There is more in heaven and earth than can be dreamt of in any human philosophy. This is why science is not philosophy. Those who map the skies, observe the patterns of a school of fish or dissect molecular processes are well aware of this. We scientists wander dark and strange lands, and encounter startling landscapes and creatures beyond our wildest imaginations.
Only within the last few centuries have we come to realize that the great bowl of the dark night sky is filled with suns of a power and spectacle that we can’t even recreate in our mind’s eye. The ancient constellation of Orion contains bright blue Rigel and resplendent crimson Betelgeuse. In biology, microscopes have given our eyes access to a world previously unknown to us. The water bear, the tardigrade, is a beast of such profound strangeness that we perceive in its essence something deeply alien, as if it were from another realm altogether, and not just part of a world below our conventional acuity of perception.
And yet one hundred and fifty years ago Charles Darwin outlined his theory of evolution, which was predicated on the fact that all life on this planet shares a common descent: from fish to fowl, to the great beech tree and the lowliest pond scum. And, yes, humanity and the tardigrade as well.
Like many of Darwin’s insights, this has been proven by modern molecular biology in a way that he could not have anticipated. By and large, living beings on this planet carry within them strands of molecules which we call DNA, and those strands in their form, function and structure exhibit similarities and differences which perfectly recapitulate the tree of life that Darwin envisaged. His understanding of the world is written in our very genes.
And yet Darwin did not understand genes. That was the discovery of a Moravian monk named Gregor Mendel. Around the time Darwin was expounding the theory of evolution, Mendel was experimenting with the breeding of peas, and inferring from them that inheritance exhibited precise and systematic patterns of transmission from parent to offspring: his laws of segregation and independent assortment. Every generation, genetic variation reassembles itself in equal parts from each parent, as genetic variants mix and match in dizzying arrays, some resembling those of previous generations, and others startlingly new.
This was something Darwin, and many early evolutionary biologists, did not grasp. And that was very unfortunate, because Mendelian inheritance held the key to resolving a major problem for the theory of adaptation through natural selection: this process required heritable genetic variation and pre-Mendelian theories were either deeply wrong about the details, or they made predictions which would have meant that all of that variation would have disappeared within a few generations.
Mendelian genetics is one of those systems of understanding our world that is at once simple and elegant, and yet counterintuitive. The average human, using common sense philosophy, observes that the offspring of two parents are a mix of the characteristics of the parents. This is correct as far as it goes, but from this many assume that characteristics are being blended together. This is not what is occurring. Rather, configurations of genes lead to the characteristics. Genes are discrete units of heredity: they do not blend, but preserve a full range of potential variation from generation to generation. Variation does not disappear because the genes do not disappear. They rearrange.
Scientists are humans who live in the world, so sometimes novel and peculiar systems of analyzing facts and patterns can inform seemingly unrelated matters. Consider racial prejudice and discrimination.
I am a brown-skinned human being who lives in the United States of America. I know a bit about racial prejudice and discrimination from personal experience. My ancestors hail from the northeastern corner of the Indian subcontinent. My wife is of Northern European heritage. My children are mixed. This is just a small fragment of a broader dynamic the world over. Though the vast majority of people marry others who look and think like them, enough do not that one can imagine a future generation down the line, in which all lineages are interrelated.
The implication that many people make from this is that racism may disappear because racial distinctions of appearance will disappear. As people mix their genes, their physical characteristics will melt away into a uniform beige whole, as distinct human races become one human race.
And yet this common sense intuition is profoundly wrong. People of mixed racial heritage are not predictable mixes of their parents’ appearances, but express a range of looks. Additionally, as people of very different ancestry intermarry, combinations of physical characteristics unlikely to be found in most people today may become more common. Imagine someone with richly-curled blond hair, deep olive skin and almond-shaped, pale blue eyes set above high cheekbones. There is nothing genetically impossible about such a set of features as per Mendel’s law of independent assortment. They are simply rare today because of the happenstance of history and demography.
Looking forward into time, the science of genetics tells us that the full range of human physical expression will still exist, even if the fractions change, because the underlying genetic variation will persist. Some people will be such that we recognize them as white, or black or Asian. Many more will be unrecognizable combinations thereof. Science tells that the beige future will never arrive, because there are no genes for beigeness. Beige is simply one expression of genetic variation among many.
And curiously, ancient DNA looking backward in time has shown that the past was quite like what the future may be. Many peoples that we consider unique, distinct and primal are in fact genetically novel—the product of great mixings is tribes and nations long gone. Northern Europeans, the native peoples of the New World and South Asians are all the consequences of ancient mixings between profoundly different peoples.
Our intuitions about race are in many ways imperfectly related to the genetic realities from which they emerge. And those intuitions are embedded in the social histories of our cultures. In the United States one hundred years ago, segregation was a fact of law, and there were black Americans and white Americans. Today, it is not a fact of law—and there are black Americans and white Americans. There was no scientific difference between then and now. There has been a historical and moral process of change and development.
The dream of the beige future obviates the need to emphasize the moral and ethical aspect of the way we organize societies—in both its urgency and its difficulty. The dream is that science and the march of history will magically make the problems of racism disappear because racial distinction will disappear. The fact is that the genetics does not suggest any such thing. And the human tendency toward faction is likely deeply hardwired. Even if external physical appearance in complexion and mien was homogenized, other cues of dress and manner might become hooks for human groupishness.
Science and society are different. The dreams of science do not shape the character of society, but they inform the choices we make, and constrain the possible spaces of action. Society comes from nature, but in a deep pragmatic way it is not of it. Our human model of moral conscience can be guided by science, but ultimately it stands on its own two feet. The material stars above may inspire and inform us, but they do not guide us.
4 comments
Your Mendelian argument only works for small numbers of genetic loci. Just do the math. As the number of loci increases, the probability of a hybrid resembling one of the original genotypes approaches zero.
Suppose the original “pure” individuals differ at N loci and mating is random. Their descendants many generations hence will have an average of N/2 variants from each side, with a standard deviation of sqrt(N/4). So for N=100, we have a mean of 50 and a standard deviation of 5. This means you need a 6-sigma event (P80% similarity to one of the original “pure” individuals.
Extremely polygenic traits don’t behave like Mendelian traits. And *most* human traits are extremely polygenic (N>>100).
However skin color and most of the “racial” external markers are not extremely polygenic traits…
Razib Khan writes in a poetic way which is a pleasing way to learn or take in viewpoints.