person put a Big Bird doll inside one of two boxes in front of him. Then that
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person leaves the room, and another one comes in and switches Big Bird
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from the first box to the second one. The second person leaves and the first
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returns. Leonardo is smart enough to know both that Big Bird is in the
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second box, and that the first person “believes” that it’s in the first box.
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The experimenter then asks, “Leo, can you find where I think Big Bird
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is?” This is a query about metacognition, thinking about thinking. Leon-
35S
ardo correctly points to the first box, corresponding to his model of the
36N
experimenter’s beliefs. But while pointing at the first box, Leonardo also
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sneaks a quick glance at the second box, where Big Bird is actually located.
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This wasn’t programmed behavior; it was something that the robot learned
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from interacting with humans.
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Whether you are a fish crawling onto land, a robot dealing with experi-
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menters in the lab, or a person interacting with other people, it is helpful to
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have models of the world around you, including other organisms and their
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models. Awareness of ourselves and others, and the ability to communicate
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and interact on a number of levels, are useful capacities to have as we work
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to survive in a complicated world.
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01
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The Hard Problem
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life on Earth has undergone a series of dramatic phase transitions.
Self- replicating organisms, cell nuclei, multicellular life, climbing
onto land, the origin of language— all of these represent important
new capacities that changed what life was capable of. The appearance of
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consciousness is arguably the most interesting phase transition of all, the
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beginning of a new kind of way for matter to organize itself and behave.
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Not only can atoms organize themselves into complex, self- sustaining pat-
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terns, but those patterns acquire a capacity for self- awareness and the ability
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to think about their place in the cosmos.
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Unless something much deeper is going on. As philosopher Thomas Na-
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gel has put it, “The existence of consciousness seems to imply that . . . the
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natural order is far less austere than it would be if physics and chemistry
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accounted for everything.” (It was Nagel who really emphasized that “what
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it is like” to feel something is the kind of thing a complete theory should be
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able to explain. His famous example was that we can’t know what it is like
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to be a bat, but the point is more general.) On this view, we shouldn’t hope
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to explain conscious experience purely in terms of the physical behavior of
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the quantum fields in the Core Theory, since consciousness transcends the
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physical world.
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It’s not hard to understand why someone might feel this way. Fine, the
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thinking goes, I can accept that the universe exists and obeys natural laws
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without appealing to anything outside. I have no trouble believing that life
36N
is a complex network of interlocking chemical reactions that began
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spontaneously and evolved through natural selection over billions of years.
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But surely I am more than just a bunch of atoms knocking into one another
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under the influence of gravity and electromagnetism. I perceive, I feel—
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there is something that it is like to be me, something uniquely personal and
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experiential, a rich inner life that can’t possibly be accounted for by un-
05
thinking matter in motion, no matter how many atoms you congregate
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together. The issue has been dubbed the mind- body problem: how can we
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hope to account for mental reality using only physical concepts?
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As with the origin of life and the origin of the universe, we can’t claim
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to have a full understanding of the nature of consciousness. The study of
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how we think and feel, not to mention how to think about who we are, is
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in its relative infancy. As neuroscientist and philosopher Patricia Church-
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land has put it, “We’re pre- Newton, pre- Kepler. We’re still sussing out that
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there are moons around Jupiter.”
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But nothing we do know about consciousness should lead us to doubt
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the ordinary, naturalist conception of the world that has been so exception-
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ally successful in other contexts. As of right now, nothing about the mind-
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body problem should persuade us that the laws of physics need updating,
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amending, or augmenting.
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20
•
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Like “life,” consciousness is less a unified conception and more a collection
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of related attributes and phenomena. We are aware of ourselves, as distinct
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from the outside world. We can contemplate alternative futures. We experi-
24
ence sensations. We can reason abstractly and symbolically. We feel emo-
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tions. We can call up memories, tell stories, and sometimes lie. The
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simultaneous working of all these aspects contributes to being conscious,
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and some aspects are going to be easier to explain in purely physical terms
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than others.
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Consider the color red.
It is a useful concept, one that can apparently be
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recognized universally and objectively, at least by sighted people who are
31
not prevented from seeing red by color blindness. The operational instruc-
32
tion “stop when the light is red” can be understood without ambiguity. But
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there is the famous lurking question: do you and I see the same thing when
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we see something red? That’s the question of phenomenal consciousness—
S35
what is it like to experience redness?
N36
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The word qualia (plural of “quale,” which is pronounced KWAH- lay) is
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sometimes used to denote the subjective experience of the way something
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seems to us. “Red” is a color, a physically objective wavelength of light or
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appropriate combination thereof; but “the experience of the redness of red”
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is one of the qualia we would like to account for in a complete understand-
06
ing of consciousness.
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Australian philosopher David Chalmers has famously emphasized the
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difference between what he calls the Easy Problems and the Hard Problem
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of consciousness. The Easy Problems are manifold— explaining the differ-
10
ence between being awake and asleep, how we sense and store and integrate
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information, how we can recall the past and predict the future. The Hard
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Problem is explaining qualia, the subjective character of experience. It can
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be thought of as those aspects of consciousness that are irreducibly first-
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person; what we personally feel, not how we act and respond as seen by the
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rest of the world. The Easy Problems are about functioning; the Hard Prob-
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lem is about experiencing.
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It’s the Hard Problem that poses an apparent challenge to a purely phys-
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ical understanding of the world. The Easy Problems aren’t easy, but they are
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squarely in the wheelhouse of conventional scientific investigation. We
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don’t have a finished understanding of how photons impinging on our
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retinas while we are looking at a fish end up conjuring the notion of “fish”
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in our brains. But the path to getting there seems pretty neuroscientifically
23
straightforward. The Hard Problem, by contrast, seems like an entirely dif-
24
ferent kettle of those fish. We can poke around in the brain all we like, but
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how in the world do we expect that to help us understand our inner, wholly
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subjective, experience? How can a collection of quantum fields evolving in
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accordance with the Core Theory be said to have “inner experience” at all?
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Many experts on consciousness think of these two issues, in the words
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of Peter Hankins, as “the Easy Problem (which is hard), and the Hard Prob-
30
lem (which is impossible).” But some think the Hard Problem is not only
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pretty easy; it really isn’t a problem at all— just a matter of conceptual con-
32
fusion. Discussions between the two camps can be frustrating; there’s noth-
33
ing more disheartening than someone telling you that the problem you
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think is most important and central isn’t really a problem at all.
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As poetic naturalists, that’s basically what we’ll be doing. The attri-
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butes of consciousness, including our qualia and inner subjective
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experiences, are useful ways of talking about the effective behavior of the
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collections of atoms we call human beings. Consciousness isn’t an illusion,
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but it doesn’t point to any departure from the laws of physics as we cur-
03
rently understand them.
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05
•
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There are a number of thought experiments that try to illustrate how hard
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the Hard Problem really is. A famous one is Mary the Color Scientist, a
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colorful (as it were) instantiation of what’s known as the knowledge argu-
09
ment. It was introduced by Australian philosopher Frank Jackson in the
10
1980s, with the goal of showing that there must be something in the world
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other than just physical facts. It’s right up there with Searle’s Chinese Room
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on the list of famous thought experiments in which philosophers lock peo-
13
ple into strange rooms in order to illustrate some feature of consciousness.
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Mary is a brilliant scientist who has been brought up under certain bi-
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zarre circumstances. She lives in a room that she has never left, and that
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room is completely devoid of color. Everything in the room is black, white,
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or some shade of gray. Her own skin is painted white, and all of her clothes
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are black. Curiously, given her environment, Mary grows up to become a
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specialist in the science of color. She has access to all of the equipment she
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would want, as well as to the entirety of the scientific literature on the sub-
21
ject of color. All of the color illustrations have been reduced to grayscale.
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Eventually, Mary knows everything there is to know about color, from
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a physical point of view. She knows about the physics of light, and about the
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neuroscience of how the eye transmits signals to the brain. She’s read up on
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art history, color theory, and the agricultural expertise involved in growing
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a perfect red tomato. She’s just never seen the color red.
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Jackson asks, what happens when Mary decides to leave her room and
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actually sees colors for the first time? In particular, does she learn anything 29
new? He claims she does.
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What will happen when Mary is released from her black and
32
white room or is given a color television monitor? Will she learn
33
anything or not? It seems just obvious that she will learn some-
34
thing about the world and our visual experience of it. But then
S35
is it inescapable that her previous knowledge was incomplete.
N36
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T H E B IG PIC T U R E
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But she had all the physical information. Ergo there is more to
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have than that, and Physicalism is false.
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Mary can know all of the physical facts about color, but there is still
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something she doesn’t know: “what it is like” to experience the color red.
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Therefore, there are more kinds of things in the world than merely physical
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things. The argument is not merely saying that we don’t yet know how
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to explain Mary’s new experience in physical terms. The claim is that no
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such explanation can possibly exist.
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Like the Chinese Room, Mary’s predicament relies on a thought-
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experiment setup that sounds relatively innocent, but is wildly implausible
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in practice. “All of the physical facts about color” is an awful lot of facts.
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Here is a physical fact about color: when I cut my finger while chopping
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onions last week, my blood was red. Does Mary know that I cut my finger
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while chopping onions last week? Does she know the position and momen-
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tum and frequency of every photon of visible light in the whole universe?
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What about the past and future of the universe? Like “an omniscient, om-
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nipotent, and omnibenevolent being,” the phrase “all the physical facts
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about color” conjures a certain vague impression in our minds, but it’s far
20
from clear that this expression corresponds to any well- defined concept.
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•
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Vagueness about physical facts isn’t the biggest problem with citing Mary
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as evidence for the existence of features of the universe that aren’t purely
25
physical. The real issue is with slipperiness in the definitions of “knowl-
26
edge” and “experience.”
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Let’s consider Mary’s predicament from a poetic- naturalism perspective.
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There is some fundamental description of our world, in terms of an evolv-
29
ing quantum wave function or perhaps something deeper. The other con-
30
cepts we appeal to, such as “rooms” and “red,” are part of vocabularies that
31
provide useful approximate models for certain aspects of that underlying
32
reality in an appropriate domain of applicability. So we invent, for example,
33
the concept of a “person,” which maps onto the underlying reality in a par-
34
ticular way— a way that might be difficult to precisely define in principle
35S
but is easy to recognize in practice.
The Big Picture Page 59