Tag Archives: technology

Quest for fire

1,043-987 thousand years ago

What really distinguishes humans from other animals? We’ve covered some of the answers already, and will cover more in posts to come. But certainly one of the great human distinctions is that we alone use fire. Fire is recognized as something special not just by scientists, but in the many myths about how humans acquired fire. (It ain’t just Prometheus.) Claude Lévi-Strauss got a whole book out of analyzing South American Indian myths of how the distinction between raw and cooked separates nature from culture. (I admit this is where I get bogged down on Lévi-Strauss.)

Until recently the story about fire was that it came late, toward the latter days of Homo erectus. But Richard Wrangham, a primatologist at Harvard, turned this around with his book Catching Fire (which is not the same as this book), arguing that the taming of fire goes back much earlier, to the origin of Homo erectus. Wrangham argues that it was cooking in particular that set us on the road to humanity. Cooking allows human beings to extract much more of energy from foods (in addition to killing parasites). Homo erectus had smaller teeth and jaw than earlier hominins and probably a smaller gut, and it may have been fire that made this possible. Cooking is also likely to have affected social life, by focusing eating and socializing around a central place. (E O Wilson thinks that home sites favored intense sociality in both social insects and humans.)

Surviving on raw food is difficult for people in a modern high-tech environment and probably impossible for people in traditional settings. Anthropologists are always looking for human universals, and almost always finding exceptions (e.g. the vast majority of societies avoid regular brother-sister marriage, but there are a few exceptions). But cooking seems to be a real, true universal. No society is known where people got by without cooking. Tasmanians, isolated from the rest of the world for 10,000 years, with the simplest technology of any people in recent history, had lost the art of making fire, but still kept fires going and still cooked.

Recent archeological finds have pushed the date for controlled use of fire back to 1 million years ago (see today’s tweet on Wonderwerk cave), but not all the way back to the origin of Homo erectus. This doesn’t mean Wrangham is wrong. Fire sites don’t always preserve very well: we have virtually no archeological evidence of the first Americans controlling fire, but nobody doubts they were doing it. It could be that it will be the geneticists who will settle this one. The Maillard (or browning) reaction that gives cooked meat much of its flavor generates compounds that are toxic to many mammals but not (or not so much) to us. At some point we may learn just how far back genetic adaptations to eating cooked food go.

An alternative to an early date for fire, there is the recent theory that processing food, by chopping it up and mashing it with stone tools, was the crucial early adaptation.

Whenever it is exactly that humans started cooking, the date falls in (Northern hemisphere) grilling season on Logarithmic History, so you can celebrate the taming of fire accordingly. It doesn’t have to be meat you grill. Some anthropologists think cooking veggies was even more important. I recommend sliced eggplant particularly, brushed with olive oil to keep it from sticking, and with salt, pepper, and any other spices.

And here, if it’s your kind of thing, is Iron Maiden doing Quest for Fire.


My handaxe

1.31-1.24 million years ago

By today’s date, Acheulean tools are well developed in Africa, and found in India too. Sophisticated tools like the Acheulean hand axe probably tell us something not just about cognition in relation to tool making, but also about social cognition. You wouldn’t make a hand axe, use it, and abandon it. Nor would you go to all the trouble if the biggest, baddest guy in the group was immediately going to grab it from you. So there is probably some notion of artifacts-as-personal-possessions by the time Acheulean appears.

Possession is a social relationship, a relationship between two or more individuals with respect to the thing possessed. Robinson Crusoe didn’t “own” anything on his island before Friday came along.

Linguists have noted something interesting about the language of possession that maybe tells us something about the psychology of possession: Expressions for possession are often similar to expressions for spatial locations. Compare spatial expressions:

João went to Recife.
Chico stayed in Rio.
The gang kept Zezinho in Salvador.

and corresponding constructions for possessions:

The Crampden estate went to Reginald.
The Hampden estate stayed with Lionel.
Thag kept axe.

Of course the Crampden estate didn’t go anywhere in physical space, but it still traveled in the abstract social space of possession. In some cases just switching from inanimate to animate subject will switch the meaning from locative to possessive. The Russian preposition y means at/near when applied to a place (People are at Nevsky street) but possession when applied to a person (Hat is “at” Ivan = Ivan has hat.)

What may be going on here: people (and many other creatures) have some mental machinery for thinking about physical space. That machinery gets retooled/borrowed/exapted for thinking about more abstract relationships. So the cognitive psychology of space gets retooled for thinking about close and distant social relationships, or time ahead and behind. In other words, we may be seeing a common evolutionary phenomenon of organs evolved for one purpose being put to another purpose – reptile jaw bones evolve into mammalian inner ear bones, dinosaur forelimbs evolve into bird wings. You can find Steve Pinker making this argument in his book The Stuff of Thought. For a while most of the evidence of repurposing spatial cognition for more abstract relationships came from linguistics, but there’s now some corroboration from neurology.

And I’ve made the argument for the particular case of kinship: regularities in kin terminology across cultures tell us something about pan-human ideas of “kinship space.” (My kin and mybody parts are arguably the most basic, intrinsic primitive sorts of possessions, since long before my handaxe.) This implies that the evolutionary psychology of kinship has not just an adaptive component (adaptations for calculating coefficients of relatedness and inbreeding), but also a phylogenetic component  (homologies with the cognitive psychology of space).

We’ll see other possible examples, involving e.g. the evolution of speech sounds, as we move along.


1.54-1.47 million years ago

From around 1.4 million years ago, Acheulean hand axes appear in Africa. They will eventually show up in southwest Europe and as far east as India. Hand axes were long thought to be absent from further east, but now have been found sporadically in East Asia. (Bamboo might have been an alternative to stone in the east.) Wear analyses show that hand axes, “the Swiss Army knife of the Paleolithic,” were used for a variety of purposes: cutting wood, slicing meat, scraping hides.

The hand axe implies a great leap forward cognitively from earlier Oldowan tools (although you can flay an elephant with Oldowan flakes). People (let’s call them people) were not just choosing the right material and making the right hand movements, but choosing the right shape of stone, and imagining the hand axe inside it before they started.

Dietrich Stout, an experimental anthropologist at Emory University, has trained students to make modern-day Acheulean handaxes, and monitored their brains as they learn. (The students’ axes, after months of practice, still aren’t as good as the real thing.) See the video below:

Coals to Newcastle

339-321 Mya

It seems like Gaia really went on a bender in the late Carboniferous, getting drunk on oxygen. By some estimates, the atmosphere was over 30% oxygen back then, compared to 21% today. Living things took advantage of the opportunity. Insects apparently face an upper limit in size because they rely on diffusion through tracheas instead of forced respiration through lungs to get oxygen into their bodies. With more oxygen in the air, this limit was raised. The Carboniferous saw dragonflies with a wingspan up to 70 centimeters, and body lengths up to 30 centimeters, comparable to a seagull.


This happened because plants were turning carbon dioxide into organic matter and free oxygen, and the organic matter was accumulating. With carbon dioxide being removed from the atmosphere, the late Carboniferous and subsequent early Permian saw a reduced greenhouse effect, and global cooling. This was another Ice Age, with ice caps around the southern pole.

A lot of organic carbon ended up being buried. Much of the world’s coal, especially high quality anthracite, has its origin in Carboniferous tropical forests. Western Europe and eastern North America lay in the tropics at the time, and got a particularly generous allotment of coal. Three hundred million years later this bounty would fuel the early Industrial Revolution. (Thanks partly to some of my Welsh ancestors, who helped dig it up back in the day.)

coal age

The curve of binding energy

More stardust

Looking at the abundance of different elements in the universe, we get the following:

element abundances

Note that the vertical scale is logarithmic, so there is vastly more hydrogen and helium in the universe than any other element. As noted in the last post, all the elements except hydrogen and helium were formed after the Big Bang, spewed out by supernovas and the collisions of neutron stars. In general, heavy elements are less abundant because it takes more steps to produce heavy elements than light ones. But the curve is not smooth. The lightest elements after hydrogen and helium (lithium, beryllium, boron) are relatively rare, because they get used up in the nucleosynthesis of heavier elements. And there is a saw tooth pattern in the chart, because nucleosynthesis favors atoms with even numbers of protons. So we get lots of oxygen, magnesium, silicon, and iron, the main constituents of our planet. Lots of carbon too. Finally, iron (Fe) is more than 1000 times more abundant than might be expected based on a smooth curve. Iron nuclei are especially stable because binding energy, the energy that would be required to take the nucleus apart into its constituent protons and neutrons, reaches a maximum with iron. Here’s the famous curve of curve of binding energy (nucleons are protons and neutrons):

curve of binding energy

An implication of this curve is that if you can split a really heavy nucleus, of Uranium-235 say, into smaller nuclei (but still heavier than iron), you will release energy equal to the vertical difference between U-235 and its lighter fission products (not shown) on the vertical scale. This is lots of energy, way more than you get from breaking or forming molecular bonds in ordinary chemical reactions. And if you can fuse two light nuclei, of hydrogen say, into a larger nucleus, you can get even more energy. When we split uranium, we are recovering some of the energy that a star put into synthesizing elements heavier than iron, before or as it went supernova. When we fuse hydrogen, we are extracting energy from the Big Bang that no star got around to releasing.

Starting to figure this all out was part of a scientific revolution that made physics in 1950 look very different from physics in 1900. The new physics resolved a paradox in the study of prehistory. Geologists were pretty confident, based on rates of sedimentation, that the Earth had supported complex life for hundreds of millions of years. But physicists couldn’t see how the sun could have kept shining for so long. The geologists were right about deep time; it took new physics to understand that the sun got its energy from fusing hydrogen to helium (via some intermediate steps).

As the scientific revolution in atomic physics was picking up steam, it was natural to assume that it would be followed by a revolution in technology. After all, earlier scientific revolutions in the understanding of masses and gases, atoms and molecules, and electrons and electromagnetism, had been followed by momentous innovations in technology: the steam engine, artificial fertilizers, electrification, radio, to name just a few. But in some ways, the Atomic Age hasn’t lived up to early expectations. The atom bomb brought an earlier end to the Second World War, but didn’t change winners and losers. The bomb was never used again in war, and it’s a matter for debate how much the atom bomb and the hydrogen bomb changed the course of the Cold War. Nuclear energy now generates a modest 11% of the world’s electricity (although this number had better go up in the future if we’re serious about curbing carbon dioxide emissions). And a lot of ambitious early proposals for harnessing the atom never got anywhere. Project Plowshare envisioned using nuclear explosions for enormous civil engineering projects, digging new caves, canals, and harbors. Even more audacious was Project Orion, which developed plans for a rocket propelled by nuclear explosions. Some versions of Orion could have carried scores of people and enormous payloads throughout the solar system. Freeman Dyson, a physicist who worked on the project, said “Our motto was ‘Mars by 1965, Saturn by 1970.’”

On the purely technical side these plans were feasible. There were concerns about fallout, but the problems were not insurmountable. Nevertheless both Plowshare and Orion were cancelled. Dyson said “… this is the first time in modern history that a major expansion of human technology has been suppressed for political reasons.” The history of the Atomic Age  and its missed opportunities is a refutation of pure technological determinism. How or even whether a new technology is exploited depends on social institutions, politics, and cultural values.

Steam engine time


The steam engine was a child of seventeenth century science; the Scientific Revolution gave birth to the Industrial Revolution. That’s not at all the conventional story, but David Wooton’s recent book The Invention of Science: A New History of the Scientific Revolution makes the case.

According to the conventional story, the steam engine resulted from the work of generations of inspired tinkerers, ingenious craftsmen with no particular scientific training and no great scientific knowledge. Indeed, according to one historian, “Science owes more to the stream engines than the steam engine owes to science.” (After all, the steam engine did inspire Carnot’s thermodynamic theory.)

But Wooton traces a path from scientific theory to practical application, beginning with the seventeenth century science of vacuum, air and steam pressure. The pioneering scientists here were not just theorists. They built (or at least designed) a number of devices for making use of differences in gas pressures, including an air gun (Boyle), a steam pressure pump (della Porta), and a vacuum-powered piston (von Guericke). Huygens took up the last idea, using an explosion to empty air from a cylinder, through a valve, and then using the partial vacuum to move a piston. This in turn was taken up by Denis Papin, a French Protestant medical doctor and mathematician, who worked as an assistant to Huygens, and then to Boyle. Papin combined scientific knowledge and engineering experience to design several steam engines. None of these was very practical – sadly Papin ended his life in failure and poverty. But the first of them was very similar to the first commercially viable steam engine, produced by Newcomen in 1712 – so similar that many historians have been convinced that Newcomen must have been familiar with Papin’s design.

Up to recently there’s been no convincing account of how Newcomen could have learned of Papin. But now Wooton has discovered the likeliest link, a book by Papin with the unpromising title A Continuation of the New Digester of Bones. The book has been neglected by historians, not surprisingly, but sold well in its own day. It gives plans for a pressure cooker (hence the title). But it also contains detailed descriptions both of vacuum powered piston, and of the use of steam condensation to produce a vacuum: just what Newcomen needed to put together to build his first engine. Wooton writes:

Newcomen’s steam engine is a bit like a locked-room plot in a detective story. Here is a dead body in a locked room: How did the murderer get in and out, and what did he use as a weapon? … We cannot exclude the possibility that Newcomen went to London and met Papin in 1687 … But we do not need to imagine such a meeting. With a copy of the Continuation in his hands, Newcomen would have known almost everything that Papin knew about how to harness atmospheric pressure to build an engine. … From this unintended encounter, I believe, the steam engine was born.

He concludes:

Historians have long debated the extent to which science contributed to the Industrial Revolution. The answer is: far more than they have been prepared to acknowledge. Papin had worked with two of the greatest scientists of the day, Huygens and Boyle. He was a Fellow of the Royal Society and a professor of mathematics. … Newcomen picked up … where Papin began. In doing so he inherited some of the most advanced theories and some of the most sophisticated technology produced in the seventeenth century. … First came the science, then came the technology.

Little deuce coupe, a prehistory


Wheels probably started being used by copper miners in southeastern Europe, in the Carpathians, in the 4th millennium BC. The early wheels were wheelsets, with the wheel fixed solidly to an axle, and the axle rotating. For miners, any alternative to carrying loads of ore on their backs must have been welcome. Miners can smooth a path for their carts, so the problem of moving wheels on uneven terrain is reduced.

Several centuries later, somewhere between the Carpathians and the steppe country north of the Black Sea, another kind of wheel was developed, with the wheel rotating freely around a fixed axle. The new wheel was perfectly suited to a new way of life that developed on the steppes, where nomads followed herds of livestock. Horses might have been the flashiest part of the new lifestyle, but oxcarts, carrying family belongings from one grazing site to another, may have been just as important.

Judging by their reconstructed vocabulary, speakers of Proto-Indo-European – the ancestor of most of the languages of Europe and Northern India – were among those adopting the new technology.


(Actually, looking at the reconstructions, it looks like the adoption of the wheel may have come after Proto-Anatolian – ancestor to Hittite – had branched off from other Indo-European languages.)

Some cultures got into wheels more than others. Sub-Saharan African societies, even including cattle nomads, never adopted the wheel. In the Middle East, wheeled vehicles gave way pack camels sometime between Roman times and the Islamic period. As a result, Islamic states didn’t have to put as much effort into road building as earlier states, and the narrow streets of Islamic cities were made for camels, not carts, to traverse. Wheeled transportation was limited in Japan. And in the New World, wheels are known only from children’s toys.


Things were different in Europe and its cultural offshoots, where wheeled vehicles have exercised a hold on the imagination – especially the male imagination – right up to the present. This is from Richard Bulliet’s recent book, The Wheel: Inventions and Reinventions (p. 33):

Not only is the world racing fraternity composed almost entirely of men, but it has historically recruited very few drivers from East Asia, South Asia, the Middle East and Africa. …[T]he five-thousand-year history of wheels in Indo-European societies – specifically in Europe, including its former colonies, and North America – testifies to an affinity between vehicle driving and male identity in cultures that descend from the Proto-Indo-European linguistic tradition. Since the earliest days of wagon nomads and chariots, through the carriage revolution of the sixteenth century, and down to the automobile era, men brought up in European (and Euro-American) societies have repeatedly linked their manhood to their vehicles.