SCOTT D. SAMPSON is a paleontologist, chief curator of the Utah Museum of Natural History, and an associate professor in the Department of Geology and Geophysics at the University of Utah.
The truly dangerous ideas in science tend to be those that threaten the collective ego of humanity and knock us farther away from a central position within nature. The Copernican Revolution abruptly dislodged humans from the center of the universe. The Darwinian Revolution yanked Homo sapiens from the pinnacle of life. Today another menacing revolution sits at the horizon of knowledge, patiently awaiting broad realization by the same egotistical species.
The dangerous idea is this: The purpose of life is to disperse energy.
Many of us are at least somewhat familiar with the second law of thermodynamics, the unwavering propensity of energy to disperse and, in doing so, transition from high-quality to low-quality forms. More generally, as stated by ecologist Eric Schneider, “nature abhors a gradient,” where a gradient is simply a difference over a distance—for example, in temperature or pressure. Open physical systems—including those of the atmosphere, hydrosphere, and geosphere—all embody this law, being driven by the dispersal of energy, particularly the flow of heat, as they continually attempt to achieve equilibrium. Phenomena as diverse as lithospheric plate motions, the northward flow of the Gulf Stream, and deadly hurricanes are all examples of second-law manifestations.
There is growing evidence that life, the biosphere, is no different. It has often been said that life’s complexity contravenes the second law, indicating the work either of a deity or some unknown natural process, depending on one’s bias. Yet the evolution of life and the dynamics of ecosystems obey the second law’s mandate, functioning in large part to dissipate energy. They do so not by burning brightly and disappearing, like a fire torching a forest, but through stable metabolic cycles that store chemical energy and continuously reduce the solar gradient. Photosynthetic plants, bacteria, and algae capture energy from the sun and form the core of all food webs. Other kinds of life-forms consume these “producers,” making the most of the available energy pool.
In a very real sense, then, virtually all organisms, including humans, are sunlight transmogrified, temporary waypoints in the flow of energy. Viewed from a thermodynamic perspective, ecological succession—that is, changes in the species structure of an ecological community over time—is a process that maximizes the capture and degradation of energy. Similarly, the tendency for life to become more complex over the past 3.5 billion years—as indicated by increasing complexity in anatomical forms, metabolic pathways, and trophic interactions, as well as increasing biomass and biodiversity—is not due simply to natural selection, as most evolutionists still argue, but also to nature’s efforts to grab more and more of the sun’s flow. The slow burn that characterizes life enables ecological systems to persist over deep time, changing in response to external and internal perturbations.
Ecology has been summarized by the pithy statement: “Energy flows, matter cycles.” Yet this maxim applies equally to complex systems in the nonliving world; indeed, it unites the biosphere with the physical realm. Complex, cycling, swirling systems of matter have a strong tendency to emerge in the face of energy gradients. This recurrent phenomenon may even have been the driving force behind life’s origins.
This radical idea is not new, and certainly not mine. Erwin Schrödinger was one of the first to highlight the modern energetic view, as part of his famous “What Is Life?” lectures in Dublin in 1943. More recently, Jeffrey Wicken, Harold Morowitz, Eric Schneider, and others have taken these concepts considerably further, buoyed by results from a range of studies, particularly within ecology. Schneider and Dorion Sagan provide an excellent summary of this hypothesis in their 2005 book, Into the Cool.
The concept of life as energy flow is profound. Just as Darwin fundamentally connected humans to the nonhuman world, a thermodynamic perspective connects life inextricably to the nonliving world. This dangerous idea, once it has been broadly distributed and understood, is likely to provoke reaction from many sectors, including religion and science. The wondrous diversity and complexity of life through time, far from being the product of intelligent design, is a natural phenomenon intimately linked to energy flow within the physical realm.
Moreover, evolution is not driven by the machinations of selfish genes propagating themselves through the millennia. Rather, ecology and evolution together operate as a highly successful, extremely persistent means of reducing the gradient generated by our nearest star. In my view, evolutionary theory (the process, not the fact of life’s common ancestry!) and biology generally are headed for a major overhaul once investigators fully comprehend the notion that the complex systems of earth, air, water, and life are not only interconnected but interdependent, cycling matter in order to maintain the flow of energy.
Although this statement is reductionist and materialist in the sense that it accounts for a broad diversity of phenomena with a single physical process, it must be noted that the idea is entirely mute with regard to spiritual meaning. That is, the word “purpose,” as applied here, refers solely to naturalistic function—the workings of natural systems. Thus in no way does it exclude other, “higher” purposes. Nonetheless, the notion of life as an agent of energy flow is likely to have deep effects well outside the boundaries of science. In particular, broad understanding of life’s role in dispersing energy has great potential to help humans reconnect to nature at a pivotal moment in our species’ history.