The Big Picture
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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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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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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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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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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