Since the Scientific Revolution, the philosophy of science has been characterized by an almost exclusive reliance on logic, mathematics, and the laws of physics. But in recent years we have witnessed a laudable state of ferment in the field. This unrest seems mainly from the growing realization that any philosophy of science must do justice to the living world as well as to the physical one.It was my great good fortune to take high school biology with Bill "Mo" McGee. A trained geneticist, Mo had worked for a while with the US Forest Service, in a project to assist in the revival of various species of southern pines that faced, in the 1950s, something of an attack. The group with which he worked managed not only to save the trees, but get them to thrive. As my father said once while visiting our home in Virginia, "Mo would love it here. He knew everything about these southern pines."
Ernst Mayr, Towards a Philosophy of Biology, p.v.
Mo was also unafraid to bring up Charles Darwin. In fact, he was quite clear that it was impossible to understand biology without understanding what Darwin taught; it was impossible to understand the living world, medicine, even what we were learning in our labs when we dissected everything from a sheep's eye to two-foot long sharks (removing the eyes, the nasal bulbs, and the spinal cord from its cartilaginous sheath) without understanding what Darwin said about the development of life on earth. He did so simply, directly, without muss or fuss or even mentioning that there might be a controversy about the subject.
While I have always maintained an interest in what is loosely termed "naturalism" - a fascination with the study of various species of plants and animals as they live out their lives in the world - it wasn't as high on my list as other things; other than the occasional grumpy mumble whenever I read about some yahoos going after Darwin's theory of evolution, I didn't pay nearly enough attention as I did to other things. Fast forward from that dim lecture hall in 1980 to the book shop in the National Museum of Natural History at the Smithsonian in 1998. Lisa and I traveled to DC for a quiet, family Fourth of July. Moriah was days away from her first birthday, and despite typical heat and humidity, it was nice enough to stroll through the streets of the nation's capital, visit our favorite museums, and generally spend a pleasant day together. While in the gift shop after seeing the major sights, I was perusing the books shelves when one title practically smacked me in the face.
I had left CUA and the philosophy of science a year before; I faced the choice either of full-time graduate student work for many years, or full-time fatherhood, which really didn't seem like much of a choice. All the same, my still unformed thoughts on the subject swirled about, and the book was inviting me to take it home. The opening paragraph of the Preface, the epigraph above, was more than intriguing. It was a reminder of a point that had been made, over and over, by several faculty in the School of Philosophy: Darwin's theory of evolution by natural selection was not science. Mayr himself cites none other than Karl Popper writing in 1974 that the theory was a "metaphysical research program". Precisely because it, and the larger science within which it worked, was different from physics, the theory of natural selection was different in kind from theories in physics, astronomy, and even chemistry, most philosophers held it in a certain kind of contempt. Kuhn, whom one might have thought would have mentioned Darwin in a book explaining scientific revolutions, talks more about Benjamin Franklin - whose work in electricity altered the study of the field - than he does Charles Darwin, or Gregor Mendel, or even Watson and Crick. "Science", it seems, is physics and, as long as it pays homage to physics, chemistry.
I wrote yesterday that reading Stephen Jay Gould's Wonderful Life was like a huge bomb going off, forever altering how I understood matters of life and evolution and necessity versus contingency. Reading Mayr was similar; by reminding readers that biology was a science, just different in its assumptions, methods, and structure than physics or chemistry, he forced this reader to reconsider the whole question of "philosophy of science". Already familiar with the divide between what the Germans call the natural sciences and the human sciences, I realized that even in the natural sciences, there was a divide between those who understood themselves to be discussing "science" and other, lesser things.
Mayr argues in this series of essays that the reduction of "science" to physics is mirrored in these same philosophers, and many practitioners of the scientific enterprise, with a demand that biology reduce itself, at the very least, to biochemistry. Because chemistry itself faces the demand to reduce to physics, the through-line here should be clear enough: Biology, with its preference for qualitative research and description, its basic research program - natural selection - priding itself on its inability to predict specific events in the future but only describe the past, should surrender to the Truth that, at heart, we living things are little more than masses of particles in motion. If we can understand the chemistry and physics of living creatures, that should teach us all we need to know, as well as serve the usual, predictive, function of scientific theories that natural selection happily eschews. Like many who thought they might know a thing or two, reading Mayr was a lesson in the reality that, as that old song says, "Don't know much biology."
Part of the problem non-biologists have with biology is the reality that it encompasses a wide variety of sub-specialties that study specific questions that can only be understood within a larger framework. As the various levels of study - from biochemistry through histology to anatomy and physiology - each demonstrates a certain amount of integrity; at the same time, these lower-order specialties exist within a whole that cannot be reduced to these specific areas of study. This is best demonstrated by our flirtation with genetic reductionism. It is often argued that, should we find specific genetic sequences that can be linked to anything from alcoholism to cancer, we could intervene during gestation to prevent the development of what are considered these "faulty" sequences. The problem with this view is that DNA does not "determine" our life. Deoxyribosenucleic acid codes for the metabolizing of proteins. That's all it does. As specific proteins are metabolized, the resulting chemical reactions produce higher-order phenomena, the creation of cells with specific metabolic functions. These cells, in turn, become organized through chemical tracers used for communicating function, in tissues. This synthesis to ever higher, non-reducible structure and function results in the creation of a tree, a frog, or a person.
That there is a correlation between certain gene sequences and alcoholism is now well-known. This does not mean, however, that a person with that particular gene sequence is destined to be an alcoholic. Even should an individual with that particular gene sequence live within a context in which alcohol consumption is accepted and practiced, there is no cause-and-effect that links this particular genetic sequence to alcoholism. Many other factors, some biological while others are behavioral, come in to play. We cannot reduce our understanding of individuals to DNA. With the rare exception of certain physiognomic traits - hair and eye color, say - higher-order phenomena, including disease and behavioral and psychological dysfunction, cannot be understood from a study of genetics. It may well lead to certain paths for further research; DNA, however, is not destiny. We may look the way we do thanks to our genes. We are not, however, who we are, even in a biological sense, because of our DNA.
The matter is further complicated by the fact that biology deals not only with individuals. It also has to consider populations. Natural selection works both on the individual level, as genetic variation results in specific differences between individuals; it also works within the larger pool of genetic variation to produce, over time, either greater diversity that can lead, over time, to specific differentiation, the heart of evolution by natural selection, or should a population become isolated and genetic variation shrink, to extinction. We cannot understand evolution if we forget that it is constantly at work within populations, using the total pool of genetic variation within a population. Responding to ever changing environmental circumstances, evolution works to enhance those biochemical differences that result in individuals who are more likely to provide offspring, adding their distinctiveness to the larger population. Speciation occurs within populations, thanks to the large pool of available genetic information. It cannot be reduced to specific differences between individuals even within the same consanguineous, reproducing population.
Understanding that biology is different in kind from physics and chemistry, yet nonetheless has an integrity, method, and self-understanding no less sophisticated than either dealt, in essence, a huge blow to my thoughts regarding philosophy of science. How was it even possible to use those three words together when, in fact, what most people engaged in the pursuit were really attempting was a description of physics? Furthermore, the success and on-going practice of the various fields of the biological sciences, as well as the refinements of Darwin and Mendel and the success of this synthesis in guiding research mocked the insistence of those who insisted that biology, or the theory of natural selection, or medicine, are not sciences. They are, and folks studying in the field are quite happy with the designation. All those folks who nod in approval at Popper's comment about "metaphysical research program[s]" demonstrate more a kind of intellectual blindness than they do an acumen about biology that biologists themselves lack.