Reviewed by Dr. Tony Rogers
By Stuart A. Kauffman. New York: Oxford University Press, 2000. 336 pages, indexes. Hardcover; $30.00.
Why, in spite of entropy, nature’s imperative to overall disorder, does life on Earth become so much more complex and biochemically diverse as time passes? Investigations asks this question while attempting to bring Stuart Kauffman’s concepts of self-organization into mainstream science. A recipient of the Mac Arthur Fellowship, Kauffman has one of the keenest minds in the naturalist camp. He is a founding member of the Santa Fe Institute, where he conducts research into the emerging science of complexity. His more well known books include The Origins of Order and At Home in the Universe.
Though it addresses the question of increasing complexity, Investigations contains views that are speculative and often incomplete. Kauffman himself terms the book’s subject matter “proto-science.” In this context, Kauffman proposes a new “fourth law of thermodynamics” that governs the actions of autonomous agents. Within this framework, he explores the origin of life from complex reaction networks, the coevolution of autonomous agents in biospheres, the operation of complex economies, and even the development of the cosmos. The overarching principle governing these seemingly disparate processes is termed the “adjacent possible,” which Kauffman describes as those things one step away from what currently exists. The book offers an example of a mixture of precursor molecules one reaction step away from forming a set of more complex organic molecules.
The origin-of-life question has clearly driven Kauffman’s scientific inquiries, particularly in view of the scant progress made by evolution’s advocates. Kauffman notes that Watson-Crick base-pairing in polynucleotides (such as the “RNA world” model) is the prevailing view of how self-replication began in the molecular world. However, subsequent efforts to synthesize such a system capable of self-replication have failed. Not deterred, Kauffman brings the concepts of autocatalysis, self-organization, and the “adjacent possible” to bear on the origin-of-life problem. He considers it likely, if not obvious, that self-reproducing molecular systems will spontaneously form in any large and sufficiently complex chemical reaction mixture.
Kauffman proposes an alternative model for the origin of life: a self-reproducing peptide system. In this model, no molecule would catalyze its own formation, but the system would collectively catalyze its own formation from smaller peptides. Investigations takes the potential for collective autocatalysis in complex peptide systems to be all but inevitable. However, the book never suggests how such a reaction system would spawn a genetic code or isolate itself within a membrane to sustain displacement from equilibrium. Kauffman has no ready answers to these questions at this stage of his research.
Given his assertion that life has “bootstrapped” its way into existence, Kauffman follows through with some novel ideas about the development of a biosphere. He views the proliferation of life forms in Earth’s biosphere as the natural tendency of existing entities to self-organize and coevolve into structures of increasing complexity, each agent altering the fitness landscape of the rest. But why should Earth’s biosphere become more diverse chemically as time passes? According to Kauffman, self-constructing agents attempt to expand, as rapidly as is sustainable, into the “adjacent possible” by acting on their surroundings to maximize the number of types of events that can happen next. Kauffman thinks an evolutionary strategy is robust if it contains alternative ways to do things in case the primary way is a dead end.
Investigations strikingly reveals how little progress naturalists seem to have made in bridging the gap between molecular systems and information-laden living organisms. In all observed naturally-occurring instances of increasing biochemical complexity, a mechanism with an overall entropy increase is the foundation. However, Kauffman’s proposals don’t yet offer a mechanism to explain how life’s complexity, as measured by its vast information content, came to be.
In the end, it seems that the alleged “new fourth law” is a glitzy repackaging of the old familiar laws of thermodynamics. Perhaps a more fitting term for Kauffman’s key concept might be the “adjacent improbable,” as applied to the origin-of-life question. Only those structures and events that are permitted by the laws of chemistry and physics will be viable, and some will be far more likely than others. Kauffman fails to show how to overcome daunting statistical improbabilities in naturalistic origin-of-life scenarios. He hints at a general biochemistry (or “astrobiology”) in which a generic catalytic toolkit exists, with each function performed by many possible chemical agents. However, the opposite is being observed in terrestrial biological systems: precise protein folding to achieve 3-D “lock-and-key” structures, a genetic code optimized for error recovery, and true molecular machinery.
As he develops his ideas of self-organization, Dr. Kauffman takes the reader on a grand tour of the cutting edge of modern science, often pursuing tangential details with little or no prologue. Even those with a good science background will find this book challenging in concept and delivery. A working knowledge of cell chemistry, mathematics, thermodynamics, and evolutionary theory is necessary to appreciate Investigations. Casual use of technical jargon such as “hyper-dimensional fitness landscapes,” “dimensional compactification,” and “Calabi-Yau space” may cause the reader’s eyes to glaze over. Fortunately, Kauffman incorporates an engaging style that brings the reader back for more.
Kauffman’s careful treatment of his scientific proposals, and his lucid presentation of admittedly difficult subject matter are thought provoking and educational. The scientifically literate FACTS for FAITH reader who is interested in the current research status of the naturalist paradigm will enjoy Investigations.
Dr. Tony N. Rogers is an associate professor of chemical engineering at Michigan Technological University (MTU). Prior to working at MTU, Dr. Rogers was a senior research engineer in the Center for Process Research at Research Triangle Institute. He specializes in the areas of thermophysical properties, chemical process design and simulation, and multi-criteria process optimization.