This week, scientists announced the discovery of a human-like species, whose remains were found deep in a cave in South Africa. Named naledi, the researchers believe the species could date back three million years and be the first of the genus to which we belong—Homo—and thus might teach us something important about humanity's evolution and ancestry.
Such discoveries always generate huge attention, in part because they lead us to ask fundamental questions about what it is that defines us. With that in mind, we asked our panel to tell us what they think a human is.
From a palaeoanthropological perspective, a human is an individual who displays the biological and behavioural characteristics that define our species, Homo sapiens. Biologically, this means having a large and sophisticated brain, small teeth and jaws (since we cook much of our food or process it outside of our mouths), long legs that make us efficient at walking, and dexterous hands that allow us to manipulate objects in our environment. Behaviourally, this means we have complex culture, symbolic and abstract thought, and the ability to conceive and produce complex tools to assist us in our daily lives. We are a unique species on the planet today, but like all animals we have an evolutionary history. The goal of palaeoanthropology is to reconstruct that history, through the study of fossils and archaeological remains, and determine when, where and why the biological and behavioural characteristics that define us as humans emerged.
Definitions abound: a political animal (Aristotle); a laughing animal (Thomas Willis); a tool-making animal (Benjamin Franklin); a religious animal (Edmund Burke); a cooking animal (James Boswell); monkeys with guns and money (Tom Waits). I’ll go for an animal with remarkable feet. Combined with adaptations to the legs, hips and back, they give us remarkable stability, agility and endurance on the ground, which in turn allowed for the evolution of ways to manipulate, carry and throw in ways no other animal can. Like other species in our genus, Homo naledi had feet very like ours. It should be no surprise that all kinds of astonishing things follow.
The human is the animal that asks questions. It’s a function of having a brain that is more evolved than is strictly necessary for survival. Our excess mental capacity goes into questioning, and this is the origin of science, of exploration, of creativity in general. But as much as questioning drives us forward, it also means that uncertainty is fundamental. We live in a constant state of imperfect knowledge. The human is the creature with more questions than answers.
New discoveries about the origins of humanity are always fascinating. But for human geographers it is what happened after that is of greatest interest. What happened after humans began to use fire, cook meat, develop language and became modern?
Humans are a very recent species. In geological time we have not spent very long apart. We know a great deal about when people first arrived in far flung places; when we first reached South America, Madagascar and New Zealand. However, in much of Asia the criss-crossing of many migratory waves leaves a far more confused archeological record. We can't be sure of precisely when we first left Africa. We know that cold and unattractive North West Europe was settled late, at least until long after the ice had melted. What we do know is that international migration is bringing humanity back together again.
This has all the elements of a fabulous story: crowdsourced explorers, claustrophobic caving, one of the most remarkable paleontological hauls ever, and the potential to hugely enrich and complicate the picture of human origins. As yet, it's not much more than a story though: we need to know, in particular, the age of these fossils, and to figure out where they sit on the hominin evolutionary tree. Forget "missing links" (if you haven't already); it seems likely that Homo naledi will show early human origins to have been a complex mosaic of overlapping and coexisting species.
Read more from Philip Ball: Science is fallible, just like us Why the Poohsticks formula is wrong Is Nasa about to discover alien life?
This week's Big Question was edited by Josh Lowe and Sadie Levy Gale
Such discoveries always generate huge attention, in part because they lead us to ask fundamental questions about what it is that defines us. With that in mind, we asked our panel to tell us what they think a human is.
A unique species
Matthew Skinner—senior lecturer in biological anthropology at Kent UniversityFrom a palaeoanthropological perspective, a human is an individual who displays the biological and behavioural characteristics that define our species, Homo sapiens. Biologically, this means having a large and sophisticated brain, small teeth and jaws (since we cook much of our food or process it outside of our mouths), long legs that make us efficient at walking, and dexterous hands that allow us to manipulate objects in our environment. Behaviourally, this means we have complex culture, symbolic and abstract thought, and the ability to conceive and produce complex tools to assist us in our daily lives. We are a unique species on the planet today, but like all animals we have an evolutionary history. The goal of palaeoanthropology is to reconstruct that history, through the study of fossils and archaeological remains, and determine when, where and why the biological and behavioural characteristics that define us as humans emerged.
Remarkable feet
Caspar Henderson—author of "The Book of Barely Imagined Beings: A 21st Century Bestiary"Definitions abound: a political animal (Aristotle); a laughing animal (Thomas Willis); a tool-making animal (Benjamin Franklin); a religious animal (Edmund Burke); a cooking animal (James Boswell); monkeys with guns and money (Tom Waits). I’ll go for an animal with remarkable feet. Combined with adaptations to the legs, hips and back, they give us remarkable stability, agility and endurance on the ground, which in turn allowed for the evolution of ways to manipulate, carry and throw in ways no other animal can. Like other species in our genus, Homo naledi had feet very like ours. It should be no surprise that all kinds of astonishing things follow.
Asking questions
Robert Rowland Smith—philosopherThe human is the animal that asks questions. It’s a function of having a brain that is more evolved than is strictly necessary for survival. Our excess mental capacity goes into questioning, and this is the origin of science, of exploration, of creativity in general. But as much as questioning drives us forward, it also means that uncertainty is fundamental. We live in a constant state of imperfect knowledge. The human is the creature with more questions than answers.
Together again
Danny Dorling—Halford Mackinder professor of geography at Oxford UniversityNew discoveries about the origins of humanity are always fascinating. But for human geographers it is what happened after that is of greatest interest. What happened after humans began to use fire, cook meat, develop language and became modern?
Humans are a very recent species. In geological time we have not spent very long apart. We know a great deal about when people first arrived in far flung places; when we first reached South America, Madagascar and New Zealand. However, in much of Asia the criss-crossing of many migratory waves leaves a far more confused archeological record. We can't be sure of precisely when we first left Africa. We know that cold and unattractive North West Europe was settled late, at least until long after the ice had melted. What we do know is that international migration is bringing humanity back together again.
Complex origins
Philip Ball—science writer and Prospect bloggerThis has all the elements of a fabulous story: crowdsourced explorers, claustrophobic caving, one of the most remarkable paleontological hauls ever, and the potential to hugely enrich and complicate the picture of human origins. As yet, it's not much more than a story though: we need to know, in particular, the age of these fossils, and to figure out where they sit on the hominin evolutionary tree. Forget "missing links" (if you haven't already); it seems likely that Homo naledi will show early human origins to have been a complex mosaic of overlapping and coexisting species.
Read more from Philip Ball: Science is fallible, just like us Why the Poohsticks formula is wrong Is Nasa about to discover alien life?
This week's Big Question was edited by Josh Lowe and Sadie Levy Gale
