A Short History of Evolution: Deconstructing the Promethean Spark (Part 1)

This article is part of Carl Coon’s ongoing “A Short History of Evolution” series. Click here to read all entries in this series.

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About 50,000 years ago a group of people that looked like us burst out of Africa and quickly overran a great deal of Eurasia, including Southeast Asia and Australia as well as Europe. The earlier populations of more primitive humans, as far as we can tell, disappeared. What was it that made the difference, that so distinguished our sapient ancestors when they burst out of Africa that they spread all over the world? The Greeks attributed it to a gift from the gods, with Prometheus giving humankind fire. Can science give us a better answer?  

Introducing Intentionality

H. Sapiens is the first (and so far the only) species that has exploited the quality of intentionality. What is intentionality? How should we define it? Some scientists use the term "theory of the mind" for a similar concept. For present purposes let's agree to take both terms as including a capacity to imagine things or happenings that do not presently exist in the environment, but that could be beneficial, and make them happen.  Likewise, intentionality implies a capacity to envision conditions or situations which would be harmful, even when they do not (yet) exist--and take steps to avoid them, or at least moderate their impact when they do happen. Why do we bother to distinguish between intentionality and intelligence?  Why not consider our acquisition of intentionality as just another stage in the evolution of intelligence, rather than a game changer? Here's a common sense answer: many life forms exhibit some level of intelligence, but if any animal other than man had been able to acquire intentionality as we've just defined it, we'd know about it, assuming we were even around to care. There's another answer that’s more central to the present discussion. There may well be a broad analogy here, and a significant one, with the distinction we drew between single-celled organisms that reproduce by splitting and their vastly more versatile successors that evolved when a few of them developed detailed copying via sexual reproduction. The successors succeeded because they could produce a much larger number of variations in each generation, which greatly increased the rate at which natural selection took place. A supercharged selective process took off, leading eventually to the diverse life forms that now dominate our planet. Likewise, intentionality changes the way the whole system works. It breaks the iron straitjacket of natural selection that enables change but only via selection from one generation to another. Creatures of the human mind can be conceived, made, revised over and over again, and replaced, all in the space of a single human lifespan (although some ideas, like religion, may live much longer). They are not alive, at least as we define life, though they can pass through many of the same stages as living things. We need to keep this distinction in mind when we think about how these creatures of the human mind change and evolve over time.  

What Is Intentionality? 

The human brain consists of upwards of 100 billion neurons that interact with each other as they click on and off, forming a myriad of patterns that collectively constitute what we think of as thought. Think of the brain as a gas oven. When it sleeps only the pilot light stays on, but when it's activated many jets produce an array of flames. The flames themselves are insubstantial, as is our thought. It is the patterns that count. Thinking of thinking in this way lets us conceptualize the human brain as something that evolved from a more primitive organ that had fewer neurons to work away at pattern creation. This tracks well with the archeological evidence that our ancestral cousins had smaller brain cases, and that there was a gradual increase in cranial capacity that broadly correlates with other archeological evidence for human evolution. Thinking of thinking in this way also helps us to manage the perhaps insoluble problems of the mind-brain relationship and human consciousness, in that we can view the thought process as observers rather than participants. We can avoid the subjective tangles we get into when we try to compare that many-splendored thing, intelligence, both between individuals and between groups. This narrative, after all, is about evolution, not how smart we are. It is enough for our purposes to say that as a species we are a lot smarter, more adaptable, and more versatile than any other species on our planet.  

On Tipping Points and How We Got Past Them

It is a basic premise of this narrative that things don’t just happen; they evolve out of other things. They evolve out of a winnowing process that is governed both by the nature of the environment and by variations in their own structure. We call this process natural selection when the subjects are living things, including ourselves. As with the origin of life itself, we will probably never be able to point to a specific event and declare that that is when we first became human. Too many different things were happening in too many places and times. But we can define a broad period and a geographic region within which we passed what might be called our critical tipping point, and examine both the environmental circumstances and other factors for clues about what happened. We are talking about a period covering roughly the first half of the last hundred thousand years. Neither the environmental circumstances nor the archeological evidence for that period is as well-known or understood compared to what we know about more recent periods. We are reasonably certain, however, that periodic climate changes were important in forcing the evolutionary pace. We’ll cover this in Chapter IV. Intentionality didn’t just evolve by itself. It was enabled, one might almost say begotten, by two other evolutionary tracks that operated symbiotically and synergistically to produce the kind of proactive intelligence we call intentionality. Those two factors are language and altruism. We shall consider them in the next couple of issues.

This article is part of Carl Coon’s ongoing “A Short History of Evolution” series. Click here to read all entries in this series.