In Terry Pratchett's Discworld series, the universe runs on narrativium - the element that ensures that things follow the demands of the story. It's narrativium that mandates that the little old lady in the woods is a witch, narrativium that demands that a third son, attempting a task that killed two older brothers, succeed, and narrativium that ensures that the million-to-one chance succeeds 99% of the time. In The Science of Discworld 2, Pratchett and co-authors Ian Stewart and Jack Cohen point out that storytelling is a key characteristic of humans, and that it has been essential to our evolution. Instead of Homo sapiens, the Wise Man, they claim, we should be Pan narrans - the storytelling ape. With that statement, the three find themselves falling victim to a story that we've been telling ourselves a fair bit over the past few centuries - the "nothing special here, just another ape" story. It's a compelling story, but one that is what Pratchet, Stewart, and Cohen called (in an earlier book) a "lie-to-children."
The suggestion that we are the third species of chimp is one that is made mostly for political or philosophical reasons. It is made to reinforce the story that science has been telling us, and that we have been telling each other, since the start of the scientific revolution - humans are nothing special. We are not at the center of the solar system, the solar system is not at the center of the galaxy, there are lots of galaxies in the universe. Time did not begin when we did, and there was life before us. We are not separate from the rest of creation. We are related to everything else that is alive on this planet, and if you go back up the family tree for long enough you will almost certainly find that at least one of your ancestors was a monkey's uncle.
Narrativium, it would seem, demands that we be the Third Chimpanzee. But even if the chimps would take us back, we don't get to take the easy way out.
We are not chimpanzees. We, unlike the chimpanzees, have the capacity to understand our effects on other living things. We, unlike the chimpanzees, can see the possible effects of our actions. We, unlike the chimpanzees, can see, can understand, and can -if we so choose- act to mitigate the harm that we have done and are doing to the planet. We, unlike the chimpanzees, can choose to do our human best to ensure that our children's children's children get the chance to live on a planet that is as safe and pleasant as the one our grandparents borrowed from us.
Calling ourselves "The Third Chimpanzee" fits in neatly with the narrative that has been used to describe our increasing understanding of our place in the universe, but it really isn't a fair description - either for us or for the chimps. It minimizes the things that set us off from other animals. It could be argued that this is a good thing, since it reminds us of our connection to the rest of life. Really, though, it's a cop-out. By labeling ourselves as another animal, we dodge the awesome responsibility that our human traits impose upon us. We have evolved the ability to understand (if only imperfectly) our world. We have evolved the ability to understand (if only imperfectly) the effects of our actions. We have evolved the ability to create, to debate, and to live by (if only imperfectly) concepts like fairness and justice. To the best of our knowledge, no other animal on the planet has those abilities. We, alone, have evolved them, and we, alone, have the responsibilities that come with them. The other apes do not share that responsibility, and they do not share the blame for neglecting it.
In truth, we really aren't what Jared Diamond called "The Third Chimpanzee." We may not be the "Wise Man" yet, but that description might just be within our reach. If it's not, we're all screwed. In our ability to understand that, if nothing else, we find the biggest and most important difference.
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You are engaging in wishful thinking.
As far as we know, there is no difference between ourselves and the other great apes that is not a question of degree rather than kind. Introspection, fairness (I once knew a dog that had a well developed sense of what was fair) and the ability to anticipate consequences (ever see a puppy misbehave - and then clearly anticipate consequences for the mis-behavior?)
We are indeed 'just another animal'. It is those who deny that that whom are engaged in political or philosophical pandering to the human desire for exceptionalism.
That in no way relieves us of our responsibility for our actions. That responsibility is not built on exceptionalism but on simple self-interest: If we want a nice planet to live on long term, then as the currently dominant species it is incumbent on us not to trash it.
Even when we're aware of the power of a narrative hook, it's really, really hard to resist one that fits our view of the world. It satisfies my view to say that we are biologically the Third Chimpanzee. The crux of the matter is your assertion, Mike, that "It minimizes the things that set us off from other animals." I don't think so. The things that set us apart are just as important as you say they are. But they don't negate our biological and evolutionary status.
In this I think I'm disagreeing with Mr. Franz: It is indeed our differences that make us responsible. The cyanobacteria that oxygenated the atmosphere back in the Precambrian were the currently dominant species, but from their POV, they certainly trashed the place.
jackd: And see where their lack of responsibility got them. I hope we are smarter than that. ;)
Benjamin Franz wrote: As far as we know, there is no difference between ourselves and the other great apes that is not a question of degree rather than kind.
I can equally well claim that there's no difference between a lion and a housecat that isn't merely a question of degree. Yet they're classified as different genera.
I can also claim just as easily that there's no difference between a dog and a bear that isn't merely a question of degree. Yet they're classified as different families.
I could even claim there's no difference between a blue whale and a harbor porpoise that isn't merely a matter of degree. Yet they're classified in different suborders.
Of course, none of that makes any difference to the facts of the matter. Most evolutionary differences between animals closer than separate Orders, are differences of degree rather than kind. But we don't simply stop classifying at the Order level, do we? No, we distinguish ever finer degrees of differences, and use them to classify into ever smaller clades. So why follow the rules of taxonomy with them, but not with humans?
In any other group of organisms, the differences between human and chimpanzee would be seen as sufficient to justify separate genera at the very least, probably separate subfamilies, possibly separate families. And don't forget all our extinct cousins, the australopithecines and the paranthropines. If humans are genus Pan, then all of those others must be genus Pan too. Paranthropus boisei is a chimpanzee?
Take it in the other direction. If the difference between human and chimp doesn't warrant a separate genus, then why does the difference between chimp and gorilla warrant a separate genus? Between chimp and orangutan? Between chimp and gibbon? Do all the apes fit into a single genus? That makes no more sense than lumping all cats into a single genus, a classification that was abandoned as hopelessly inadequate forty years ago.
I guess my point is this: if you're going to challenge the taxonomic status of humans, then please, use arguments that are scientific!! Prove to me based on the rules of taxonomy and the observed genetics and morphology that chimpanzee and human should be in the same genus. This "we're just another animal, we don't deserve special placement in our own genus" is postmodernist gut-rot. Or rather brain-rot. It reminds me of the Killer Ape Hypothesis that was rampant fifty years ago. That was nonsense. So is this.
wolfwalker said:
To the contrary, in any other group of organisms, Humans and Chimpanzees would have long since been recognized as belonging to the same genus. It is only our desire for 'exceptionalism' that has kept them seperate. Wildman, Uddin, Lie, Grossman and Goodman's 2003 comparative study (1) of Pan Troglodytes showed that placing Pan as distinct from Homo is unjustified by objective measures. Other genera with demonstrably larger differences have long been recongnized.
Those who have attempted to hang their hats on behavioral or locomotive differences are engaging in inconsistent argumentation since by that argument you would need to create a new genus for Urban Man vs Pre-Industrial Man. Utter nonsense.
That they are kept seperate is about politics pre-dating the very existence of the clade system, not science. You need look no further than the Scopes Trial to see the true reasons for the reluctance to group Homo and Pans together. The argument at the genus level is less blatant, but no better founded.
(1) Implications of natural selection in shaping 99.4% nonsynonymous DNA identity between humans and chimpanzees: Enlarging genus Homo
http://www.pnas.org/cgi/content/abstract/100/12/7181?maxtoshow=&HITS=10…
To the contrary, in any other group of organisms, Humans and Chimpanzees would have long since been recognized as belonging to the same genus.
Name some of those "other groups," please.
I'm at least roughly familiar with the taxonomy of most groups of mammals, most North American groups of birds and snakes, and many extinct groups -- primarily vertebrate, but some invertebrate too. Offhand, I can't think of any group in which a level of morphological/behavioral difference similar to that between human and chimpanzee doesn't warrant at least separate genera. I can, however, think of several groups in which a smaller apparent difference is considered to justify separate genera, or even higher clades. Cats, for example: Panthera vs. Felis vs. Neofelis (snow leopard) vs. Smilodon (sabertooth cat) vs. Acinonyx (cheetah). Or birds of prey: the Accipiter hawks vs. the Buteo hawks vs. the several genera of eagles. And is there really any more difference between the gray wolf (Canidae; Canini; Canis lupus) and the red fox (Canidae; Vulpini; Vulpes vulpes) than there is between human and chimp?
wolfwalker:
Equus, for one. The genetic variation within that genus is larger than the difference between Pan and Homo. You have Zebras with 44 chromosomes vs Horses with 64, for example (startlingly, hybrids between the two actually exist). And the split between the species of Equus are of approximately of the same age (give or take a million years ;) ) as the split between Pan and Homo. There is no compelling reason to have the varieties of Equus within a single genus while Pan and Homo, with less genetic difference are split into two.
As for the argument from phenotype - that is only useful when the genetic information is lacking. Otherwise you would be compelled to consider Old English Mastiffs to not only be a seperate species, but a seperate genus from Chihuahuas (I could see an argument for their being tagged as seperate sub-species given the near physical impossibility of sucessfully cross-breeding the two). A ratio of 40 to 1 in body mass (adult Old English Mastiffs weigh between 160 and 340 pounds vs less than 6 pounds for adult Chihuahuas) has to be considered a significant difference.
Note: Yes, I am somewhat tongue in cheek about putting Old English Mastiffs in a different genus than Chihuahuas. But it isn't fundamentally sillier than putting Chimpanzees in a seperate genus from Humans.
I exclude dogs from all discussions of this sort because dogs are an artificial population molded by human fiat. No intelligent hand indulged in selective breeding of chimps and humans. If you have to resort to dogs as an example, I'd say your position is weak enough to be needing some re-evaluation.
As for chromosome count ... [shrug] In some genera of plants, one species has double the number of chromosomes of its closest relative. So what?
My view is this: We know that a small genetic difference between human and chimp produces many obvious phenotypic differences. Yet in other taxas, large genetic differences can produce few phenotypic differences. This demonstrates quite conclusively that there's something going on with the genotype/phenotype relationship that we don't understand yet. Even your own example shows this: horse and zebra (which zebra? Plains, Mountain, or Grevy's?) are genetically compatible enough to produce viable hybrids, even though their chromosome counts differ by up to a factor of two. (horse: 64 chromosomes; Grevy's zebra: 46 chromosomes; plains zebra: 44 chromosomes; mountain zebra: 32 chromosomes) Clearly, a pure genetic analysis is inadequate to fully describe the reality here. Until we figure out what we've been missing, I see no reason to classify based solely on genes.
And once you admit phenotype (including morphology, behavior, preferred habitat, etc.) as a criterion, there can be no doubt that human and chimp deserve at least separate genera.
I don't believe you and I can bridge the gap between our basic assumptions. I am in the genotype is primary camp, you are in the phenotype is primary camp.
I regard discarding dogs as 'artificially selected' to be a copout to avoid recognition that phenotype can only be a secondary guide to figuring taxonomy: Dogs pose no special problem for genotype-is-primary taxonomy.
You appear to regard it as self-evident that species selected by humans cannot be included in consistent taxonomies since there is no easy way to fit their tremendous variation into a phenotype based taxonomy.
I contend that rather than showing that dogs are 'special', it shows that phenotype-is-primary taxonomy is simply inadequate. Pointing to 'artificial' selection is also to insert the 'exceptionalism' of humans as a hidden postulate: Humans aren't 'natural', ergo selection by humans isn't 'natural'.
Our working postulates are too different. I think we will have to just agree to disagree.
I don't believe you and I can bridge the gap between our basic assumptions.
Perhaps not. Some differences in point-of-view are simply too great to find a workable compromise.
I am in the genotype is primary camp, you are in the phenotype is primary camp.
I prefer to think of myself as being in the "evidence is primary" camp. I don't see either genotype or phenotype as being The One True Way. I simply go where the evidence leads. The evidence that I'm aware of tells me that neither a pure-genotype nor a pure-phenotype position can fully explain the reality. Something more is going on. There's a missing piece here. I don't know exactly what it is or where to look for it, but I'm certain it's there, waiting to be found. Until it is, I judge by the evidence I have, not by theories. The evidence I have tells me chimp and human are different enough to rate separate genera.
I regard discarding dogs as 'artificially selected' to be a copout to avoid recognition that phenotype can only be a secondary guide to figuring taxonomy:
I approached this topic in the context of "classification of organisms shaped by natural evolution." That is, after all, what you're trying to do when you try to classify human vs. chimp. Horse and zebra, lion and domestic cat, accipiter and buteo hawks -- all are primarily the products of natural evolution. (The horse and domestic cat are both nearly identical to their nearest wild relatives, so I feel safe in using them as examples.) Dogs aren't. Pure-breed domestic dogs are not the product of natural evolution, any more than domestic crop plants like corn and bananas are. If you restricted your mention of dogs to feral dogs, pariah dogs, dogs that have evolved by natural selection for many generations, then I'd accept them as an example. But not purebreds.