Conscious

Exploring the Mystery of Consciousness

Annaka Harris

• Publisher: Harper
• Year: 2019
• ISBN:
  9780062906731
• Topic: Psicología
• Subtopic: Ciencia cognitiva

NEW YORK TIMES BESTSELLER

"If you've ever wondered how you have the capacity to wonder, some fascinating insights await you in these pages." --Adam Grant, New York Times bestselling author of Originals

As concise and enlightening as Seven Brief Lessons on Physics and Astrophysics for People in a Hurry, this mind-expanding dive into the mystery of consciousness is an illuminating meditation on the self, free will, and felt experience.

What is consciousness? How does it arise? And why does it exist? We take our experience of being in the world for granted. But the very existence of consciousness raises profound questions: Why would any collection of matter in the universe be conscious? How are we able to think about this? And why should we?

In this wonderfully accessible book, Annaka Harris guides us through the evolving definitions, philosophies, and scientific findings that probe our limited understanding of consciousness. Where does it reside, and what gives rise to it? Could it be an illusion, or a universal property of all matter? As we try to understand consciousness, we must grapple with how to define it and, in the age of artificial intelligence, who or what might possess it.

Conscious offers lively and challenging arguments that alter our ideas about consciousness—allowing us to thinkfreely aboutit for ourselves, if indeed we can.

1

Our experience of consciousness is so intrinsic to who we are, we rarely notice that something mysterious is going on. Consciousness is experience itself, and it is therefore easy to miss the profound question staring us in the face in each moment: Why would any collection of matter in the universe be conscious? We look right past the mystery as if the existence of consciousness were obvious or an inevitable result of complex life, but when we look more closely, we find that it is one of the strangest aspects of reality.

Thinking about consciousness can spark the same kind of pleasure we get from contemplating the nature of time or the origin of matter, invoking a deep curiosity about ourselves and the world around us. I remember looking up at the sky when I was young and realizing that my usual sense of being down on the ground with the sky above me wasn’t an entirely accurate perception. I was intrigued by the fact that even though I had learned that gravity pulls us toward the earth as we orbit the sun—and that there is no real “up” and “down”—my feeling of being down on the ground below the sky had remained unchanged. To shift my perspective, I would sometimes lie outside with my arms and legs outstretched and take in as much of the sky and horizon as possible. Attempting to break free of the familiar feeling of being down here with the moon and stars above me, I would relax all my muscles—surrendering to the force holding me tightly to the surface of our planet—and focus on the truth of my situation: I’m floating around the universe on this giant sphere—suspended here by gravity and going for a ride. Lying there, I could sense that I was in fact looking out at the sky, rather than up. The delight I experienced came from temporarily silencing a false intuition and glimpsing a deeper truth: being on the earth doesn’t separate us from the rest of the universe; indeed, we are and have always been in outer space.

This book is devoted to shaking up our everyday assumptions about the world we live in. Some facts are so important and so counterintuitive (matter is mostly made up of empty space; the earth is a spinning sphere in one of billions of solar systems in our galaxy; microscopic organisms cause disease; and so on) that we need to recall them again and again, until they finally permeate our culture and become the foundation for new thinking. The fundamental mysteriousness of consciousness, a subject deeply perplexing to philosophers and scientists alike, holds a special place among such facts. My goal in writing this book is to pass along the exhilaration that comes from discovering just how surprising consciousness is.

Before posing any questions about consciousness, we must determine what we are talking about in the first place. People use the word in a variety of ways; for example, in referring to a state of wakefulness, a sense of selfhood, or the capacity for self-reflection. But when we want to single out the mysterious quality at the heart of consciousness, it’s important to narrow in on what makes it unique. The most basic definition of consciousness is that given by the philosopher Thomas Nagel in his famous essay “What Is It Like to Be a Bat?,” and it is how I use the word throughout this book. The essence of Nagel’s explanation runs as follows:

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An organism is conscious if there is something that it is like to be that organism.¹

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In other words, consciousness is what we’re referring to when we talk about experience in its most basic form. Is it like something to be you in this moment? Presumably your answer is yes. Is it like something to be the chair you’re sitting on? Your answer will (most likely) be an equally definitive no. It’s this simple difference—whether there is an experience present or not—which we can all use as a reference point, that constitutes what I mean by the word “consciousness.” Is it like something to be a grain of sand, a bacterium, an oak tree, a worm, an ant, a mouse, a dog? At some point along the spectrum the answer is yes, and the great mystery lies in why the “lights turn on” for some collections of matter in the universe.

We can even wonder: At what point in the development of a human being does consciousness flicker into existence? Imagine a human blastocyst just a few days old, consisting of only about two hundred cells. We assume there is probably nothing it is like to be this microscopic collection of cells. But over time these cells multiply and slowly become a human baby with a human brain, able to detect changes in light and recognize its mother’s voice, even while in the womb. And, unlike a computer, which can also detect light and recognize voices, this processing is accompanied by an experience of light and sound. At whatever point in the development of a baby’s brain your intuition tells you, OK, now an experience is being had in there, the mystery lies in the transition. First, as far as consciousness is concerned, there is nothing, and then suddenly, magically, at just the right moment . . . something. However minimal that initial something is, experience apparently ignites in the inanimate world, materializing out of the darkness.

After all, an infant is composed of particles indistinguishable from those swirling around in the sun. The particles that compose your body were once the ingredients of countless stars in our universe’s past. They traveled for billions of years to land here—in this particular configuration that is you—and are now reading this book. Imagine following the life of these particles from their first appearance in space-time to the very moment they became arranged in such a way as to start experiencing something.

The philosopher Rebecca Goldstein paints a wonderfully clear and playful portrait of the mystery:

Sure, consciousness is a matter of matter—what else could it be, since that’s what we are—but still, the fact that some hunks of matter have an inner life . . . is unlike any other properties of matter we have yet encountered, much less accounted for. The laws of matter in motion can produce this, all this? Suddenly, matter wakes up and takes in the world?²

The moment matter becomes conscious seems at least as mysterious as the moment matter and energy sprang into existence in the first place. The mystery of consciousness rivals one of the greatest conundrums ever to bend human thought: How could something appear out of nothing?³ Likewise, how does felt experience arise out of nonsentient matter? The Australian philosopher David Chalmers famously termed this the “hard problem” of consciousness.⁴ Unlike the “easy problems” of explaining animal behavior or understanding which processes in the brain give rise to which functions, the hard problem lies in understanding why some of these physical processes have an experience associated with them at all.

Why do certain configurations of matter cause that matter to light up with awareness?

2

Now that we have a working definition of consciousness and the mystery it entails, we can start chipping away at some common intuitions. In large part, our intuitions have been shaped by natural selection to quickly provide lifesaving information, and these evolved intuitions can still serve us in modern life. For example, we have the ability to unconsciously perceive elements in our environment in threatening situations that in turn deliver an almost instantaneous assessment of danger—such as an intuition that we shouldn’t get into an elevator with someone, even though we can’t put our finger on why. Your brain is often processing helpful cues you may not be aware of in the moment: the other person who is getting into the elevator is flushed or has dilated pupils (both are signals that he is adrenalized and about to act violently), or the door to the building, which is usually locked, has been left ajar. We can know that a situation is dangerous without having any idea how or why we know it. Our intuitions are also shaped through learning, culture, and other environmental factors. We sometimes have useful intuitions about life decisions—such as which apartment to rent—born of relevant information that our brain has acquired, and taken into account, through unconscious processes. In fact, research suggests that our “gut feelings” are more reliable in many situations than the fruits of conscious reasoning.¹

But our gut can deceive us as well, and “false intuitions” can arise in any number of ways, especially in domains of understanding—such as science and philosophy—that evolution could never have foreseen. Consider probability and statistics, where our intuitions are notoriously unreliable: Many of us are nervous fliers, despite the fact that, statistically, we would need to fly every day for about 55,000 years before being involved in a fatal plane crash (and it’s worth mentioning that although people don’t commonly have panic attacks when getting behind the wheel in preparation for a trip to the grocery store, one’s safety on such trips is actually less secure by many orders of magnitude than while flying).² We can barely square our intuitions with some of the most basic scientific facts—the earth seemed flat to us until breakthroughs in celestial observations revealed otherwise. And in some areas of study, such as quantum physics, our intuitions are not only useless but are an outright obstacle to progress. An intuition is simply the powerful sense that something is true without our having an awareness or an understanding of the reasons behind this feeling—it may or may not represent something true about the world.

In this chapter, we will consider our intuitions regarding how we judge whether or not something is conscious, and we’ll discover that the seemingly obvious answers sometimes fall apart on closer inspection. I like to begin this exploration with two questions that at first glance appear deceptively simple to answer. Note the responses that first occur to you, and keep them in mind as we explore some typical intuitions and illusions.

1. In a system that we know has conscious experiences—the human brain—what evidence of consciousness can we detect from the outside?
2. Is consciousness essential to our behavior?

These two questions overlap in important ways, but it’s informative to address them separately. Consider first that it’s possible for conscious experience to exist without any outward expression at all (at least in a brain). A striking example of this is the neurological condition called locked-in syndrome, in which virtually one’s entire body is paralyzed but consciousness is fully intact. This condition was made famous by Jean-Dominique Bauby, the late editor in chief of French Elle, who ingeniously devised a way to write about his personal story of being “locked in.” After a stroke left him paralyzed, Bauby retained only the ability to blink his left eye. Amazingly, his caretakers noticed his efforts to communicate, and over time they developed a method whereby he could spell out words through a pattern of blinks, thus revealing the full scope of his conscious life. He describes this harrowing experience in his 1997 memoir, The Diving Bell and the Butterfly, which he wrote in about two hundred thousand blinks. Of course, we may assume that his consciousness would not have been changed whatsoever if his left eyelid had succumbed to the paralysis as well. And without this mobility, there would have been absolutely no way for him to communicate that he was fully conscious.

Another example of bodily imprisonment is a condition called “anesthesia awareness,” in which a patient given a general anesthetic for a surgical procedure experiences only the paralysis without losing consciousness. People in this condition must live out the nightmare of feeling every aspect of a medical procedure, sometimes as drastic as the removal of an organ, without the ability to move or communicate that they are fully awake and experiencing pain. This and the previous example seem to come straight out of a horror movie, but we can imagine other, less disturbing instances in which a conscious mind might lack a mode of expression—scenarios involving artificial intelligence (AI), for example, in which an advanced system becomes conscious but has no way of convincingly communicating this to us. But one thing is certain: it’s possible for a vivid experience of consciousness to exist undetected from the outside.

Now let’s go back to the first question and ask ourselves: What might qualify as evidence of consciousness? For the most part, we believe we can determine whether or not an organism is conscious by examining its behavior. Here is a simple assumption most of us make, in line with our intuitions, that we can use as a starting point: “People are conscious; plants are not conscious.” Most of us feel strongly that this statement is correct, and there are good scientific reasons for believing that it is. We assume that consciousness does not exist in the absence of a brain or a central nervous system. But what evidence or behavior can we observe to support this claim about the relative experience of human beings and plants? Consider the types of behavior we usually attribute to conscious life, such as reacting to physical harm or caring for others. Research reveals that plants do both of these things in complex ways—though, of course, we conclude that they do so without feeling pain or love (i.e., without consciousness). But some behaviors of people and plants are so alike that this in fact poses a challenge to our using certain behavior as evidence of conscious experience.

In his book, What a Plant Knows: A Field Guide to the Senses, Daniel Chamovitz describes in fascinating detail how the stimulation of a plant (by touch, light, heat, etc.) can cause reactions similar to those in animals under analogous conditions. Plants can sense their environment through touch and can detect many aspects of their surroundings, including temperature, by other modes. It’s actually quite common for plants to react to touch: a vine will increase its rate and change ...