The Rhythm of the Cosmos

Related Story: The Wright Center and Eric Chaisson's Evolutionary Path

Every once in a long while, a window of opportunity opens for scholars to integrate their work into a larger, coherent whole. Perhaps once in a generation, or even only once in a century, the academic climate ripens to allow a synthesis of powerful ideas and abundant data that have been accumulating for decades. Those who provide the regular stream of information content are the specialists--hard-working researchers who toil on a daily basis to advance knowledge, often incrementally. Those who occasionally champion the large-scale integration are the interdisciplinarians--the mavericks of academia bold enough to propose whole new worldviews.
   After 50 years of government-sponsored science--the legacy of Tufts' graduate Vannevar Bush, A13--when the focus was on intense, even myopic, specialization during the second half of the 20th century, universities are now beginning to change, albeit slowly and perhaps only briefly. Interdisciplinarity is in; researchers are routinely crossing departmental boundaries. Specialization remains important--and is still funded--but a search for the "larger scheme of things" is receiving tolerance, if not honor. No one knows how long this new-found attitude will last among the community of educated men and women, but it seems clear that we are now entering a new age of synthesis.
   Cosmic evolution is one such interdiscipline--a unifying subject spanning the entire spectrum of the natural sciences. It is an attempt to identify common denominators and underlying laws among all structured things seen around us in Nature--the land, sea and air, the stars in the nighttime sky, life itself.
   Can we create a modern worldview that integrates all of the sciences into a unified whole? Is there some process or mechanism at work in the Universe that guides the emergence and growth of all ordered systems? Where did all the order come from anyway? Of course, some would say the answers are obvious: God. But natural scientists have a calling to seek to explain Nature, in all its wondrous manifestations, by using only reasoned logic and scientific principles. Tempered skepticism and experimental evidence comprise our central dogma.
   Simply stated, cosmic evolution is the study of change. More technically, it is the study of the many varied generative and developmental changes among all radiation, matter and life throughout the history of the Cosmos. If there is one aspect of the Universe that seems ubiquitous--for all things in all spaces at all times--it is change. The ancient Greek Heraclitus, a noted thinker of some 25 centuries ago, had it correct when he stated, "There is nothing permanent except change." His was an innate idea--a hunch--but what a powerful idea it was. For no matter how we examine Nature today, we see change, some of it subtle, some dramatic. Stars change, climates change, plants and animals change, civilizations themselves change. The whole Universe is awash in change, and it is that universal change that we call "cosmic evolution."
   From galaxies to snowflakes, from stars and planets to life itself, scientists are now weaving a neoplatonic pattern, penetrating the fabric of all the natural sciences--a sweepingly inclusive synthesis of order and structure among every known class of object in our richly endowed Universe. Neither new science nor appeals to nonscience are needed to understand the impressive hierarchy of the cosmic-evolutionary story, from quark to quasar, from microbe to mind.

The Cosmic-Evolutionary Scenario
   An accompanying figure on this page shows the archetypal symbol of the cosmic-evolutionary scenario--the "arrow of time." This intellectual road map stretches from the origin of the Universe to the present, from big bang to humankind. We astrophysicists debate the exact age of the Universe all the time, battling back and forth whether it's 8 or 10, or 15 or 18 billion years; most of us, as this figure implies, currently take 12 billion as the best estimate.
   Regardless, what's remarkable is not only that we can pin down reasonably well the ages of the Cosmos, the Milky Way, our Sun, the Earth and life, but also that these ordered structures fall along a temporal line that accords well with their degree of complexity. A well-ordered sequence of known systems--from stars to planets to life to intelligence--maps along the arrow of time, revealing simplicity changing into complexity, chaos into order, inorganic into organic. There is a story here, a historical narrative. And it's a story about ourselves--our origins.
   This is post-Renaissance thinking, without the strict, mechanistic determinism of Newton, Laplace et al. Cosmic evolution embraces a more materialistic, synoptic posture, wherein no obvious design or purpose is discernible scientifically; nothing seems pre-ordained, nor is anything clearly predictable. Chance mixes with necessity, reductionism with holism, physics with biology. All ordered structures arise naturally, indeed with increasing complexity over the course of time, owing largely to the expansion of the Universe and the thermodynamic conditions that change with it.
   Cosmic evolution traces a thread of change linking the evolution of primal energy into elementary particles, the evolution of those particles into atoms, in turn of those atoms into galaxies and stars, and of stars into heavy elements, the evolution of those elements into the molecular building blocks of life, of those molecules into life itself and then intelligence, and of intelligent life into the cultured and technological civilization that we now share. Despite the compartmentalization of academic science, evolution--broadly considered--knows no disciplinary boundaries.
   These are the changes that have produced, successively and successfully, our Galaxy, our Sun, our Earth and ourselves. The result is a grand evolutionary synthesis bridging a wide variety of scientific specialties--physics, astronomy, geology, chemistry, biology and anthropology, among others--a genuine natural history of epic proportions extending from the very beginning of time to the here and now.

Thermodynamics in an Expanding Universe
   Whether galaxy, gene or art, patterns in physical, biological and cultural systems are manifest expressions of order and complexity, and increasingly so over the course of time. For all such systems, energy is key. Energy is needed to create and maintain physical and biological structures (such as fusing stars or functioning biomolecules), and it is also needed to build and restore cultural artifacts (whether towering churches or elegant paintings). The flow of energy, as dictated by non-equilibrium thermodynamics, does seem to provide a powerful way to appreciate the growth of order, form and structure everywhere.
   Note that we are not talking about simple, everyday equilibrium thermodynamics learned in school or practiced by engineers. In closed, equilibrium systems, structures tend to break down; this is the famous law of entropy, or disorder. Unattended households grow more messy; lawns become unkempt, kitchens greasy, roofs leaky. Even human beings who fail to eat will gradually become less ordered and die. All things, when left alone, eventually degenerate into chaotic, randomized and unordered states.
   By contrast, in cosmic evolution, we emphasize open systems and non-equilibrium states. And that's where the energy flows come into play. About 100,000 years after the big bang, the previously equilibrated Universe suffered a symmetry break, owing solely to cosmic expansion, inevitably creating global conditions that departed from equilibrium. In this way, environments naturally arose suitable for the flow of energy, and eventually for the emergence of organized structures. The resulting islands of increasing order--namely, galaxies, stars, planets and life--are more than balanced by great seas of increasing disorder elsewhere in the environments beyond. All accords with the second law of thermodynamics--perhaps the most cherished law in all of physics. By considering both systems per se and their surrounding environments, we can prove that both structure and entropy (which, as order and disorder, are seemingly at odds with each another) can increase together--the former locally and the latter globally.
   Key questions flood the mind: What caused pockets of localized order to arise, thus fashioning galaxies, stars, planets and life? How has complexity emerged, and then increased, as systems experienced, in turn, physical evolution, then biological evolution, and, finally, cultural evolution? Have technological humans now become the agents of change, able to tinker with both matter and energy, including genes and environments, more than these factors currently affect us? How did the neural network within human brains acquire the sophistication needed to fashion societies, weapons, cathedrals, philosophies and scenarios of cosmic evolution? In short, what caused us to become sentient enough to contemplate our complex selves?

The Rise of Complexity
   Complexity itself is a slippery term. Few people agree on its definition, let alone how it might be quantified. Even among biologists, most of whom concur that complexity has generally risen throughout the history of life on Earth, the word "complexity" conjures up different metrics, almost all of them qualitative. In my work, I wish to push the envelope beyond mere words, indeed beyond biology. "The book of Nature is written in the language of mathematics," said Galileo, one of my intellectual heroes. Some see such an attitude as reductionistic--an attempt to reduce all understanding to physics--but I disagree. In cosmic evolution, like life itself, nothing is black or white, governed by chance or necessity; rather, it resembles shades of gray throughout, likely mixing specialization with synthesis, reductionism with holism--a concept only now emerging in scientific circles, especially in non-equilibrium complexity science.
   Making a long argument a good deal shorter, I return to the physically intuitive concept of energy--admittedly my physicist's bias, yet as universal a currency as anything known in science. But not just energy; rather, a term called energy rate density--the amount of energy flowing through open systems per unit mass or volume. In that way, we can meaningfully judge, or normalize, all ordered structures "on the same, level page," comparing their use of energy regardless of their size and scale. And when that is done, we find that miniscule amoebas have much higher energy flow densities than vastly larger galaxies; petite human brains much larger values than huge redwood trees.
   As might be expected for cosmic evolution--a unifying proposal incorporating physical, biological and cultural evolution--a sequential trend correlates well with the age of a given type of system. The final figure (previous page) shows how all biological systems have flows of energy density to and from their surrounding environments far more than for any physical system. And, in turn, cultural systems, such as cities, economies and all of civilization utilize still much greater energy flows--an analysis that often dismays sociologists and economists who find it amusing, at best, to see their social studies analyzed thermodynamically. At least Heraclitus would have been pleased, even if puzzled by the modern details, given another of his succinct maxims: "All flows."
   This is not to say, by any means, that galaxies per se evolved into stars, or stars into planets, or planets into life. Rather, our analysis suggests that galaxies gave rise to environments suited to the birth of stars, that some stars spawned environments conducive to the formation of planets, and that an untold number of planets fostered environments ripe for the origin of life. This is Nature writ large.

Evolution, Broadly Considered
   The word "evolution" need not be the exclusive purview of biologists. In fact, Darwin never did use that word as a noun--and only once as a verb, in the very last sentence of his 1859 classic, On the Origin of Species. Biological evolution is merely a subset, albeit an important one, of a much grander evolutionary scheme stretching across all of space and time. For the more we examine Nature, the more everything seems related to everything else. Indeed, the concept of evolution, broadly considered, has become a powerful unifying factor in all of science, underlying the rise of complexity everywhere.
   Selection, adaptation and reproduction--terms that biologists often take as their sole province--might well apply to physical and cultural systems beyond biology. The word "selection" itself is a bit of a misnomer, as there is no known agent or active force that deliberately selects. I prefer the term "non-random elimination," suggested to me several years ago by the foremost living evolutionist, Ernst Mayr, implying that selection is less a force than a passive editor or pruning device to weed out the unfit. Accordingly, selection can be broadly taken to mean preferential interaction of any object with its environment--a more liberal interpretation that also helps widen our view of evolution.
   As for "replication," one hears the word increasingly used in astronomical circles. Given recent studies in sequential star formation among interstellar clouds--wherein the death of some stars actively triggers the birth of others and repeatedly so--it is not inconceivable that a kind of replication is at work in the dark recesses of the Cosmos. Said leading astrophysicist Patrick Thaddeus recently, "If you consider long enough intervals of time, stars are as replicative as any bugs in a petri dish."
   There is no question that biological evolution (neo-Darwinism) is much richer than any kind of physical evolution among inanimate objects. No one is saying otherwise. There is real added value to the genetic information stored in living systems, and that's partly--along with enhanced energy flows noted above--what makes us more complex. Likewise, cultural evolution (mostly Lamarckism) is richer still, capable of producing cities, states and empires that are so socially complex as to play havoc with our very well-being as a civilization.
   These are heady issues, vital issues, indeed, deep intellectual issues that ought to be raised more often in university settings. Humankind is now moving toward a time, possibly as soon as within a generation or two, when we shall no longer be able to expect Nature spontaneously to provide for us the environmental conditions needed for survival. Rather, society itself will have to create artificially the very conditions of our own ecological existence. From the two, society and the biosphere, will likely emerge a socially controlled bioculture. Here the components become ideas, artifacts, technology and humans, among other living organisms and machines on Earth--the epitome (thus far) of complexity in Nature.
   Perhaps Vannevar Bush's wartime colleague, Harvard president James Byrant Conant, was right when he quipped that "education is what's left after all you've learned has been forgotten." I'd like to think that the grand theme and historical narrative of cosmic evolution--an interdisciplinary survey of all the sciences, indeed a powerful worldview for the 21st century--are among those bits of education that will indeed be remembered long after all the details of conventional course work are forgotten.
    I'd also like to think that the scenario of cosmic evolution grants us unparalleled "big thinking," from which may well emerge the global ethics and planetary citizenship likely needed if our species is to survive to play a role in that same cosmic-evolutionary scenario.

Eric Chaisson is director of the Wright Center for Science Education and professor of physics and of education.

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