Dyson on origins of life
- Rather than enter into another fruitless debate with Steve challenging his trivially true/patently false belief that
humans are not able to "transcend" their genes, I thought it would be worth posting this short piece by the ever
thought provoking Freeman Dyson concerning his speculations as to the relevance of this question at the start of life.
EDITOR'S INTRODUCTION | Are the workings of science and culture a subtle reflection of human biology? Are we simply prisoners of our self-replicating genes, or do our lives manifest a reality that is far more complicated? The distinguished scientist Freeman Dyson raises these eternal questions, and draws on his own experiences in his attempt to forge an answer.
t the end of his book What is Life? (1944), Erwin Schrödinger put a four-page epilogue with the title "On determinism and free will." He there states his personal philosophical viewpoint, his reconciliation between his objective understanding of the physical machinery of life and his subjective experience of free will. He writes with a clarity and economy of language that have rarely been equaled. I will not try to compete with Schrödinger in summing up in four pages the fruits of a lifetime of philosophical reflection. Instead I will discuss some of the wider implications of our thoughts about the origin of life, not for personal philosophy but for other areas of science. I use the word science here in a broad sense, including social as well as natural sciences. The sciences that I have particularly in mind are ecology, economics, and cultural history. In all these areas we are confronting the same question that is at the root of the problem of understanding the origin of life: Why is life so complicated? It may be that each of these areas has something to learn from the others.
The economist Adam Smith (1723-90), the author of The Wealth of Nations. His ideas influenced Darwin in working out the theory of evolution.
The tendency toward equilibrium
The concept of homeostasis (defined as the machinery of chemical controls and feedback cycles that make sure that each molecular species in a cell is produced in the right proportion) can be transferred without difficulty from a molecular context to ecological, economic, and cultural contexts. In each area we have the unexplained fact that complicated homeostatic mechanisms are more prevalent and seem to be more effective than simple ones. This is most spectacularly true in the domain of ecology, where a typical stable community, for example a few acres of woodland or a few square feet of grassland, comprises thousands of diverse species with highly specialized and interdependent functions. But a similar phenomenon is visible in economic life and in cultural evolution. The open market economy and the culturally open society, notwithstanding all their failures and deficiencies, seem to possess a robustness that centrally planned economies and culturally closed societies lack. The homeostasis provided by unified five-year economic plans and by unified political control of culture does not lead to a greater stability of economies and cultures. On the contrary, the simple homeostatic mechanisms of central control have generally proved more brittle and less able to cope with historical shocks than the complex homeostatic mechanisms of the open market and the uncensored press.
Lessons from Darwin
But I did not intend this to be a political manifesto in defense of free enterprise. My purpose in mentioning the analogies between cellular and social homeostasis was not to draw a political moral from biology but rather to draw a biological moral from ecology and social history. Fortunately, I can claim the highest scientific authority for drawing the moral in this direction. It is well known to historians of science that Charles Darwin was strongly influenced in his working out of the theory of evolution by his readings of the political economists from Adam Smith to Malthus and McCullough. Darwin himself said of the theory: "This is the doctrine of Malthus applied to the whole animal and vegetable kingdom." What I am proposing is to apply in the same spirit the doctrines of modern ecology to the molecular processes within a primitive cell.
In our present state of ignorance we have a choice between two contrasting images to represent our view of the possible structure of a creature newly emerged at the first threshold of life. One image is the hypercycle model of Manfred Eigen, with molecular structure tightly linked and centrally controlled, replicating itself with considerable precision and achieving homeostasis by strict adherence to a rigid pattern. The other image is the "tangled bank" of Darwin, an image that Darwin put at the end of his Origin of Species to make vivid his answer to the question, What is life?, an image of grasses and flowers and bees and butterflies growing in tangled profusion without any discernible pattern, achieving homeostasis by means of a web of interdependences too complicated for us to unravel.
The tangled bank is the image that I have in mind when I try to imagine what a primeval cell would look like. I imagine a collection of molecular species that are tangled and interlocking like the plants and insects in Darwin's microcosm. This was the image that led me to think of error tolerance as the primary requirement for a model of a molecular population taking its first faltering steps toward life. Error tolerance is the hallmark of natural ecological communities, of free market economies, and of open societies. I believe it must have been a primary quality of life from the very beginning. But replication and error tolerance are naturally antagonistic principles. That is why I like to exclude replication from the beginnings of life, to imagine the first cells as error-tolerant tangles of nonreplicating molecules, and to introduce replication as an alien parasitic intrusion at a later stage. Only after the alien intruder has been tamed is the reconciliation between replication and error tolerance achieved in a higher synthesis through the evolution of the genetic code and the modern apparatus of ribosomes and chromosomes.
The modern synthesis reconciles replication with error tolerance by establishing the division of labor between hardware and software, between the genetic apparatus and the gene. In the modern cell, the hardware of the genetic apparatus is rigidly controlled and error intolerant. The hardware must be error intolerant to maintain the accuracy of replication. But the error tolerance that I like to believe was inherent in life from its earliest beginnings has not been lost. The burden of error tolerance has merely been transferred to the software. In the modern cell, with the infrastructure of hardware firmly in place and subject to a strict regime of quality control, the software is free to wander, to make mistakes, and occasionally to be creative. The transfer of architectural design from hardware to software allowed the molecular architects to work with a freedom and creativity that their ancestors before the transfer could never have approached. A similar transfer of architectural design from embryo to adult probably caused the outburst of evolutionary novelty that we call the Cambrian explosion.
The analogies between the genetic evolution of biological species and the cultural evolution of human societies have been brilliantly explored by Richard Dawkins in his book The Selfish Gene (1976). The book is mainly concerned with biological evolution. The cultural analogies are pursued only in the last chapter. Dawkins's main theme is the tyranny that the rigid demands of the replication apparatus have imposed upon all biological species throughout evolutionary history. Every species is the prisoner of its genes and is compelled to develop and to behave in such a way as to maximize their chances of survival. Only the genes are free to experiment with new patterns of behavior. Individual organisms must do what their genes dictate. This tyranny of the genes has lasted for 3 eons and has been precariously overthrown only in the last hundred thousand years by a single species, Homo sapiens. We have overthrown the tyranny by inventing symbolic language and culture. Our behavior patterns are now to a great extent culturally rather than genetically determined. We can choose to keep a defective gene in circulation because our culture tells us not to let hemophiliac children die. We have stolen back from our genes the freedom to make choices and to make mistakes.
In his last chapter Dawkins describes a new tyrant that has arisen within human culture to take the place of the old. The new tyrant is the "meme," the cultural analogue of the gene. A meme is a behavioral pattern that replicates itself by cultural transfer from individual to individual instead of by biological inheritance. Examples of memes are religious beliefs, linguistic idioms, fashions in art and science and in food and clothes. Almost all the phenomena of evolutionary genetics and speciation have their analogues in cultural history, with the meme taking over the functions of the gene. The meme is a self-replicating unit of behavior like the gene. The meme and the gene are equally selfish. The history of human culture shows us to be as subject to the tyranny of our memes as other species are to the tyranny of genes. But Dawkins ends his discussion with a call for liberation. Our capacity for foresight gives us the power to transcend our memes just as our culture gave us the power to transcend our genes. We, he says, alone on earth, can rebel against the tyranny of the selfish replicators.
Simplicity or complexity?
Dawkins's vision of the human situation as a Promethean struggle against the tyranny of the replicators contains important elements of truth. We are indeed rebels by nature, and his vision explains many aspects of our culture that would otherwise be mysterious. But his account leaves out half the story. He describes the history of life as the history of replication. Like Eigen, he believes that the beginning of life was a self-replicating molecule. Throughout his history, the replicators are in control. In the beginning, he says, was simplicity. The point of view that I am expounding is precisely the opposite. In the beginning, I am saying, was complexity. The essence of life from the beginning was homeostasis based on a complicated web of molecular structures. Life by its very nature is resistant to simplification, whether on the level of single cells or ecological systems or human societies.
Life could tolerate a precisely replicating molecular apparatus only by incorporating it into a translation system that allowed the complexity of the molecular web to be expressed in the form of software. After the transfer of complication from hardware to software, life continued to be a complicated interlocking web in which the replicators were only one component. The replicators were never as firmly in control as Dawkins imagined. In my version the history of life is counterpoint music, a two-part invention with two voices, the voice of the replicators attempting to impose their selfish purposes upon the whole network and the voice of homeostasis tending to maximize diversity of structure and flexibility of function. The tyranny of the replicators was always mitigated by the more ancient cooperative structure of homeostasis that was inherent in every organism. The rule of the genes was like the government of the old Hapsburg Empire: Despotismus gemildert durch Schlamperei, or "despotism tempered by sloppiness."
As the grandfather of a pair of five-year-old identical twins, I see every day the power of the genes and the limits to that power. George and Donald are physically so alike that in the bathtub I cannot tell them apart. They not only have the same genes but have shared the same environment since the day they were born. And yet, they have different brains and are different people. Life has escaped the tyranny of the genes by evolving brains with neural connections that are not genetically determined. The detailed structure of the brain is partly shaped by genes and environment and is partly random. Earlier, when the twins were two years old, I asked their older brother how he tells them apart. He said, "Oh, that's easy. The one that bites is George." Now that they are five years old, George is the one who runs to give me a hug, and Donald is the one who keeps his distance. The randomness of the synapses in their brains is the creative principle that makes George George and Donald Donald.
One of the most interesting developments in modern genetics is the discovery of "junk DNA," a substantial component of our cellular inheritance that appears to have no biological function. Junk DNA is DNA that does us no good and no harm, merely taking a free ride in our cells and taking advantage of our efficient replicative apparatus. The prevalence of junk DNA is a striking example of the sloppiness that life has always embodied in one form or another. It is easy to find in human culture the analogue of junk DNA. Junk culture is replicated together with memes, just as junk DNA is replicated together with genes. Junk culture is the rubbish of civilization: television commercials, Internet spam, astrology, and political propaganda. Tolerance of junk is one of life's most essential characteristics. I would be surprised if the first living cell had not been at least 25 percent junk.
In every sphere of life, whether cultural, economic, ecological, or cellular, the systems that survive best are those that are not too fine-tuned to carry a large load of junk. And so, I believe, it must have been at the beginning. The early evolution of life probably followed the same pattern as the development of the individual human brain, beginning with a huge assortment of random connections and slowly weeding out by trial and error the connections that made no sense. George and Donald are different people because they started life with different random samples of neurological junk in their heads. The weeding out of the junk is never complete. Adult humans are only a little more rational than five-year-olds. Too much weeding destroys the soul.
- He does make one point:
culture tells us not to let hemophiliac children die.We have stolen back from our genes the freedom to make choices and to make mistakes. <> We can choose to keep a defective gene in circulation because ourIn other words, we can diminish the lives of unknown numbers of people yet unborn to make ourselves feel righteous."to make mistakes"How charming; we can destroy the 'life work' of thousands of generations (and poison the genome of our kindred) to manifest a delusional morality, and if we make mistakes, isn't our freedom marvelous.Talk about narsisstic.RAF
- RAF,Let me suggest we need to make the distinction here between not letting the child die and not letting it reproduce. It's the reproduction that keeps the genes in circulation. Basically eugenics is a slippery, though in this human overpopulated world a necessary, slope.And of course the deleterious effects on the planet are caused primarily by upbringing, not by genetic makeup. It would be much more reasonable and effective simply to not let those types who destroy our society and our planet to reproduce wouldn't it? There is a long list of candidates: Feminists, religionists, 'sport' hunters, military types, politicians just for starters.... After all it is the children of such types most likely to be raised to perpetuate their parents destructive effects.EdgarOn Oct 10, 2009, at 12:35 PM, R A Fonda wrote:He does make one point:> We can choose to keep a defective gene in circulation because our culture tells us not to let hemophiliac children die.We have stolen back from our genes the freedom to make choices and to make mistakes. <In other words, we can diminish the lives of unknown numbers of people yet unborn to make ourselves feel righteous."to make mistakes"How charming; we can destroy the 'life work' of thousands of generations (and poison the genome of our kindred) to manifest a delusional morality, and if we make mistakes, isn't our freedom marvelous.Talk about narsisstic.RAF