Deborah Netburn of Los Angeles Times recently interviewed Don Johanson, the discoverer of the important ape-woman Lucy (Australopithecus afarensis) forty years ago. It is reported here on phys.org news.
Here, I report some of the interview, and insert comments. Below is the standard but outdated view held by Johanson:
J: In the early 1970s … [m]ost people thought our most primitive origins were in Africa, but where we really became human was Europe.
N: How did the discovery of Lucy change that?
J: She shifted, very dramatically, anthropologists’ view of where we obtained our human features. She showed us it happened in Eastern Africa, and more specifically in the Afar region of Ethiopia where she was found.
1: “She showed us [dramatically] … [it happened in Eastern Africa].”
That’s a claim of proof. ‘So what’s wrong with claiming proof?’ you might retort. Well, so this:
Ж9) “There are no absolute facts, proofs or truths; outside mathematics at least, they are convenient untruths that can simplify our thinking. Proof needs to demonstrate the impossibility of any competing theory, known or not, of equivalent or superior power, whereas disproof merely requires the presentation of evidence inconsistent with the one theory. Knowledge is beliefs, not facts.”
And it’s not just that proof is technically impossible in natural science but that it’s a classic Pooh-trap for heffalumps: It’s exactly there that your science is most likely to go wrong…and where others can come along later and show you up.
Like now for example! It’s not just that you might group your concepts into a false statement, but your underlying concepts might no longer be valid. How many angels can dance on a pin in the 21st century? Not as many as in the midddle ages, I’d guess.
Johanson is right to claim proof if:… Lucy does display those crucial features and they are the right ones, and… she is the first, and… no others did it in parallel, and… she didn’t evolve elsewhere then move to Afar, and… etc.
Don’t trust me on that, trust a sometime Harvard anthropologist and subsequent spinal surgeon, Aaron Filler. You can tell me you understand more about spines than him, but if you tried to tell yourself that, would you really believe it? Upright walking goes back to not long after we lost our tails.
And, there are two stages of upright walking:
Efficient human style, starting with the first Australopithecine (NOT Lucy! but Aus. anamensis – and Johanson should have known that),
…and the earlier waddling, a bit like gibbons perhaps. Our ancestral line did this from Ardipithecus ramidus ramidus about 4-4.3mya all the way back to Morotopithecus 15-20mya.
3: Every discoverer likes to imagine their fossil is the first human
– unless they think it’s the first bird, or the first domestic dog, or the first animal to walk on land, or whatever. Do a statistical check if you want and see how often this happens. And of course, even if it isn’t the first human, it DEFINITELY IS ALWAYS on the human lineage. Other people’s fossils might be dead-ends on the human bush BUT YOURS ISN’T! NO SIRREE!
It’s because of not appreciating point 2, and being tempted into the error in point 3 that the temptation, always to be resisted, of making the point 1 error, claiming proof, caught him.
He may be right that people thought that way after Lucy was found, but saying it was right meant he made the error himself.
J: She [Lucy] also allowed us to say conclusively that upright walking went back as much as 3.5 million years. That was a major leap in our understanding of the sequence of events of human evolution.
But not understanding that upright walking actually goes back 15-20 million years is a major pitfall in understanding human evolution. He’s not speaking here before the Ardi publications in 2009 (free download!), but two weeks ago!
J: Lucy’s body still had relatively short legs and relatively long arms, which is the kind of anatomy we see in more tree-living or arboreal species
J: So she was an important bridge for us between more ancient sorts of things and more modern sorts of things.
Or you might say her intermediate form is consistent with being an intermediate bridge from pre-human to human… or it is also consistent with her being an intermediate bridge from the state of the human linage 4mya, towards the chimp condition. (Not “back to the chimp condition” since none of Lucy’s ancestors knuckle-walked.)
J: Walking upright had the advantage of freeing the forelimbs from locomotor needs, allowing them to be used for other things, like carrying food back to a home base and sharing it with members of one’s own tribe or band.
We don’t know what all the benefits were, but it was obviously a major landmark breakthrough.
…and of course if that wasn’t when we became upright, it wasn’t done in order to carry things… and the better theory would be that we just became more efficient because we had to do a lot more walking.
N: Are there major holes in the story of our origins that you would especially like to see filled in?
J: At the Institute of Human Origins we are working to answer the specific question: What are the evolutionary foundations of modern humans?
if so, why aren’t you seeking the answers by imagining, seeking and listing all the plausible theories and carefully and HONESTLY evaluating them? Because you’re not.
N: Some people feel that the world has been picked over, and there is nothing left to discover. Do you agree?
J: One of the changes in paleoanthropology that is so healthy is a switch from discovery-driven to a much more introspective level of scientific research.
It would be if you were really doing it. Try thinking of science as being theory-driven. That might help.
Oddly, instead of his next comments enlarging on some kind of genuine introspective approach, he says:
J: There are thousands of fossils in vaults throughout the world that have only been superficially studied. We can now look at trace elements and see what diets were like, or use CT scans to look at tooth formation and what it can tell us about life histories.
We also have geological deposits throughout Africa that have not been thoroughly examined and I think new discoveries will be made and be surprising.
Looks to me like he’s still doing discovery-led thinking but claiming he isn’t.
J: As I tell my students, you are only limited by your imagination.
Insert joke here.