Science writer Michael Brooks lists “five discoveries taking science by surprise“.1 Number 5 is that “human beings are not special”. Think culture sets you apart from the beasts? Chimps, crows, and dolphins have it, too. Personality and morality? Elephants, rats and spiders are there with you. The ability to feel? Nah, even cockroaches do it.
But maybe things cultural and mental are too soft to build such momentous distinctions on? Well, maybe, but there’s no consolation in that. Brooks knows that “even the hard facts are letting us down”: we’re sharing over 99% of our genes with other species. The genetic difference is almost non-existing.
Now that has been the naturalist’s favorite knockdown argument for more years than I care to count. Whenever the continuity of Homo sapiens with other great apes needed assertion, the famous 99% (or 98.5% or 98%) figure was triumphantly presented, like a winning card that is slapped on the gambling table. The magic words “We share 99% of our genes with chimps” shut up interlocutors immediately, convincing them that no argument for human uniqueness could ever get off the ground. I, however, propose a different course of action. Instead of being dumbfounded, I suggest asking “So what?”
To see why this is an entirely appropriate response, one needs to examine what it is that makes the 99%-argument so immediately persuasive. Half of the answer is that as molecular biology emphasized for decades the power of genes to determine human nature, society’s view of personal and ethnic identity has changed to one giving increasing importance to genetic relatedness.2 Politically correct arguments about racial differences in IQ, for example, have often resorted to the alleged fact that races do not really exist since they do not have distinct genetic profiles. A similar argument for the brother- and sisterhood of all mankind asserts that almost all genetic variation among individuals is within and not between populations. «Genetic data show that, no matter how racial groups are defined, two people from the same racial group are about as different from each other as two people from any two different racial groups.»3,4 Questions of who people are, where they come from and where they belong, are now legitimately answered by the facts of genetics.
However, we have come to accord to genes the power to define our identities by virtue of one of biology’s more spectacular misconceptions. The idea that the genome carries instructions or even a program for building organisms has been enormously influential in- and outside of genetics. We take it for granted that genes form the core of our biological selves, and that they can do this because they carry within them the specifications for our bodies and maybe even minds. Only 30 years ago, this “information metaphor” was the main selling argument for the Human Genome Project (HGP). Once we’ve assembled the full “text” of our DNA, it was said, we will have unlocked the door to vast stores of knowledge about ourselves as individuals and as a species. Medical professionals will be able to read out a person’s health risks from their genetic sequence. Soon enough, the ability to eliminate the genetic causes of illness will revolutionize medicine. And so we paid the 3 billion dollars.
The belief in the instructive powers of genes is so deeply ingrained in our collective consciousness that hardly anyone knows that molecular biologists of the 1950s appropriated the term “information” without any decent bit of scrutiny. Storing and passing on information or instructions seemed to describe so perfectly well what DNA was doing that the need to examine the idea further simply did not arise. With similar nonchalance, the French introduced the notion of genes embodying developmental programs on nothing more than a glorious non-sequitur (literally; read it up here5).
When the information metaphor finally was examined properly (usually by philosophers of science, not scientists themselves), it was found wanting. In fact, it turned out that there is no evidence at all for the existence of the kind of information biologists ascribe to genes.6 As a result, there is no, and has never been any, reason to believe in the power of genes to uniquely bestow identity.
Partly for this reason, the argument for the phenotypic similarity of humans and chimps from their genetic similarity is a non-starter. Genes don’t deliver identity, so a 99% overlap doesn’t necessarily make two species soul mates. I have often wondered about how uncritically people swallow the 99%-argument, particularly in the face of an obvious reply: “Well, just look at the two species, how they live and what they look like. It sure seems like there’s a world of difference!”7 Although common sense cannot generally be trusted, in this case it captures something essential that the genetic argument ignores: the manifest large gap in mental and cultural endowment. This is not about insisting on some singular human feature that categorically sets us apart from our great ape relatives. It is merely pointing out that the cumulative effects of mind and culture have made Homo sapiens into something clearly different from other animals. Something special, unprecedented, freakishly new.
Even if the information metaphor were right and genes had special deterministic powers, should this evident inter-species gulf cast doubt on the 99%-argument. At least, one would have to conclude, if the 99% percent shared genes still leave the two kinds so different, it clearly hasn’t much effect. The fact that genetic relatedness has such a weight in an overall judgement of our various qualities relative to those of other species doesn’t exactly inspire trust in the logic of scientific naturalization. Quite frankly, it is nothing but a shallow bit of reductionism.
Then there’s the other half of the reason why the genetic argument is so convincing. The naturalization program that originated with the birth of modern science and received its major boost by Darwin has solidified into something of a dogma. Together with today’s robust materialism it has created a perception that it is the mandate of an enlightened naturalism to show the total continuity of humans and other Homininae and, by extension, the entire animal realm. But this is not a “discovery”, as the title of Brooks’ piece suggests. It is always a matter of subjective judgement whether to draw a categorical distinction between entities, even if aided by objective facts. Yes, there are lines of continuity with our primate cousins, most obviously the common ancestry through evolution. On the other hand, the differences in psyche, language and culture are striking. Nothing but the metaphysical trends of our time forces us to prioritize the genetic and evolutionary links.
History is marked by pendulum swings. Trends rising, taking over, and, after dominating for a while, being displaced by opposing ones that then go through the same cycle. The pendulum doesn’t swing back to the same place, rather, it moves forward as it swings, making the extreme points not so much direct opposites as eternal dichotomies that continue to surface in new guises.
There is a danger of confusing this pendulum of changing opinions with the truth. Oftentimes, when, during one half of the swing, we have come to see the shortcomings of the prevailing view, we start to push back hard, driving the pendulum in the other direction, and often we do not care that we leave much of what is true about the old view behind.
A favored shibboleth of naturalist history is how man’s hubris in thinking himself at the pinnacle of creation received its first big blow by Darwin. The pendulum started swinging back, and it is still swinging today. The German primatologist Volker Sommer asserted in an interview: “In the past decades the myth of man as the only cultural being has been shattered.”8 But I think such insistence is moot. As long as the naturalist doesn’t have a stronger case, it is not so much an argument as it is a battle cry. “Come on, let’s prove human arrogance wrong!”
I have already explained how the supposed “knockdown” argument from genetic similarity is, if anything, knocking down only the naturalist. Other arguments by Brooks and Sommer don’t look much better. Brooks says
One thing does set us apart: our linguistic abilities. These, however, are a quirk of evolution. Although nothing in the animal kingdom is using what we think of as language, gestures used by bonobos and orangutans come close. The fact that we have slightly different anatomical arrangements that allow us to speak is hardly a marker of a fundamental difference.1
What is that but hand-waving? What does it matter for human uniqueness whether language is a quirk or not? What is a quirk, anyway? Gestures by bonobos and orangutans come close? And it is plain that they come so close as to obviously invalidate any categorical demarcation between us and them?
Sommer talks about how “vain homocentrics” will keep denying the cultural commonalities between humans and other great apes and keep raising the bar for apes to enter the circle of man. In the end, he says, it will turn out that “man is the only creature that knows the formula for Coca Cola”.8
I know, Sommer isn’t entirely serious, and probably he’s exaggerating for the good cause. After all, he’s part of a movement to give moral rights to non-human great apes, securing better living conditions for these marvellous creatures. By moving us closer to them, his appeal gains the power of sympathy by similarity. “Protect them, they are like us.” Whatever the merit of such a strategy9, it doesn’t change the facts. In particular, it doesn’t close the still very apparent gap between ourselves and our hominin friends.
The naturalist might be tempted to object that, surely, this gap will eventually be naturalized away. Whatever it is that still seems to categorically separate ours and their species must and will be shown to be merely a difference in quantity, not quality. Naturalization is the only way to go.
The first reply to this is that categorical demarcations are subjective and a quantitative difference can sometimes surely be big enough to be felt as a qualitative leap. Day and night, categories, yet separated by a continuous gradient of brightness.
More importantly, the objection might still pack some clout if modern tendencies of naturalization and materialism had been unmitigated successes. “Every phenomenon science has come across so far has yielded to reduction to material/natural causes.” Many scientists I’ve met believe this, but it is not true. The most glaring counterexample is phenomenal consciousness (what is sometimes called “qualia”), which has not only stoutly resisted all attempts at physical explanation, but increasingly reveals itself as a phenomenon for which a recognizably physical explanation is not even imaginable.
This matters also for the case of humans vs apes. The richness of consciousness, including self-consciousness, humans have achieved is another of our unique features. To the extent consciousness turns out to be irreducible to physics we have to consider the possibility of an inter-species gap that cannot be naturalized away. Maybe with the addition of levels of consciousness such as ours a new ontological quality has been injected into the evolutionary process.
Let me be clear: it hasn’t been shown that everything that separates us from the apes must be physical or natural in the sense in which these descriptors are currently used. Despite appearances to the contrary, science cannot rule out immaterial consciousnesses or other intangible phenomena that might be uniquely human. In the case of consciousness, the evidence points, if anything, to the conclusion that we deal with an entity that cannot be captured by a physicalist explanation.
So, before the facts are in, it is by no means obvious that all-out naturalization is the way to go. It may be, as remarked earlier, that differences between Homo and his nearest relatives are gradual, but their accumulated weight justifies a qualitative separation. It may also be that somewhere along the path from the hominids’ common ancestor to our species, ontological discontinuity struck and rendered us categorically different from the other great apes. Or it may be that the difference is really only one of degree, nothing worth having deslusions of grandeur about.
In any case, it is an irony for science that the most deeply-held beliefs of its practitioners often are not empirical facts but fashionable metaphysical commitments. Dualism is so obviously false. Theism is so obviously misguided. Bla bla and so on. I suspect some similar ideological trend is at work when naturalists today vigorously insist that we’re nothing but an unspecial branch on the phylogenetic tree of apes. The fact that specious arguments like the 99% genetic overlap are so popular and persuasive, yet remain mostly unquestioned, would certainly support such a view.
1Brooks M (2014) Five insights challenging science’s unshakable ‘truths’. The Observer, 06/29/2014
2Nelkin D & Linde MS (2007) The DNA mystique. The gene as a cultural icon. 2nd ed. Ann Arbor: The University of Michigan Press.
4This is optimistic. With an increasing number of loci examined, individuals from different populations, including “races”, can be increasingly distinguished genetically. See Witherspoon DJ, Wooding S, Rogers AR, Marchani EE, Watkins WS, Batzer MA, Jorde LB (2007) Genetic Similarities Within and Between Human Populations. Genetics 176:351-359.
5«The discovery of regulator and operator genes, and of repressive regulation of the activity of structural genes, reveals that the genome contains not only a series of blue-prints, but a co-ordinated program of protein synthesis and the means of controlling its execution.» – Last sentence in Jacob F & Monod J (1961) Genetic regulatory mechanisms in the synthesis of proteins. J Mol Biol 3, 318–356.
6Gamma A (2013) The Role of Genetic Information in Personalized Medicine. Perspectives in Biology and Medicine 56, 485–512.
7Even a remark such as “Hey, we dress, they don’t” is at least as insighful regarding our species’ similarity with great apes as is the percentage of genetic overlap.
8«In den vergangenen Jahrzehnten ist der Mythos vom Menschen als einzigem Kulturwesen jedenfalls zerbrochen.» – Willmann U. “Ich bin ein Affenmensch“. Interview mit Volker Sommer. DIE ZEIT Nr. 52, 12/20/2000. Accessed 07/20/2014.
9It can be dangerous. If you base somebody’s right to live and prosper on scientific facts about their similarity to you, what will you do if it turns out one day that the facts were wrong? Will you conclude you now have to deny them that right?