How did everything begin? This is the first question faced by any creation myth and, despite the achievements of modern cosmology, answering it remains tricky.

At the very beginning, all explanations face the same problem: how can something come out of nothing? The problem is general, for beginnings are inexplicable. At the smallest scales, subatomic particles sometimes emerge instantaneously from nothingness. One moment there is nothing; the next moment there is something. There is no in-between state. Quantum physics can analyze these odd jumps into and out of existence with great precision, but it cannot explain them in ways that...

Look at the sky on a clear night, and it seems obvious that stars are the most important inhabitants of our universe. But stars, like humans, do not exist in isolation. They gather into the huge cosmic societies we callgalaxies,each of which may contain 100 billion stars. Our home galaxy is the Milky Way. Unlike other galaxies, which appear to us as faint stars or blurs, the Milky Way looks like a pale river of light flowing across the night sky, because we see it from inside. What is less obvious to the naked eye, and was not...

The previous two chapters surveyed regions so vast that light can take billions of years to cross them and the stars they contain may be as numerous as grains of sand on a beach. Toward the end of chapter 2, we zoomed in on one region of a single galaxy, the Milky Way. In this chapter, we shift to a more intimate scale, that of a single star and one of its planets. On this tiny scale, we think of our local star as “the Sun”—and it seems to dominate our universe. So it is not surprising that many...

“What is life?” The physicist Erwin Schrödinger asked this question in a famous series of lectures given in Dublin in 1943. Schrödinger’s answer was remarkably prescient, for he wrote before we had any real understanding of the genetic basis of life. He argued that we should be able to explain life as scientifically as we can explain physics or chemistry. But he also understood that we cannot define life simply by referring to a checklist. Like all complex entities, living organisms manage significant flows of energy and matter, so they must have some form of metabolism. They take in and...

Once life had appeared on Earth, natural selection ensured that living organisms would multiply and diversify as long as they could find new niches to fill in a changing world. This chapter will describe the main changes in the history of life on Earth. How did evolution generate the variety of organisms present today? What are the main stages in the history of life on Earth? Though many details of this story remain obscure, its broad outlines are now remarkably clear.

After almost 4 billion years of evolution, most living organisms are still simple and small. Bacteria rule, as they...

The rest of this book will be concerned mainly with the history of just one species,Homo sapiens.There are two justifications for narrowing the focus in this way. The first is that we—the author and readers of this book—belong to this species. To know ourselves, we must know the history ofHomo sapiens.The second reason, less obvious and less parochial, is that the history of our species is significant at some surprisingly large scales.

When we try to explain theappearanceof human beings, we face once again the paradox of beginnings. How can something utterly...

Many features contributed to the unique evolutionary package that is our species. But the previous chapter argued that the most critical was the appearance of symbolic language, which released the new and uniquely potent adaptive mechanism of collective learning. So, to understand when human history really began, we have to understand when and how humans acquired their aptitude for symbolic language.

This is murky territory, for language leaves no direct signs in the fossil record; our attempts to understand the evolution of human language depend on ambiguous hints in the fossil record, padded out with a heavy wadding of theory....

In the geological timescale, the Pleistocene era ends and the Holocene era begins ca. 11,500 years ago, at the end of the last ice age. From about this time, human history sets out in a new direction. A threshold is crossed, with a shift from extensive to intensive technologies. In the Paleolithic era, the increasing ecological power of our species shows up in the exploration of new environments during migrations that took humans around the world. From the early Holocene, it takes the form ofintensification:new technologies and lifeways that enabled humans to extract more resources from a given...

In the early universe, gravity took hold of clouds of atoms, and sculpted them into stars and galaxies. In the era described in this chapter, we will see how, by a sort of social gravity, cities and states were sculpted from scattered communities of farmers. As farming populations gathered in larger and denser communities, interactions between different groups increased and the social pressure rose until, in a striking parallel with star formation, new structures suddenly appeared, together with a new level of complexity. Like stars, cities and states reorganize and energize the smaller objects within their gravitational field.

The urbanized,...

The era of agrarian civilizations has dominated conventional accounts of human history, partly because agrarian civilizations were the first human communities to generate the written records on which most modern historical research has been based. So we know this era in great detail. However, on the scale of big history, recounting a detailed description of this era is not appropriate. Besides, many fine histories already exist. Instead, this chapter will examine some of the large structures and trends that shaped the era of agrarian civilizations. Traditional approaches, which focus on particular civilizations or cultures, can easily hide these large trends....

In the past thousand years, and particularly in the past two or three hundred years, a transformation more rapid and more fundamental than any other in human history has taken place. A new threshold was crossed, leading to a fundamentally new type of society. Anthony Giddens writes, “Over a period of, at most, no more than three hundred years, the rapidity, drama and reach of change have been incomparably greater than any previous historical transitions. The social order . . . initiated by the advent of modernity is not just an accentuation of previous trends of development. In a number...

This chapter will survey world history in the period from 1000 CE to ca. 1700 CE, setting forth some of the changes that prepared the way for the Modern Revolution. It will concentrate first on global processes, showing how expansion in the size of exchange networks, slow before the sixteenth century and then much faster, created new possibilities both for the exchange of information and goods and for innovation. It will argue that the creation of a truly global exchange network in the sixteenth century decisively increased the scale, significance, and variety of informational and commercial exchanges. The coming together...

In the past 250 years, the Modern Revolution has transformed the world. Tables 13.1 and 13.2 and figure 13.1 offer some comparisons of industrial output over most of this era. And the first thing they suggest is that global industrial output has increased by almost 100 times. The figures are, of course, very rough-and-ready: the raw statistics are unreliable, as are definitions of “industrial potential,” and not all countries are included. Nevertheless, the general conclusions we can draw from these tables are very clear, and even significant adjustments to the details would not alter them.

On the scales of big...

The twentieth century is so close to us that we may think we understand it. But in some ways, it is harder to grasp than any other epoch discussed in this book. Of all periods of human history, the twentieth century may be the most difficult to see in the large perspective of big history. We cannot know what will stand out a few centuries into the future. In Eric Hobsbawm’s superb history of the “short” twentieth century,The Age of Extremes(1994), the things that loom large are the world wars of the first half of the century, the...

This book started out examining very large structures and huge timescales. But its focus has narrowed—first to a single planet, then to the history of a single species, and finally to a single century in the history of that species. Now we must move back up the temporal and spatial scales once more as we look toward the future.

We are all in a situation that resembles driving a fast vehicle at night over unknown terrain that is rough, full of gullies, with precipices not far off. Some kind of headlight, even a feeble and flickering one, may help...