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Book Summary: The Upright Thinkers

Author: Leonard Mlodinow

Substory: What Makes Humans Special: We Shape The Environment Around Us

Those of us who look in the mirror each morning see something that few other animals ever recognize: ourselves. Some of us smile at our image and blow ourselves a kiss; others rush to cover the disaster with makeup or to shave, lest we appear unkempt. Either way, as animals go, the human reaction is an odd one. We have it because somewhere along the path of evolution we humans became self-aware. Even more important, we began to have a clear understanding that the face we see in reflections will in time grow wrinkles, sprout hair in embarrassing places, and, worst of all, cease to exist. That is, we had our first intimations of mortality.

Our brain is our mental hardware, and it was for purposes of survival that we developed one with the capacity to think symbolically and to question and reason. But hardware, once you have it, can be put to many uses, and as our Homo sapiens sapiens imagination leapt forward, the realization that we will all die helped turn our brains toward existential questions such as “Who is in charge of the cosmos?” This is not a scientific question per se, yet the road to questions like “What is an atom?” began with such queries, as well as more personal ones, like “Who am I?” and “Can I alter my environment to suit me?” It is when we humans rose above our animal origins and began to make these inquiries that we took our next step forward as a species whose trademark is to think and question.

The change in human thought processes that led us to consider these issues probably simmered for tens of thousands of years, beginning around the time—probably forty thousand years ago or thereabouts—when our subspecies began to manifest what we think of as modern behaviors. But it didn’t boil over until about twelve thousand years ago, around the end of the last ice age. Scientists call the two million years leading up to that period the Paleolithic era, and the following seven or eight thousand years the Neolithic era. The names come from the Greek words palaio, meaning “old,” neo, meaning “new,” and lithos, meaning “stone”—in other words, the Old Stone Age (Paleolithic) and the New Stone Age (Neolithic), both of which were characterized by the use of stone tools. Though we call the sweeping change that took us from the Old to the New Stone Age the “Neolithic revolution,” it wasn’t about stone tools. It was about the way we think, the questions we ask, and the issues of existence that we consider important.

Paleolithic humans migrated often, and, like my teenagers, they followed the food. The women gathered plants, seeds, and eggs, while the men generally hunted and scavenged. These nomads moved seasonally—or even daily—keeping few possessions, chasing the flow of nature’s bounty, enduring her hardships, and living always at her mercy. Even so, the abundance of the land was sufficient to support only about one person per square mile, so for most of the Paleolithic era, people lived in small wandering groups, usually numbering fewer than a hundred individuals. The term “Neolithic revolution” was coined in the 1920s to describe the transition from that lifestyle to a new existence in which humans began to settle into small villages consisting of one or two dozen dwellings, and to shift from gathering food to producing it.

With that shift came a movement toward actively shaping the environment rather than merely reacting to it. Instead of simply living off the bounty nature laid before them, the people living in these small settlements now collected materials with no intrinsic worth in their raw form and remade them into items of value. For example, they built homes from wood, mud brick, and stone; forged tools from naturally occurring metallic copper; wove twigs into baskets; twisted fibers gleaned from flax and other plants and animals into threads and then wove those threads into clothing that was lighter, more porous, and more easily cleaned than the animal hides people had formerly worn; and formed and fired clay into pots and pitchers that could be used for cooking or storing surplus food products.

At face value, the invention of objects like clay pitchers seems to represent nothing deeper than the realization that it is hard to carry water around in your pocket. And indeed, until recently many archaeologists thought that the Neolithic revolution was merely an adaptation aimed at making life easier. Climate change at the end of the last ice age, ten to twelve thousand years ago, resulted in the extinction of many large animals and altered the migration patterns of others. This, it was assumed, had put pressure on the human food supply. Some also speculated that the number of humans had finally grown to the point that hunting and gathering could no longer support the population. Settled life and the development of complex tools and other implements were, in this view, a reaction to these circumstances.