The Science of Evolution
Revolutionary Worker #1217, October 26, 2003, posted at rwor.org
In the United States, at the beginning of the 21st century, it is the case that many people still believe in gods or other supernatural powers. But it is also the case that many religious believers choose to hold on to religious faith while at the same time acknowledging that life has been evolving on this planet for millions and billions of years and that all the different species of life on earth, including humans, are related to each other through lines of common descent derived from different pre-existing ancestor species. Many also recognize and accept that the Bible was after all a book written down by very human authors, and that it is therefore bound to contain errors and viewpoints that reflect the outlook and the social agendas of these people who lived some 2,000 (or more) years ago. Some of the more blatant examples of condoned violence, brutality and social intolerance that can be found in the Bible (such as the rationalization of the patriarchal subjugation of women and children and slaves; favorable depictions of invading armies bashing babies' skulls and of entire cities laid to waste; calls for homosexuals to be put to death, etc.) are particularly disturbing to many modern believers. Many people just choose to ignore these parts of the religious scriptures. In fact, many of the more socially enlightened and progressive-minded religious people argue that, rather than taking the Bible as the literal "word of God," one should "pick and choose" only what may still be relevant in constructing a moral and ethical guidebook for how to live one's life in today's world.
Forward-looking religious people these days are often particularly interested in reconciling two things which they consider to be very important to human lives: a belief in a higher power which is thought to stand "above and outside" nature and humanity ( a "supernatural" god) and an acknowledgment and appreciation of modern science, including biological evolution. They want both . They feel they need both . They are adamant that religious belief should not be used to deny humanity the benefits provided by ever-expanding scientific knowledge and discovery.
But if science is continually pushing back the veils of ignorance, where can modern people still "find" god? Many people seeking to reconcile both religion and science in their lives tend to focus on things that are not yet fully understood or explained (in either nature or human society) and decide that these "unknowns" represent the particular province or sphere of influence of God. It's not just the fundamentalist Christians who like to say that "God works in mysterious ways." So, for instance, among the many religious people who do fully recognize and understand that life on this planet evolved, there are still quite a few who will say: "But maybe God at least got life started , in the very beginning? Maybe God created only those first living bacteria-like creatures and then just "allowed" evolution to take place in the ways we now know it did, including by Darwinian natural selection, and so on."
This idea that maybe a supernatural God first just breathed life into the very first living cells and then let the rest of life evolve and diversify "on its own" through the well-known mechanisms of Darwinian evolution is a very common point of view. And though we know all living species are made up of chemical elements that were common on this planet some 3.5 billion years ago, it is true that scientists have not been able to bring forth any complete and reproductive living cells simply by combining some of these chemical elements and attempting to recreate the right mix of environmental conditions which may have existed at the time. They have, however, already observed how some of these chemical elements will, under certain environmental conditions, tend to self-organize (all on their own) into some of the basic molecular "building blocks" of life (as was discussed in earlier installments of this series). Together, the developing fields of molecular and developmental evolutionary biology are making headway in better understanding these kinds of processes of molecular self-organization and the kind of steps which were likely involved in generating the first strands of replicating DNA molecules and the first reproductive cells.
Looking at this question from a somewhat different direction, a number of researchers have used computer models to show how even computer-generated self-reproducing "artificial life-forms" start evolving on their own (without any human being or other "intelligent designer" directing the process), how they often produce a bewildering diversity of new artificial life-forms and even generate some unexpected "solutions" to "design problems" that the human experimenters would not have anticipated. For instance, one such experiment (run by Karl Sims in the 1990s) involved a "population" of "varied individuals" (an assortment of simple "virtual blocks" made of two connected pieces) which were set by the computer program to "reproduce" (self-replicate). The experimenters did one other thing: they essentially programmed into the simulation the equivalent of a selective advantage for a given environment--for instance, programming into the computer that any of the virtual blocks that managed to "walk" would automatically have a reproductive advantage. It's important to understand the experimenters didn't design any of the blocks to "walk"--they simply programmed the computer to function like natural selection and give any blocks which happened to have evolved on their own any ability to "walk" a definite reproductive edge, meaning that those blocks got to contribute more descendants to the next generations than the blocks which hadn't evolved that new function. The experimenters didn't know ahead of time whether the self-replicating artificial life-forms would evolve such a function on their own or not. They just started the self-replicating program running and then just walked away and waited to see what would happen.
What happened next is that the self-reproducing "individuals" produced generation after generation of copies of themselves. But occasionally minor copying errors would pop up (the equivalent of mutations in real living creatures). And, lo and behold, purely by chance, some of these "mutations" happened to allow some of the blocks to move or "walk" (and different mutations actually produced all sorts of different ways blocks could "move"). Since in that particular artificial environment (the computer program) anything showing ability to walk enjoyed a reproductive advantage (producing more copies than those that didn't walk), it became apparent over time that the populations of descendant generations of blocks contained a greater and greater proportion of individuals with some kind of ability to "walk."
So, in this simulated computer environment, randomly occurring "mutations" (copying errors in the self-replicating programs), combined with some simulated changes in external environmental variables and constraints, ended up over time (many, many generations) bringing forth major new features of both form and function (remember: that particular simulated computer environment was such that any blocks with any ability to walk would reproduce better in that environment than blocks which hadn't evolved an ability to walk). And all of this without anyone having to intervene directly to make any of these specific evolutionary modifications or to "design" any of the newly emerging features! Artificial life simulations of virtual "block creatures" or simulations even of whole complex ecological communities containing different virtual organisms (as in the even more recent "Tierra" evolution simulations) demonstrate some basic principles of how evolutionary change can occur spontaneously and without being guided by any conscious designer, even in non-living systems. Such experiments, together with the many advances in molecular genetics and developmental biology which increasingly track the nuts and bolts of evolutionary changes in living organisms even at the sub- cellular level, are all contributing a great deal these days to our understanding of how the very first forms of life could well have emerged.
So, is our knowledge of the earliest origins of life complete? Of course not. But, for one thing, as many biologists have pointed out, even if we don't yet understand fully how the very first primitive forms of life emerged from the "chemical soup" of early earth (though we do have some beginning understanding of how this likely happened), there can be absolutely no doubt that life did evolve- -and has been evolving continually--ever since it first emerged. And we know a great deal about the mechanisms that are actually involved in that ongoing evolutionary process. So just because we still have a few holes in our understanding of how the very first living creatures (simple one-cell bacteria-like organisms) emerged out of the "chemical soup" some 3.5 billion years ago, doesn't mean we should throw up our hands and conclude that "god must have done it"! Something that is not yet known is not the same thing as something that can never be known. For instance, earlier humans didn't yet know about heart valves or brain cells or DNA, but the fact that humans didn't yet know about them didn't change the fact that these things existed; and at a later point, as human knowledge developed, science was able to reveal them.
Finally, in reflecting on the very earliest origins of life on this planet, the paleontologist Niles Eldredge aptly wrote a few years ago (in his very good book The Triumph of Evolution and the Failure of Creationism ):
"...complex organic molecules occur throughout the universe and many (such as amino acids, the building blocks of proteins) can be synthesized simply by passing a spark through a gaseous mixture of ammonia, methane, hydrogen, and water, as was first done by Stanley Miller in the 1950s using the ingredients thought to be the main atmospheric constituents of the primitive Earth. Creationists counter that such results are far removed from creating true life. Biologists, of course, agree, while maintaining that such experiments are both supportive and suggestive of the hypothesis that life did, indeed, arise from natural processes...in the brief history of biochemistry we have gone from laborious analysis of what proteins are (starting in the mid-19th century), through the cracking of the genetic code (in the mid-20th century), to the heady days of genetic cloning (at the end of the 20th century). That the origin of life, if posed as a biochemical problem, remains incompletely solved as of the year 2000 is not particularly surprising and certainly not compelling evidence that it never will be. But if we are to continue to teach our children that such problems are beyond the purview of science because `the Creator did it,' we certainly will lessen our chances of ever finding out. Yet that's exactly what creationists--including Philip Johnson and his colleagues--would have us all think."
The more science advances, the more human ideas about divine powers and supernatural realms get repeatedly undercut and revealed to have been nothing more than attempts made by humans to imagine what they could not yet understand. So to all those religious people who already acknowledge that there is overwhelming scientific evidence for evolution--who are already convinced that, once life had emerged on this planet, it proceeded from then on to evolve and diversify by purely natural evolutionary processes--I would suggest the following: by all means, let's never lose our sense of wonder at all we still do not know or fully understand (as well as our wonder at many things we now do understand); and let's definitely keep asking all sorts of hard questions, about everything; let's definitely work to unite all those (religious believers and non-believers) who want to try to do everything that is within human powers to positively improve the human condition; but let's also strive to be consistent in applying the methods of science for doing so-- consistently materialist methods , aimed at systematically uncovering the actual truth of things. Scientific methods of exploration and investigation have always helped us sort out what actually corresponds to material reality as it really is in nature and in society, from what doesn't actually correspond to reality as it really is. And it has always been the case that, as we uncover new truths about reality, we often have to discard old ideas and long-held beliefs, not because they are old but because a scientific approach and method reveals that they do not in fact correspond to the way things really are.
We need to keep following through on this "sorting out" process, ever more consciously and systematically. Even the earliest humans would have had to engage in primitive versions of this (a kind of science by trial and error) in order to survive and increasingly develop their ability to transform the world around them in keeping with their perceived requirements. The world around us is always changing, and human knowledge needs to continually develop and expand in relation to that.
Nothing in our human "tool-kit" is more important than a thoroughgoing materialist scientific method for uncovering the actual truth of things--a method consistently applied--a method which itself is the product of evolution, and revolution, in human development, including in our modes of thinking. To forward-looking religious believers and non-believers alike I say: why not make a pact to go wherever scientific methods for uncovering the truth of things may take us, even if what we uncover ends up posing some serious and uncomfortable challenges to some old assumptions and cherished traditions?