The Big Picture

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The Big Picture Page 2

by Carroll, Sean M.


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  any laws of nature to imagine living beings lasting for millions or even bil-

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  lions of years, so I have no objection there. But eventually all of the stars

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  will have exhausted their nuclear fuel, their cold remnants will fall into

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  black holes, and those black holes will gradually evaporate into a thin gruel

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  of elementary particles in a dark and empty universe. We won’t really live

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  forever, no matter how clever biologists get to be.

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  Everybody dies. Life is not a substance, like water or rock; it’s a process,

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  like fire or a wave crashing on the shore. It’s a process that begins, lasts for

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  a while, and ultimately ends. Long or short, our moments are brief against

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  the expanse of eternity.

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  PR O l O g u E

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  We have two goals in front of us. One is to explain the story of our universe

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  and why we think it’s true, the big picture as we currently understand it. It’s

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  a fantastic conception. We humans are blobs of organized mud, which

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  through the impersonal workings of nature’s patterns have developed the

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  capacity to contemplate and cherish and engage with the intimidating com-

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  plexity of the world around us. To understand ourselves, we have to under-

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  stand the stuff out of which we are made, which means we have to dig deeply

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  into the realm of particles and forces and quantum phenomena, not to men-

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  tion the spectacular variety of ways that those microscopic pieces can come

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  together to form organized systems capable of feeling and thought.

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  The other goal is to offer a bit of existential therapy. I want to argue that,

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  though we are part of a universe that runs according to impersonal underly-

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  ing laws, we nevertheless matter. This isn’t a scientific question— there isn’t 15

  data we can collect by doing experiments that could possibly measure the

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  extent to which a life matters. It’s at heart a philosophical problem, one that

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  demands that we discard the way that we’ve been thinking about our lives

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  and their meaning for thousands of years. By the old way of thinking, hu-

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  man life couldn’t possibly be meaningful if we are “just” collections of at-

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  oms moving around in accordance with the laws of physics. That’s exactly

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  what we are, but it’s not the only way of thinking about what we are. We are

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  collections of atoms, operating independently of any immaterial spirits or

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  influences, and we are thinking and feeling people who bring meaning into

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  existence by the way we live our lives.

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  We are small; the universe is big. It doesn’t come with an instruction

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  manual. We have nevertheless figured out an amazing amount about how

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  things actually work. It’s a different kind of challenge to accept the world

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  for what it is, to face reality with a smile, and to make our lives into some-

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  thing valuable.

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  In the first section of the book, “Cosmos,” we examine some important

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  aspects of the wider universe of which we are a small part. There are many

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  ways to talk about the world, which leads us to the framework called poetic

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  naturalism. “Naturalism” claims that there is just one world, the natural

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  T H E B IG PIC T U R E

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  world; we’ll explore some of the indications that point us in that direction,

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  including how the universe moves and evolves. “Poetic” reminds us that

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  there is more than one way of talking about the world. We find it natural

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  to use a vocabulary of “causes” and “reasons why” things happen, but those

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  ideas aren’t part of how nature works at its deepest levels. They are emergent

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  phenomena, part of how we describe our everyday world. The difference

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  between the everyday and deeper descriptions arises from the arrow of

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  time, the distinction between past and future that can ultimately be traced

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  to the special state in which our universe began near the Big Bang.

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  In the second section, “Understanding,” we consider how we should go

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  about trying to understand the world. Or, at least, move closer and closer to

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  the truth; we have to be willing to accept uncertainty and incomplete knowl-

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  edge, and always be ready to update our beliefs as new evidence comes in. We

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  will see how our best approach to describing the universe is not a single,

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  unified story but an interconnected series of models appropriate at different

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  levels. Each model has a domain in which it is applicable, and the ideas that

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  appear as essential parts of each story have every right to be thought of as

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  “real.” Our task is to assemble an interlocking set of descriptions, based on

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  some fundamental ideas, that fit together to form a stable planet of belief.

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  We then turn to “Essence,” where we think about the world as it actu-

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  ally is: the fundamental laws of nature. We’ll discuss quantum field theory,

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  the basic language in which modern physics is written. We will appreciate

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  the triumph of the Core Theory, the enormously successful model of the

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  particles and forces that make up you, me, the sun, the moon, the stars, and

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  everything you have ever seen, touched, or tasted in all your life. There is

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  much we don’t know about how the world works, but we have extremely

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  good reason to think that the Core Theory is the correct description of

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  nature in its domain of applicability. That domain is wide enough to im-

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  mediately exclude a number of provocative phenomena: from telekinesis

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  and astrology to survival of the soul after death.

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  With some laws of physics in hand, there is still much work to be done

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  in connecting these deeper principles to the richness of the world around

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  us. In the fourth section, “Complexity,” we begin to see how those connec-<
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  tions come about. The emergence of complex structures isn’t a strange phe-

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  nomenon in tension with the general tendency of the universe toward

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  greater disorder; it is a natural consequence of that tendency. In the right

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  PR O l O g u E

  circumstances, matter self- organizes into intricate configurations, capable

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  of capturing and using information from their environments. The culmina-

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  tion of this process is life itself. The more we learn about the basic workings

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  of life, the more we appreciate how they are in harmony with the funda-

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  mental physical principles governing the universe as a whole. Life is a pro-

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  cess, not a substance, and it is necessarily temporary. We are not the reason

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  for the existence of the universe, but our ability for self- awareness and re-

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  flection makes us special within it.

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  This brings us to one of the knottier problems faced by naturalism, the

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  puzzle of consciousness. We confront this issue in “Thinking,” where we go

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  beyond “naturalism” all the way to “physicalism.” Modern neuroscience has

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  made tremendous strides in understanding how thought actually works

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  inside our brains, and there is little question that our personal experiences

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  have definite correlates in physical processes therein. We can even begin to

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  see how this remarkable ability evolved over time, and what kinds of abili-

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  ties are crucial to achieving consciousness. The most difficult problem is a

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  philosophical one: how is it even possible that inner experience, the

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  uniquely experiential aboutness of our lives inside our heads, can be reduced

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  to mere matter in motion? Poetic naturalism suggests that we should think

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  of “inner experiences” as part of a way of talking about what is happening

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  in our brains. But ways of talking can be very real, even when it comes to

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  our ability to make free choices as rational beings.

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  Finally, in “Caring” we confront the hardest problem of all, that of how

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  to construct meaning and values in a cosmos without transcendent pur-

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  pose. A common charge against naturalism is that such a task is simply

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  impossible: without something beyond the physical world to guide us, there

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  is no reason to live at all, and certainly no reason to live one way rather than

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  another. Some naturalists respond by agreeing, and getting on with their

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  lives; others react strongly the other way, by arguing that values can be de-

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  termined scientifically just as much as the age of the universe can be. Poetic

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  naturalism strikes a middle ground, accepting that values are human con-

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  structs, but denying that they are therefore illusory or meaningless. All of

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  us have cares and desires, whether given to us by evolution, our upbringing,

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  or our environment. The task before us is to reconcile those cares and de-

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  sires within ourselves, and amongst one another. The meaning we find in

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  life is not transcendent, but it’s no less meaningful for that.

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  P A R t O n E

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  COSMOS

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  The Fundamental Nature of Reality

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  I

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  n the old Road Runner cartoons, Wile E. Coyote would frequently

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  find himself running off the edge of a cliff. But he wouldn’t, as our

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  experience with gravity might lead us to expect, start falling to the

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  ground below, at least not right away. Instead, he would hover motionless,

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  in puzzlement; it was only when he realized there was no longer any ground

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  beneath him that he would suddenly crash downward.

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  We are all Wile E. Coyote. Since human beings began thinking about

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  things, we have contemplated our place in the universe, the reason why we

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  are all here. Many possible answers have been put forward, and partisans of

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  one view or another have occasionally disagreed with each other. But for a

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  long time, there has been a shared view that there is some meaning, out

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  there somewhere, waiting to be discovered and acknowledged. There is a

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  point to all this; things happen for a reason. This conviction has served as

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  the ground beneath our feet, as the foundation on which we’ve constructed

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  all the principles by which we live our lives.

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  Gradually, our confidence in this view has begun to erode. As we under-

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  stand the world better, the idea that it has a transcendent purpose seems

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  increasingly untenable. The old picture has been replaced by a wondrous

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  new one— one that is breathtaking and exhilarating in many ways, chal-

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  lenging and vexing in others. It is a view in which the world stubbornly

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  refuses to give us any direct answers about the bigger questions of purpose

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  and meaning.

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  The problem is that we haven’t quite admitted to ourselves that this

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  T H E B IG PIC T U R E

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  transition has taken place, nor fully accepted its far- reaching implications.

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<
br />   The issues are well-known. Over the course of the last two centuries, Dar-

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  win has upended our view of life, Nietzsche’s madman bemoaned the death

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  of God, existentialists have searched for authenticity in the face of absur-

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  dity, and modern atheists have been granted a seat at society’s table. And

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  yet, many continue on as if nothing has changed; others revel in the new

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  order, but placidly believe that adjusting our perspective is just a matter of

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  replacing a few old homilies with a few new ones.

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  The truth is that the ground has disappeared beneath us, and we are just

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  beginning to work up the courage to look down. Fortunately, not every-

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  thing in the air immediately plummets to its death. Wile E. Coyote would

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  have been fine if he had been equipped with one of those ACME- brand jet

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  packs, so that he could fly around under his own volition. It’s time to get to

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  work building our conceptual jet packs.

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  What is the fundamental nature of reality? Philosophers call this the

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  question of ontology— the study of the basic structure of the world, the in-

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  gredients and relationships of which the universe is ultimately composed.

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  It can be contrasted with epistemology, which is how we obtain knowledge

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  about the world. Ontology is the branch of philosophy concerned with the

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  nature of reality; we also talk about “an” ontology, referring to a specific

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  idea about what that nature actually is.

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  The number of approaches to ontology alive in the world today is some-

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  what overwhelming. There is the basic question of whether reality exists at

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  all. A realist says, “Of course it does”; but there are also idealists, who think 25

  that capital- M Mind is all that truly exists, and the so-called real world is

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  just a series of thoughts inside that Mind. Among realists, we have monists,

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  who think that the world is a single thing, and dualists, who believe in two

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  distinct realms (such as “matter” and “spirit”). Even people who agree that

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  there is only one type of thing might disagree about whether there are fun-

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  damentally different kinds of properties (such as mental properties and

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  physical properties) that those things can have. And even people who agree

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  that there is only one kind of thing, and that the world is purely physical,

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  might diverge when it comes to asking which aspects of that world are

 

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