By George Gantz
In Wonderful Life: The Burgess Shale and the Nature of History, biologist Stephen J. Gould theorized that evolution is essentially random and that if “the tape of life” for evolution were to be re-run, the end result would be entirely different:
The “pageant” of evolution [is] a staggeringly improbable series of events, sensible enough in retrospect and subject to rigorous explanation, but utterly unpredictable and quite unrepeatable. Wind back the tape of life to the early days of the Burgess Shale; let it play again from an identical starting point, and the chance becomes vanishingly small that anything like human intelligence would grace the replay. [1]
New research is increasingly challenging that view. Certain evolutionary outcomes have emerged more than once—and some appear to be inevitable. These are not exceptions to the laws of nature but are essential outcomes of mathematical and environmental constraints. Purpose seems to be deeply ingrained in the fabric of life, and recognizing this has implications for one’s personal beliefs.
Conventional Wisdom – Evolution Is Random
Many biologists have presumed that variation by mutation, a key feature of the evolutionary process, is random and that competitive selection pressure in the environment then picks the more successful options, allowing them to pass into the population in succeeding generations. Such a story based on improbability and unpredictability is an easy one to tell. As a consequence, many would agree with Stephen J. Gould that if evolution were to be re-run, it would end up with very different outcomes. Yet there are many findings that suggest this may not be the case. Here we will discuss two: Kleiber’s Law, which governs the relationship between size and metabolism for all animals, and the process of convergent evolution, which offers examples of how very different evolutionary lines come up with the same solution.
Kleiber’s Law – Limits to Size
In 1932, biologist Max Kleiber stated that as the size of an animal increases, its metabolic rate decreases. This indirect relationship sets a limit on the maximum size of terrestrial species, and it takes the form of the exponent for a “power law” (referred to as Kleiber’s Law), which is a non-linear mathematical formula commonly found in complexity theory.[2] Initially, the measured result for this relationship was an exponent of 2/3: the surface area of an object increases by roughly the square of its radius, while the volume (or mass) of an object increases by roughly the cube of its radius. Greater surface area helps metabolism go faster, while greater mass places demands on metabolism and therefore slows it down. This seems to make sense, given that metabolism sustains the mass of an animal, while internal heat is dissipated through the skin.
More measurements were made subsequent to these findings, and they suggested that the relationship of size to metabolism is more accurately expressed with an exponent of 3/4. This value was a mystery until 1997, when researchers realized that the means for distributing nutrients to all of the tissues is actually the limiting factor on metabolism for a larger animal. The circulatory system consists of the heart and a system of linear vessels, and these vessels have to reach the entire three-dimensional space within the body. Nature has devised a remarkably efficient way to do that—a branching fractal network that circulates blood from the heart to the arteries to the capillaries and then to the veins and back to the heart. Drawing on the complicated mathematics of fractals and partial dimensionality in relation to the circulatory system and its operations, the researchers’ calculations revealed the validity of this new exponent.
Kleiber’s Law highlights important constraints on how life can evolve. The evolutionary process appears to be random, but mathematics drives the process along specific paths. Nature’s solution to the management of nutrient circulatory systems in living systems is one of many common denominators that structure the evolution of life. So what is demonstrated in the unfolding of evolution is something much more subtle than its seeming randomness; it is a problem-solving process whose solutions to those things that challenge the persistence of life are inevitable outcomes of underlying mathematical laws. No matter how many times the evolutionary “tape of life” was re-run, the results of these laws would be the same.
Convergent Evolution – The Same Solution Over and Over Again
Convergent evolution is the process by which similar features appear to have evolved independently. Originally, biologists assumed that any particular function or feature, such as eyes or fins, only evolved once through mutation and natural selection and that the successful adaptation was passed on to succeeding species that evolved from the first. For example, since birds and bats both had wings, the expectation was that there would be a common evolutionary ancestor with wings. This, however, has proved not to be the case. While bat wings and bird wings have an identical function—flight—they are quite different in their structure and origin. Both evolutionary lines came up independently but with a functionally identical solution. Across the evolutionary spectrum, there are now hundreds of examples identified where similar features or functions evolved independently in species with different lineages and sometimes in different time periods.
If the random process of evolution repeatedly finds similar solutions to similar environmental challenges that confront these different species, how random can the evolutionary process really be? The fact that the same physiological feature can evolve more than once may not seem to be a big surprise, but it calls into question the assumption that evolution is random. If the “tape of life” were to be re-run, these same solutions would appear again. Perhaps, in time, science will find that sentient bipedal humanoids were an inevitable stage in evolutionary development.
The idea that the apparently uncertain process of evolution leads to an inevitable outcome is a relatively new development, but the seeds of this idea have been around for a long time. In 1972, a Swedenborgian scholar described the idea of “evolution by limitation” in this way:
In this theory the first natural created thing, spoken of as the natural sun, has all life forms in it. Organization of this matter is not an up-building from one lower form to another, but rather a drawing out of more specialized forms. Limitations being imposed upon this first natural form specialize its uses and so make it both more and less perfect. More perfect as to use, less perfect as to the potential expression of life. With the vegetable kingdom we found a limitation of this first created stuff in such a way that it could never be animal or human, although the original created stuff had that potential. So also with each generation of animals the original stuff was more and more particularized, that is limited, making that animal less and less able to become a man. . . . This was not an up-building process, but a limiting one, although there is the definite appearance of up-building due to specialization.[3]
Evolution and Spirituality Are Not at Odds
The initial reactions to Darwin’s theory of evolution were mixed, and a number of scientists were strongly opposed to his ideas. Surprisingly, many of the early proponents of Darwinian evolution were religious reformers (including Swedenborgians), who found Darwinian evolution to be a compelling demonstration of divine purpose.
In the century and a half since, however, a quite different mythology has taken hold: evolution often seems to be cited as a litmus test for scientific loyalty, while certain religious adherents maintain with equal ferocity that the theory of evolution is anathema. We have all seen books, articles, or bumper stickers that ridicule religious believers and trumpet the supremacy of empirical science as the only truth. On the other hand, in some communities and countries, religious fundamentalists have sought to undermine or even reject basic science education. Neither of these positions is helpful nor useful to our society.
The fact is that many scholars of biology are quite firm in their spiritual perspective on the evolving natural universe.[4] At the same time, many religious leaders, including Pope Francis and the Dalai Lama, are committed to scientific principles and findings, including evolutionary theory. This just goes to show that the prevailing mythology that evolution and religion are in conflict with each other is completely unfounded. Many top minds believe that evolution and a spiritual perspective on the formation of life are complementary positions, both of which contribute to increased understanding and appreciation for the complexity and beauty of creation.
The latest findings in evolutionary theory suggest a purposeful process. This is a useful perspective for opening dialog across the fields of science and spirituality toward a more integrated philosophy of what creation and life is and where it might be going.
George Gantz is a writer and philosopher and directs the Swedenborg Center Concord (SCC), a non-denominational educational project supported by the New Church of Concord, Massachusetts, that seeks to integrate the knowledge of science with the wisdom of religion.
[1] Stephen J. Gould, Wonderful Life: The Burgess Shale and the Nature of History (New York: Norton, 1989), 14.
[2] For more details on complexity theory, check out my article entitled “How Can There Be Order in Randomness?”
[3] Alfred Acton II, “Evolution,” The New Philosophy (1972): 151–165, 238.
[4] These scholars include Denis Alexander, author of The Language of Genetics (2011) and Creation and Evolution: Do We Have to Choose? (2008), and Francis S. Collins, author of The Language of God (2007) and director of the National Institutes of Health.