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| ISBN-13: | 9780190283858 |
|---|---|
| Publisher: | Oxford University Press |
| Publication date: | 09/19/2002 |
| Sold by: | Barnes & Noble |
| Format: | eBook |
| File size: | 1 MB |
About the Author
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1. Prolegomenon to a General Biology
Lecturing in Dublin, one of the twentieth century's most famous physicists set the stage of contemporary biology during the war-heavy year of 1944. Given Erwin Schrodinger's towering reputation as the discoverer of the Schrodinger equation, the fundamental formulation of quantum mechanics, his public lectures and subsequent book were bound to draw high attention. But no one, not even Schrodinger himself, was likely to have foreseen the consequences. Schrodinger's What Is Life? is credited with inspiring a generation of physicists and biologists to seek the fundamental character of living systems. Schrodinger brought quantum mechanics, chemistry, and the still poorly formulated concept of "information" into biology. He is the progenitor of our understanding of DNA and the genetic code. Yet as brilliant as was Schrodinger's insight, I believe he missed the center. Investigations seeks that center and finds, in fact, a mystery.In my previous two books, I laid out some of the growing reasons to think that evolution was even richer than Darwin supposed. Modern evolutionary theory, based on Darwin's concept of descent with heritable variations that are sifted by natural selection to retain the adaptive changes, has come to view selection as the sole source of order in biological organisms. But the snowflake's delicate sixfold symmetry tells us that order can arise without the benefit of natural selection. Origins of Order and At Home in the Universe give good grounds to think that much of the order in organisms, from the origin of life itself to the stunning order in the development of a newborn child from a fertilized egg, does not reflectselection alone. Instead, much of the order in organisms, I believe, is self-organized and Spontaneous. Self-organization mingles with natural selection in barely understood ways to yield the magnificence of our teeming biosphere. We must, therefore, expand evolutionary theory.
Yet we need something far more important than a broadened evolutionary theory. Despite any valid insights in my own two books, and despite the fine work of many others, including the brilliance manifest in the past three decades of molecular biology, the core of life itself remains shrouded from view. We know chunks of molecular machinery, metabolic pathways, means of membrane biosynthesis-we snow many of the parts and many of the processes. But what makes a cell alive is ;till not clear to us. The center is still mysterious.
And so I began my notebook "Investigations" in December of 1994, a full half century after Schrodinger's What Is Life?, as an intellectual enterprise unlike any I had undertaken before. Rather bravely and thinking with some presumptuousness :)f Wittgenstein's famous Philosophical Investigations, which had shattered the philosophical tradition of logical atomism in which he had richly participated, I retook myself to my office at home in Santa Fe and grandly intoned through my fingers onto the computer's disc, "Investigations," on December 4,1994. I sensed my long search would uncover issues that were then only dimly visible to me. I toped the unfolding, ongoing notebook would allow me to find the themes and .ink them into something that was vast and new but at the time inarticulate.
Two years later, in September of 1996, I published a modestly well-organized version of Investigations as a Santa Fe Institute preprint, launched it onto the web, and put it aside for the time being. I found I had indeed been led into arenas that I tad in no way expected, led by a swirl of ever new questions. I put the notebooks aside, but a year later I returned to the swirl, taking up again a struggle to see some:hing that, I think, is right in front of us-always the hardest thing to see. This book is the fruit of these efforts. And this first chapter is but an introduction, in brief, to :he themes that will be explained more fully in the following chapters. I would ask :he reader to be patient with unfamiliar terms and concepts.
My first efforts had begun with twin questions. First, in addition to the known laws of thermodynamics, could there possibly be a fourth law of thermodynamics For open thermodynamic systems, some law that governs biospheres anywhere in :he cosmos or the cosmos itself? Second, living entities-bacteria, plants, and animals-manipulate the world on their own behalf: the bacterium swimming upstream in a glucose gradient that is easily said to be going to get "dinner"; the paramecium, cilia beating like a Roman warship's oars, hot after the bacterium; we humans earning our livings. Call the bacterium, paramecium, and us humans "autonomous agents," able to act on our own behalf in an environment.
My second and core question became, What must a physical system be to be an autonomous agent? Make no mistake, we autonomous agents mutually construct our biosphere, even as we coevolve in it. Why and how this is so is a central subject of all that follows.
From the outset, there were, and remain, reasons for deep skepticism about the enterprise of Investigations. First, there are very strong arguments to say that there can be no general law for open thermodynamic systems. The core argument is simple to state. Any computer program is an algorithm that, given data, produces some sequence of output, finite or infinite. Computer programs can always be written in the form of a binary symbol string of 1 and o symbols. All possible binary symbol strings are possible computer programs. Hence, there is a countable, or denumerable, infinity of computer programs. A theorem states that for most computer programs, there is no compact description of the printout of the program. Rather, we must just unleash the program and watch it print what it prints. In short, there is no shorter description of the output of the program than that which can be obtained by running the program itself. If by the concept of a "law" we mean a compact description, ahead of time, of what the computer program will print then for any such program, there can be no law that allows us to predict what the program will actually do ahead of the actual running of the program.
The next step is simple. Any such program can be realized on a universal Turing machine such as the familiar computer. But that computer is an open nonequilibrium thermodynamic system, its openness visibly realized by the plug and power line that connects the computer to the electric power grid. Therefore, and I think this conclusion is cogent, there can be no general law for all possible nonequilibrium thermodynamic systems.
So why was I conjuring the possibility of a general law for open thermodynamic systems? Clearly, no such general law can hold for all open thermodynamic systems.
But hold a moment. It is we humans who conceived and built the intricate assembly of chips and logic gates that constitute a computer, typically we humans who program it, and we humans who contrived the entire power grid that supplies the electric power to run the computer itself. This assemblage of late-twentiethcentury technology did not assemble itself. We built it.
On the other hand, no one designed and built the biosphere. The biosphere got itself constructed by the emergence and persistent coevolution of autonomous agents. If there cannot be general laws for all open thermodynamic systems, might there be general laws for thermodynamically open but self-constructing systems such as biospheres? I believe that the answer is yes. Indeed, among those candidate laws to be discussed in this book is a candidate fourth law of thermodynamics for such self-constructing systems.
To roughly state the candidate law, I suspect that biospheres maximize the average secular construction of the diversity of autonomous agents and the ways those agents can make a living to propagate further. In other words, on average, biospheres persistently increase the diversity of what can happen next. In effect, as we shall see later, biospheres may maximize the average sustained growth of their own "dimensionality."
Thus, the enterprise of Investigations soon began to center on the character of the autonomous agents whose coevolution constructs a biosphere. I was gradually led to a labyrinth of issues concerning the core features of autonomous agents able to manipulate the world on their own behalf. It may be that those core features capture a proper definition of life and that definition differs from the one Schrodingerfound.
To state my hypothesis abruptly and without preamble, I think an autonomous agent is a self-reproducing system able to perform at least one thermodynamic work cycle. It will require most of this book to unfold the implications of this tentative definition.
Following an effort to understand what an autonomous agent might bewhich, as just noted, involves the concept of work cycles-I was led to the concepts of work itself, constraints, and work as the constrained release of energy. In turn, this led to the fact that work itself is often used to construct constraints on the release of energy that then constitutes further work. So we confront a virtuous cycle: Work constructs constraints, yet constraints on the release of energy are required for work to be done. Here is the heart of a new concept of "organization" that is not covered by our concepts of matter alone, energy alone, entropy alone, or information alone. In turn, this led me to wonder about the relation between the emergence of constraints in the universe and in a biosphere, and the diversification of patterns of the constrained release of energy that alone constitute work and the use of that work to build still further constraints on the release of energy. How do biospheres construct themselves or how does the universe construct itself? ...
Table of Contents
| Preface | ix | |
| 1 | Prolegomenon to a General Biology | 1 |
| 2 | The Origins of Life | 23 |
| 3 | Autonomous Agents | 49 |
| 4 | Propagating Organization | 81 |
| 5 | A Physics of Semantics? | 109 |
| 6 | Emergence and Story: Beyond Newton, Einstein, and Bohr? | 119 |
| 7 | The Nonergodic Universe: The Possibility of New Laws | 141 |
| 8 | Candidate Laws for the Coconstruction of a Biosphere | 159 |
| 9 | The Persistently Innovative Econosphere | 211 |
| 10 | A Coconstructing Cosmos? | 243 |
| Epilogue | 267 | |
| References | 271 | |
| Index | 273 |
Interviews
Essay by Stuart Kauffman
Investigations is, without a doubt, the strangest intellectual adventure of my scientific career. I began in 1994 keeping a running notebook to capture some dozen or more strands of thought, hoping they might eventually cohere into a vision of something that is right in front of us but inarticulate and virtually invisible. I hope I have succeeded. I began with a novel question: Consider a bacterium swimming upstream in a glucose gradient. We all unhesitatingly say that the bacterium is going to get food. That is, the bacterium is acting on its own behalf in an environment. I will call a system such as the bacterium able to act on its own behalf an "autonomous agent." All free-living organisms are autonomous agents. The stunning fact is that we do, every day, manipulate the universe on our own behalf. Yet nowhere in physics, or chemistry, nor yet in biology, is this fact accounted for. Further, the bacterium is "just" a physical system, and we are not vitalists. So my question became: What must a physical system be such that it can act on its own behalf, be an autonomous agent? After weeks of struggle I came to a tentative definition: An autonomous agent is a system capable of self-reproduction and also capable of carrying out one or more thermodynamic work cycles. In Investigations I work toward this definition and give a first example of a chemical autonomous agent. At a minimum, I have pointed to a new class of chemical reaction networks, ones that presage a technological revolution, for we must soon synthesize such systems, hence will soon create chemical reproducing systems that actually are able to build and construct.
It may be that I have stumbled upon an adequate definition of life itself. If so, here is the inner core, the mysterious center that has not been revealed despite the brilliance of contemporary molecular biology. Much of Investigations proceeds to study the consequences of this definition, which come to include a critique of the physicist's notion of "work," for work is, in fact, the constrained release of energy, such as a cylinder with a piston in it, where the expanding gas in the head of the cylinder does work pushing on the piston. But the catch lies in the fact that it typically takes work to construct the constraints, and the constraints to allow work to happen. Here we have a conceptual cycle, unanalyzed in physics or elsewhere that, I believe, lies at the heart of an adequate concept of organization itself. You see, a propagating microbial community is doing something that is not matter alone, energy alone, entropy alone, or information alone, but something new and undefined in current science. It is a propagating organization that builds and constructs more of itself. Investigations explores that "something," then finds and explicates a mystery at the core of life. Among the most astonishing consequences of Investigations is a conclusion I think is correct, yet one that disturbs me deeply: The way Newton, Boltzmann, Einstein, and Bohr taught us to do science may not be adequate to the persistent evolution of a biosphere. These scientists have taught us that we can prestate the space of possibilities, the configuration space, of the system being studied. But I do not think this claim holds for a biosphere. I do not think we can finitely prestate the configuration space of a biosphere. Life may be doing something nonalgorithmic, literally incalculable and persistently creative. If so, we must rethink science itself and its relation to the humanities.
Investigations explores a widening circle of issues: the physical nature of propagating organization, a strange incompleteness in the famous "Maxwell Demon" problem that raises questions about the buildup and diversification of life in a biosphere, whether autonomous agents are the minimal entities about which concepts of "value" can be applied, hence a physics of semantics, about the vastly nonrepeating character of the universe at levels of complexity of complex molecules and above, hence about the "adjacent possible" into which the biosphere and the "econosphere" persistently stumble, and whether there may be general laws governing biospheres wherever they may arise in the cosmos. Indeed, I hazard four candidate laws, including a candidate fourth law of thermodynamics for self-constructing systems such as biospheres: Biospheres, as an average, or secular trend, may become as diverse as possible, maximizing the diversity of "what can happen next." In effect, biospheres may maximize the average growth in their own dimensionality.
I go beyond these topics in Investigations to discuss both the core of economics and cosmogenesis. Caveats: I am a biologist, not an economist or a physicist. But we are routinely taught that economics is the science of the allocation of scarce resources. Yet the most stunning feature of the global economy over the past 200,000 years is the vast explosion of diversity of goods and services, from perhaps a dozen to hundreds of millions. The econosphere may also be maximizing the growth of the diversity of "what can happen next," and the main story of economics is the persistent discovery of new ways of making a living as new goods enter and old goods go extinct in "Schumpterian gales of creative destruction."
About cosmogenesis: I devote a chapter at the end to exploring parallels between self-constructing biospheres and the question of whether the cosmos as a whole co-constructs itself, including choosing the very laws that govern its behavior. This chapter is not clearly wrong but should be considered with caution.
Overall, I find Investigations deeply puzzling. I think I am correct in what I say; I think Investigations points toward dimly glimpsed issues that will come to occupy 21st-century science. I am proud of the book but remain quizzical about it. If I have opened new, useful doors, others will pass through, and this line of science will come to flourish as part of a general biology, a biology freed from the confines of terrestrial biology, and it will serve as an impetus to raise physics up to the level at which it can discuss autonomous agents, physical systems such as physicists able to manipulate the world on their own behalf.