doi:10.1038/7145
March 1999 Volume 17 Supplement pp BV3 - BV4
Understanding science and knowing ignorance
François Jacob1
1. François Jacob is professor of cellular genetics, Institut Pasteur, 25, rue du Dr Roux, 75724, Paris Cedex 15, France
(e-mail: fjacob@pasteur.fr ).
2. Excerpt from Of Flies, Mice, and Men, by François Jacob, translated by Giselle Weiss, published in February 1999 by Harvard University Press, ©1998 by the President and Fellows of Harvard College. Originally published as La Souris, la mouche et l'homme, Editions Odile Jacob, ©1997. Reprinted by permission of Harvard University Press.
As this century draws to a close, the "future" business is flourishing in Western society. In France, some forty thousand seers, soothsayers, psychics, and other fortune tellers collect, annually, a sum of several tens of billions of francs. Nearly one in ten Frenchmen, including many of our political leaders, seems to be behaving like the king of the Iliad, consulting his favorite psychic more or less regularly.
At the same time, so strong is public confidence in the predictive capability of science, that seers and psychics do not hesitate to describe their predictions as "scientific," the better to lure clients.
And seers and psychics have no monopoly on this confidence. Every year symposia are organized on futurist themes of the genre "What will biology be like in twenty years?" or "Medicine in the twenty-first century" or "What will the effects of science on society be at the beginning of the next century?" People who choose these subjects enjoy the call of the open sea. They want to open up new routes, offer unlimited prospects into which a tractable future will fit quite naturally. Indeed, politicians and administrators of science cannot bear the idea of blind research that gropes along with no guarantee of results. Since they are supposed to be directing research, at the very least they have a duty to steer it toward some destination. They long to participate in this great human adventure. And for them, making plans, sketching out a direction, and speaking of the future is tantamount to mastering it.
Yet science is also unpredictable. Research is an endless process; we can never say how it will evolve. Unpredictability is part of the very nature of the scientific enterprise. If what we are going to find out is truly new, then it is by definition something we cannot know in advance. There is no way to say where a given field of research will lead. This is why we cannot choose certain aspects of science and reject others. As Lewis Thomas points out, either you have science or you don't. And if you have it, you can't take only what you like. You also have to accept those aspects of it that are surprising and disturbing.
This aspect of unpredictability shows up clearly throughout the history of science. Who would have said in 1850, before Pasteur and Koch, that infectious diseases would turn out to be the result of invasion by specific germs? Or in l950, before the work of Watson and Crick, that the chemistry of heredity would be understood before that of muscle tissue? And this unpredictability holds not only for basic research but for its applications. If during the Stone Age people had wanted to develop tools for cutting and slicing, they would have produced stone axes in various shapes and at various prices, but they would never have discovered bronze. Or if, at the end of the nineteenth century, people had wanted to improve methods of locating fragments of projectiles left in wounds, they would have produced all kinds of probes, of all sizes, made from various materials, but they would never have been able to predict the existence and use of X-rays.
Political foresight
Although it may sometimes be hard to believe, great politicians are capable of clear vision, even in matters of science. When he returned to public life in 1958, Charles De Gaulle appointed a committee of twelve "wise men," each representing a scientific discipline, to advise him. At the end of the year he decided to choose several areas of research which, owing to their compelling interest, would receive special funding. He assembled the twelve wise men and gave each of them five minutes to present an area of research that seemed especially worth supporting. And so they did. Raymond Lararjet, [one of the wise men] proposed "molecular biology". At the end of the hour, there was silence. De Gaulle spoke:
You might think that a general would be particularly appreciative of spectacular projects whose descriptions he understands, whose perspective he shares, and whose developments, consequences and repercussions he readily anticipates. Examples among those I've just heard would be renewable energy resources, the conquest of space, and the exploitation of the oceans. But deep down, I wonder whether this mysterious molecular biology, of which I know nothing and will certainly never understand anything, isn't the most promising of the mid-term developments—unpredictable, rich, capable of doing much to advance our understanding of the basic phenomena of life and its disorders. Perhaps it will be the basis for a new medicine that we cannot even imagine today. It might even be the medicine of the twenty-first century.
And molecular biology was the first choice of the committee. What an astonishing vision of the future!
Common roots
From its inception at the beginning of the nineteenth century, biology was preoccupied with structure and function. Despite the clamor of those who argued for the indivisibility of living beings, reductionism achieved victory after victory. Yet the deeper biology probed differences among organisms, the more they faded away, affirming a unity of living things. In the middle of the last century, study of the cell revealed the structural unity, in a sense, the atom, of life. Next came the theory of evolution, and with it a common origin. Before the Second World War, biochemists demonstrated the commonalities of structure and function underlying the diversity of life forms. From the 1960s onward, molecular biology provided evidence for the unity of genetic systems and the basic mechanisms that regulate cell function. And finally, with the advent of genetic engineering in the 1970s, the unity of the living world was proven to a point not previously imaginable. All the creatures that inhabit this earth, whatever their environment, size, or means of subsistence—snail, lobster, fly, or giraffe—all turn out to be made from molecules that are more or less identical. And likewise, from yeast to humans, there are groups of closely related molecules that serve to assure universal life functions, such as cell division or signaling between the cell membrane and the nucleus.
So now a fantastic paradox emerges: organisms of the most different sorts are constructed from the very same battery of genes. The diversity of life forms results from small changes in the regulatory systems that govern the expression of these genes. The structure of the adult organism is determined by the development of the embryo. If, during that development, a gene is expressed a little earlier or a little later, or if it functions more abundantly in slightly different tissues, the final product, the adult animal, will be profoundly modified. Which is how it happens that, despite their enormous differences, fish and mammals have approximately the same genes, just as do crocodiles and sparrows.
Uncommon perception
Scientists have taken understanding of the world and the universe far beyond the range of normal human experience. Our senses and our brains were not selected to perceive the properties of electrons or the distances that separate galaxies or cosmological time, but to deal with the world around us—objects, space, and time—on the scale of human beings. To imagine what came before or what will happen after, we have to trick ourselves; and it is not certain that we will ever manage to reconstruct what really happened.
As Claude Levi-Strauss pointed out with obvious satisfaction, the accounts that science ultimately resorts to are as removed from common sense as the products of mythological thought. When we think about the origin of life, we have to accept that, over the course of some eight or nine hundred million years, thousands of events, each highly improbable, followed one after the other to permit the transformation of an earth without life to life in a RNA world, and then to life in a DNA world. Clearly, such a history might appear as incomprehensible to non-initiates as do the stories of Creation in the Theogony of Hesiod, the Upanishads, or the Bible. Indeed, mythological tales seem closer to common sense than does the discourse of biochemists and molecular biologists.
Misconception and misanthropy
Biological scientists have not taken a lead in advancing human understanding. They are out in front, undoubtedly. Many would-be followers have lost sight of them and of science. We should not forget what the outcome of this can be. In this era of genetic engineering, the Human Genome Project, embryonic research, and sociobiology, we cannot forget. It is not possible to act as if nothing happened in the camps of Nazi Germany.
What matters here is not the role of the physician who performed what he called "experiments" in the camps. It is that of the scientist who inspired the theory. It is the responsibility of those who advanced the doctrine on which the crudest possible version of biological determinism was founded. With the wisdom of hindsight, it is easy today to recognize that most of the ideas that inspired the eugenics movement were unjustified. Yet many of its followers were perfectly respectable men of science who thought they were acting in the public interest. So where did they go wrong?
Where they went wrong was in not examining critically enough the very concept of eugenics and what it implied. In particular, they did not correctly evaluate its social consequences. The danger for the scientist is to not test the limits of his science, and thus of his knowledge. It's to mix what he believes and what he knows. And especially, it's the certainty of being right. Geneticists did not adequately expose their ideas about eugenics to non-scientists. They were not sufficiently in contact with the rest of society before proposing a doctrine whose application would profoundly affect society.
Moreover, scientists often work with abstractions, with concepts. To proceed with his analysis, the biologist must often dismantle the organism he wants to study. He is interested in an "object," "system"—organ, tissue, cell type, protein, gene, and so on. An object has no dignity. It has no rights. You can do what you want with it without asking its leave. Working with human beings is not at all the same. No experiment of any kind should be tried on human beings without their consent. The respect for and dignity of the human person must be preserved in all circumstances. Even when he is himself the object, the human being must remain the subject.
It has occasionally been suggested that we pursue only "good" research, research that is supposed to bring only benefits to the human species, and that we abandon "bad" research, that is, research that might cause problems. You would have to misunderstand what science is to make such a suggestion. Research is a never-ending process whose evolution we cannot predict. Another suggestion is sometimes made: stop genetic research. It will open doors that should not be opened: doors behind which may lie findings that could, for example, risk increasing racial tensions. This reminds us of Adam or Prometheus.
But it is not knowledge that is dangerous, it is ignorance. And it is hard to imagine, given all the cultural, political, and religious— not to mention scientific— differences, what power would be in a position to close all the genetics laboratories in the world. Moreover, it would mean cutting ourselves off not only from "bad" genetics but also from "good genetics." In the future our medicine will be largely based on genetics. After the Second World War, for purely ideological reasons and totally disregarding thirty years' worth of scientific data acquired from all over the world, the Soviets decided that genetics was a bourgeois science to be banished from Communist countries. On Stalin's orders, genetics was replaced by the lunatic theories of Lysenko. The results are well known: for several decades, the development of biology and its application, both in agriculture and in medicine, was totally blocked in East European countries. They are still recovering from it.
Science for humanity
Science has become the source of all the elements of contemporary technology: those we like, such as airplanes, television, penicillin, birth control, and those we detest, such as thermonuclear bombs, pesticides, and many kinds of pollution. Three hundred years is not a very long time. But it is long enough to try to evaluate the process, to decide whether this approach has served humankind or not. On this subject, there has been some disagreement. From the beginning, voices have sounded in opposition. Voices that cry out, "Let's go back! Let's find another system, something less dangerous to the human species!" Of course, scientists have a different perspective.
Biology, for example, is in its infancy. It has only just begun to exist, bringing in its wake a nascent medicine. What is on the horizon, if basic research efforts are sustained, is not only the control of many diseases or agricultural improvements. With a better grasp of the fundamental processes of the living world, we can hope to learn more about ourselves. We desperately want to know who we are, where we come from, and what are we doing here. Granted, science cannot answer all questions. It can, however, give some indications, exclude certain hypotheses. Engaging in the pursuit of science may help us make fewer mistakes. It's a sort of gamble. But our alternatives are not so many. Moreover, today, we number five billion. Tomorrow, we will number six billion. The day after tomorrow, twenty. Terrible problems lie in store for humankind. There, too, the pursuit of science appears indispensable in the search for solutions.
The main discovery during this century of research and science has probably been the depth of our ignorance of nature. The more we learn, the more we realize the extent of our ignorance. That in itself is major news. For the first time, we can face up to our ignorance. For a long time we claimed to understand how things worked or we simply made up stories to plug the gaps. Now that we have seriously begun to study nature, we have a better idea of the breadth of the questions, of the distance we must go to begin to answer them.+++++++++++>
http://www.nature.com/cgi-taf/DynaPa...399supp_3.html