vocabularies but the ways of thinking and even the very nature of truth must be forever fundamentally different between these two cultures.
Of course, many able scholars of the past have tried to create a system of thought that combined everything at some deep episte- mological level. The most concerted and valiant such effort was logical positivism, a principal focus of philosophy from the 1920s to the 1940s. These efforts all failed, just as the Enlightenment dream of intellectual unity failed, because not enough was known to traverse the gaps between brain, mind, and culture by means of cause-and-effect explanation. I believe that the matter is as simple, and formidably daunting, as that.
If the naturalistic conception is correct, the line between the great branches of learning is not a permanent epistemological break or, as a few scholars would like it, a Hadrian''s wall needed to keep the reductionist barbarians of science from high culture. It is instead a broad domain of largely unexplored phenomena awaiting cooperative exploration from both sides. That domain is now fully open to investigation. It is being penetrated at an accelerating rate by "borderland disciplines" that have begun to weave a skein of cause-and-effect explanations from brain to mind to culture, connecting the natural sciences with the social sciences and humanities. As a result, a major shift in intellectual discourse is under way.
One discipline within the borderland is cognitive neuroscience, also known as the brain sciences, which uses techniques of cell biology and brain imaging to trace the physical events of conscious experience. Another is human behavioral genetics, now closing in on the genes that affect mental and behavioral traits. A third such discipline of key importance is evolutionary biology, which is attempting to reconstruct the genetic history of human nature as it unfolded across hundreds of millennia--deep history, as it were. And finally, there are the environmental sciences, which define the physical and biological worlds to which the human body and mind have adapted during millions of years of evolution.
From the social sciences side, disciplines entering the borderland include cognitive psychology and biological anthropology. They have begun to anastomose with the natural sciences, adding to a thickening webwork of cause-and-effect explanation.
Why is this conjunction among the great branches of learning important? Because it offers the prospect of characterizing human nature with greater objectivity and precision, an exactitude that is the key to human self-understanding. The intuitive grasp of human nature has been the substance of the creative arts. It has been the underpinning of the social sciences, and it is a beckoning mystery to the natural sciences. To grasp it objectively, and explore it to its depths scientifically, would be to approach if not attain the grail of scholarship, and fulfill the dreams of the Enlightenment.
Rather than let the matter hang in the air rhetorically, I will be so bold--some would say reckless--as to suggest a preliminary definition of human nature, as follows. Human nature is not the genes, which prescribe it. It is not the cultural universals, such as the incest taboos and rites of passage--they are the products of human nature. Rather, human nature is the epigenetic rules, the inherited regularities of mental development. These rules are the genetic biases in the way our senses perceive the world, the symbolic coding by which we represent the world, the options we open to ourselves, and the responses we find easiest and most rewarding psychologically to make. In ways that are beginning to come into focus at the physiological and, in a few cases, the genetic level, the epigenetic rules alter the way we see and linguistically classify color, for example. They cause us to evaluate the aesthetics of artistic design according to degree of complexity. They lead us differentially to acquire fears and phobias concerning dangers in the environment (as from snakes and heights), they induce us to communicate with certain facial expressions and forms of body language, to bond with infants, and so on across a wide range of categories in behavior and thought. Most, like incest avoidance, are evidently very ancient, dating back millions of years in mammalian ancestry. Others, such as the stages of linguistic development, are uniquely human and probably only hundreds of thousands of years old.
I know that the conception of a biological foundation of complex social and cultural structures runs against the grain for many scholars. They object that too few such inherited regularities have yet been found to make the case solid, and in any case higher mental processes and cultural evolution are too complex, shifting, and subtle to be usefully reduced in such a way. But the same was said by the vitalists about the nature of life when the first enzymes and other complex organic molecules were discovered. The same was declared about the physical basis of heredity even as early evidence pointed straight to the relatively simple DNA molecule as the carrier of the genetic mode. And most recently, doubts about the accessibility of the physical basis of mind are fading before the successes of sophisticated imaging techniques. In the history of the natural sciences a common sequence has predictably unfolded as follows. An entry point to a complex system is found by analytic probing. At first one and then more paradigmatic reductions are achieved. Examples are multipled as the whole system opens up and its architecture is disclosed. Finally, in retrospect, with the mystery at least partly solved, the cause-and-effect explanations seem obvious, even inevitable.
The value of the consilience program--or renewal of the Enlightenment agenda if you prefer that expression--is that at long last we appear to have acquired the means either to establish the truth of the fundamental unity of knowledge, or to discard the idea. I believe we will establish it. The great branches of learning will meet this way, and if so it will be a historic event that happens only once. But be careful: surprises, even shocking surprises, may occur. What will be the outcome? Keep your finely trained minds and proven high intelligence focused, as together we find out.