Archaeologist and anthropologist Timothy Taylor explains how a long-vanished artefact explains human evolution and led to "survival of the weakest."
You begin your book The Artificial Ape by claiming that Darwin was wrong. In what way?
Darwin is one of my heroes, but I believe he was wrong in seeing human evolution as a result of the same processes that account for other evolution in the biological world - especially when it comes to the size of our cranium.
Darwin had to put large cranial size down to sexual selection, arguing that women found brainy men sexy. But biomechanical factors make this untenable. I call this the smart biped paradox: once you are an upright ape, all natural selection pressures should be in favour of retaining a small cranium. That's because walking upright means having a narrower pelvis, capping babies' head size, and a shorter digestive tract, making it harder to support big, energy-hungry brains. Clearly our big brains did evolve, but I think Darwin had the wrong mechanism. I believe it was technology. We were never fully biological entities. We are and always have been artificial apes.
So you are saying that technology came before humans?
The archaeological record shows chipped stone tool technologies earlier than 2.5 million years ago. That's the smoking gun. The oldest fossil specimen of the genus Homo is at most 2.2 million years old. That's a gap of more than 300,000 years - more than the total length of time that Homo sapiens has been on the planet. This suggests that earlier hominins called australopithecines were responsible for the stone tools.
Is it possible that we just don't have a genus Homo fossil, but they really were around?
Some researchers are holding out for an earlier specimen of genus Homo. I'm trying to free us to think that we had stone tools first and that those tools created a significant part of our intelligence. The tools caused the genus Homo to emerge.
How do we know the chipped stones were used as tools?
If you wanted to kill something or to defend yourself, you don't need a chipped stone tool - you can just pick up a rock and throw it. With chipped stone, something else is going on, something called "entailment": using one thing to make another. You're using some object to chip the stone into a particular shape with the intention of using it for something else. There's an operational chain - one tool entails another.
What were these tools used for?
Upright female hominins walking the savannah had a real problem: their babies couldn't cling to them the way a chimp baby could cling to its mother. Carrying an infant would have been the highest drain on energy for a hominin female - higher than lactation. So what did they do? I believe they figured out how to carry their newborns using a loop of animal tissue. Evidence of the slings hasn't survived, but in the same way that we infer lungs and organs from the bones of fossils that survive, it is from the stone tools that we can infer the bits that don't last: things made from sinew, wood, leather and grasses.
How did the slings shape our evolution?
Once you have slings to carry babies, you have broken a glass ceiling - it doesn't matter whether the infant is helpless for a day, a month or a year. You can have ever more helpless young and that, as far as I can see, is how encephalisation took place in the genus Homo. We used technology to turn ourselves into kangaroos. Our children are born more and more underdeveloped because they can continue to develop outside the womb - they become an extra-uterine fetus in the sling. This means their heads can continue to grow after birth, solving the smart biped paradox. In that sense technology comes before the ascent to Homo. Our brain expansion only really took off half a million years after the first stone tools. And they continued to develop within an increasingly technological environment.
You write in the book that this led to a "survival of the weakest". What does this mean?
Technology allows us to accumulate biological deficits: we lost our sharp fingernails because we had cutting tools, we lost our heavy jaw musculature thanks to stone tools. These changes reduced our basic aggression, increased manual dexterity and made males and females more similar. Biological deficits continue today. For example, modern human eyesight is on average worse than that of humans 10,000 years ago.
Unlike other animals, we don't adapt to environments - we adapt environments to us. We just passed a point where more people on the planet live in cities than not. We are extended through our technology. We now know that Neanderthals were symbolic thinkers, probably made art, had exquisite tools and bigger brains. Does that mean they were smarter?
Evidence shows that over the last 30,000 years there has been an overall decrease in brain size and the trend seems to be continuing. That's because we can outsource our intelligence. I don't need to remember as much as a Neanderthal because I have a computer. I don't need such a dangerous and expensive-to-maintain biology any more. I would argue that humans are going to continue to get less biologically intelligent.
If you said to me, you can either have your toes cut off or your whole library destroyed, with no chance of ever accessing those works again, I'd say "take my toes" - because I can more easily compensate for that loss. Of course, you could get into a grisly argument over how much of my biology I'd give up before I'd say, "OK, take the Goethe!"
Is human technology really any different from, say, a bird's nest, a spider's web or a beaver's dam?
Some biologists argue that human culture and technology is simply an extension of biological behaviours and in that sense humans are like hermit crabs or spiders. That's an idea known as "niche adaptation". I see human technology as different because of the notion of entailment. A number of philosophers and social anthropologists have argued that the realm of artifice has its own logic - an idea that traces back to Kant's idea of the autonomy of the aesthetic realm. Philosophy, art history and paleoanthropology have to all come together for us to understand who we are.
The point is, the realm of artificial things - that is, technology - has a different generative pattern than the Darwinian pattern of descent with modification. People like to argue that you can apply Darwinian selection to, say, industrial design. That led Richard Dawkins to propose and Susan Blackmore to develop the "meme" idea - cultural analogues of genes that are not biological but they are still replicators and follow the basic logic of biological evolution.
I would argue that memes simply don't make sense. And the reason is that when you look at an artificial object like a chair, for instance, there is no central rule that defines it. There is no way to draw a definite philosophical boundary and say, here are the characteristics that are both necessary and sufficient to define a chair. The chair's meaning is linguistic and symbolic - a chair is a chair because we intend for it to be a chair and we use it in a particular way. Artificial objects are defined in terms of intention and entailment - and that makes artificial things very different from biological things.
People like Ray Kurzweil talk about an impending singularity, when technology will advance at such a rapid pace that it will become intelligent and the world will become qualitatively different. Do you agree?
I am sympathetic to Kurzweil's idea because he is saying that intelligence is becoming technological and I'm saying, that's how it's been from the start. That's what it is to be human. And in that sense, there's nothing scary in his vision of artificial intelligence. I don't see any sign of intentionality in machine intelligence now. I'm not saying it will never happen, but I think it's a lot further away than Kurzweil says.
Will computers eventually be able to develop their own computers that are even smarter than them, creating a sudden acceleration that leaves the biological behind and leaves us as a kind of pond scum while the robots take over? That scenario implies a sharp division between humans and our technology, and I don't think such a division exists. Humans are artificial apes - we are biology plus technology. We are the first creatures to exist in that nexus, not purely Darwinian entities. Kurzweil says that the technological realm cannot be reduced to the biological, so there we agree.
At the end of the book, you note that there is no "back to nature" solution to climate change. Does that mean our species was doomed from the start?
The point is, we were never fully biological entities, so there is no "nature" to go back to, for us. Wait, you might ask, what about people who "live in nature", people like the Aborigines in Tasmania? In fact, the Tasmanians used technology to adapt and survive and they might have done that for maybe another 40,000 years. The issue is that their type of technology - non-entailed - is not the way humans will survive in the final scenario. Ultimately we need major progress - because even without climate change, the sun is eventually going to blow up.
Now, you might think that's a ridiculously long time away, but that's the kind of ridiculous timescale palaeoanthropologists think about. I look back 4 million years and see our emergence and our evolution and then I look forward 4 million years because those are the timescales I'm used to. And in the long run, humans will go extinct if we can't get off this planet. The only way out, ultimately, is up. The Tasmanians didn't have the kind of technology that would lead them there, but we do.
Timothy Taylor is an archaeologist and anthropologist at the University of Bradford, UK. His book The Artificial Ape: How technology changed the course of human evolution is published by Palgrave Macmillan this month.
(Image: Becca Wright)