Time Reborn: From the Crisis in Physics to the Future of the Universe
by Lee Smolin
First Reviewed May 2013
Dang, dude, my reviews were way too long. How badly did I want to be writing for The New Yorker? 2500 words is way too many., especially if half of them are block quotes. Also, 11 years ago? Yikes. I remember nothing from this book, not even why I started it. I think that was my point, to both practice writing and remind myself of the things I’ve read years later. But who wants to read this review? No one, according to the metrics—not even me.
Also, if I hated bad subtitles so much, why did I keep reading books that employed them? I am pretty sure I just wandered around the basement of The Strand, noting whatever was new and then requesting them from the library.
Tossing off the word “crisis” is enough of a signifier to fulfill the burden of “shocking-subtitle” that most non-fiction carries. The remainder of the subtitle in Time Reborn: From the Crisis in Physics to the Future of the Universe has the potential to be more egregiously hyperbolic but for the fact that most readers are unlikely to be current on the cosmological scuttlebutt. A theoretical physicist or cosmologist would not be having a first encounter these theories in a pop-sci book, so their actual knowledge of a crisis in physics is wasted. Time Reborn is for the layperson, so the subtitle has the air of a marketing catchphrase rather than an impactful phrasing of what is to come. Though, in the case of a short generic like Time Reborn, distinguishment—not significance—may be the goal.
Those burdened by the metaphysical presupposition that the purpose of science is to discover timeless truths represented by timeless mathematical objects might think that eliminating time and so making the universe akin to a mathematical object is a route to scientific cosmology. But it turns out to be the opposite.
The bulk of Time Reborn is a refresher course in physics so that the reader has the basic knowledge to understand how little time figures into modern theoretical physics. In fact, it is actively excluded. To put it back, you need to know—well, everything.
Mathematics entered science as an expression of a belief in the timeless perfection of the heavens. Useful as mathematics has turned out to be, the postulation of timeless mathematical laws is never completely innocent, for it always carries a trace of the metaphysical fantasy of transcendence from our earthly world to one of perfect forms.
What happens is the reader—the one that can be counted on as having almost no basic theoretical understanding—is walked through two thousand years of math and physics and is spit out on the other side completely ready to accept whatever current cosmological theory to which <u>Time Reborn</u> has spent the last 200 pages building. Within the framework of the history presented, the conclusions seems inevitable; it would take a reader that brings in far more outside information than I to feel confident in proclaiming how strong these modern theories of fundamental time are.
What Time Reborn does well is take a dense subject and inject interesting writing and clear vignettes to make physics unintimidating. Not once does the author talk down to the reader, nor needless complicate the subject in an attempt to academia-up the book. The fast-paced historical journey leads right up to the “crisis in physics” to which the seemingly alarmist—but wholly accurate—subtitle refers:
Most of what we know about nature has come from experiments in which we artificially mark off and isolate a phenomenon from the continual whirl of the universe....What Descartes, Galileo, Kepler, and Newton learned to do was to isolate little pieces of the world, examine them, and record the changes in them. They showed us how to display the records of these motions in simple diagrams whose axes represent the positions and times in a way that is frozen and hence amenable to being studied at our leisure.
In much the same way that social variables and personal intangibles have been diminished to fit within a mathematical equation that is computationally friendly, time has been scrubbed out of physics and math so that equations will function. They are approximations of the world, not definites, analogous to the way that the websites you click on are not you the person; within the framework of marketing engines, your clicks are how algorithms interpret—and corporations envision—you. You are become an equation built from tiny fractions of information, smashed together to provide workable—though woefully incomplete—data:
The notion of effective theories subverts some well-worn notions, such as the platitude that simplicity and beauty are hallmarks of truth. Since we don’t know what could be lurking at higher energies, many hypotheses of physics beyond its specified domain are consistent with one or another effective theory. So these effective theories have an intrinsic simplicity, because they have to be consistent with the simplest and most elegant way they could be extended into unknown domains. A large part of the elegance of general relativity and the Standard model is explained by understanding them as effective theories. Their beauty is a consequence of their being effective and approximate. Simplicity and beauty, then, are signs not of truth but of a well-constructed approximate model of a limited domain of phenomena.
Your facebook page—with its photos and multiple-choice dropdown boxes and “It’s Complicated” relationship status—is the simple version of you; the “math” version that computer algorithms can work with to increase their effective marketing. It isn’t really you, just a “well-constructed approximate model of limited domain<”. So is there an offline, real world version of physics that cannot be scaled up from the pageclick-esque data our mathematical formulae currently capture? Time Reborn drops this problem onto the head of quantum mechanics:
Quantum mechanics is not a theory so much as a method for coding how experimenters interrogate microscopic systems. Neither the measuring instruments we use to interact with a quantum system nor the clock we use to measure time can be described in the language of quantum mechanics—nor can we, as observers, be so described. This suggest that to make a valid cosmological theory we will have to give up quantum mechanics and replace it with a theory that can be extended to the whole universe, including ourselves as observers and our measuring instruments and clocks.
You cannot approximate a person en totale simply by extrapolating scraped data, and you cannot extend quantum mechanics from the micro to the macro, let alone to the cosmological.
Seriously. If you only had information about what someone does online, and absolutely no prior experience or knowledge of what a person is, what identity of “personhood” could you build? You almost certainly don’t have enough data points to get it totally right, but even the information you have might lead you to completely wrong theories. Maybe you’d see that someone bought shoes, so you’d assume they had feet. Unless you thought that shoes were, uh, some sort of house—like how a snail uses a shell—and then what would people look like? Assuming you knew what shoes were. Or feet. Or the act of buying. Is the universe a snail? Or bipedal? We can’t know, we just know it orders a bunch of shoes. Not that we know what shoes are.
There are many ways to think about the universe—online shopping analogies notwithstanding—and removing time has been a requirement for higher-level physical equations for centuries:
How could something be the cause of Earth’s motion around the sun if there is a different and equally valid point of view according to which Earth isn’t moving at all? If motion is relative, an observer is free to adopt the point of view that all motion is defined relative to him. To resolve this impasses and be able to speak of causes of motion, Newton proposed that there must be an absolute meaning to position. This was, for him, position with respect to what he called “absolute space.” Newton argued that it was the Earth and not the sun that moved absolutely.
No one has ever seen or detected absolute space. No one has ever measured a position that was not a relative position. So to the extent that the equations of physics refer to position in absolute space, they cannot be connected to experiment. Newton knew this and it didn’t bother him. He was a deeply religious thinker, and absolute space had a theological meaning for him. God saw the world in terms of absolute space, and that was enough for Newton. He would put it even more strongly: Space was one of God’s senses. Things exist in space because they exist in the mind of God.
Einstein did it, too, though without Newton’s piety:
The picture of the history of the universe, taken as one, as a system of events connected by causal relations, is called the <i>block universe</i> The reason for that perhaps peculiar name is that it suggests that what is real is the whole history at once—the allusion is to a block of stone, from which something solid and unchanging can be carved.
The block universe marries space and time. It can be pictured as a kind of spacetime, with three dimensions for space and a fourth for time. An event taking place at a moment of time is represented as a point in spacetime, and the history of a particle is traced by a curve in spacetime called its world line. Thus, time has been completely subsumed by geometry; we say that time has be spatialized or geometricized.
So our understanding of time and space changes to fit the current theories, all of which are simple enough and consistent enough to give physicists workable approximations of the world. But they cannot extend too far backwards, or too far forwards, or too big, or too small, because then things get weird. For example, you jump back to the big bang: everything in the universe is expanding outwards from this one event:
The electromagnetic arrow of time can also be explained by time-asymmetric initial conditions. At the universe’s beginning, there were no electromagnetic waves. Light was produced only later, by the motion of matter. This explains why, when we look around, the images the light carries gives us information about the matter in the universe. If we just went by the laws of electromagnetism, it could be otherwise. The equations of electromagnetism allow the universe to being with light traveling freely. That is, light would have formed directly in the Big Bang rather than being emitted from matter later on. In a universe like that, any images of objects that light carried away from matter would be swamped by the light coming straight from the Big Bang.
In other words, if everything originated in The Big Bang, then light originated there too. And we should all be blasted out by light. All the time. And maybe we are. Maybe our light is different light. But then, why didn’t what we’ve chosen to call light originate in The Big Bang? Light couldn't have begun at The Big Bang, or we'd be buried by it. So the universe changes over time. So it's possible time is more than an arbitrary construction. Got it.
Let’s go the other direction—not the beginning, but the end:
The simplest way to avoid the eternal dead universe would be if the universe had enough density of matter to stop the expansion and cause it to collapse. Matter attracts matter gravitationally, and this slows the expansion, so if there is enough matter the universe will collapse to a final singularity. Or perhaps quantum effects will stop the collapse and “bounce” the universe, turning contraction into expansion leading to a new universe. But there doesn’t seem to be enough matter to reverse the expansion, let alone counteract the tendency of dark energy to accelerate it.
So nobody knows what’s going on outside of our narrow sliver of experience. Time Reborn: Nobody Knows What’s Going On was probably the working title.
“Every experiment is a fight to extract the data you want from the unavoidable presence of noise coming from outside your imperfectly isolated system.” Science has gotten so good at ignoring the noise and working within our limitations that we’re starting to believe that the universe is as simple as the math that approximates it:
Math in reality comes after nature. It has no generative power. Another way to say this is that mathematics conclusions are forced by logical implication, whereas in nature events are generated by causal processes acting in time. This is not the same thing; logical implications can model aspects of causal processes, but they’re not identical to causal processes. Logic is not the mirror of causality.
At the end of Time Reborn, the reader will not have a pet cosmological theory or an answer to why quantum mechanics fails to scale up past the microcosmic level. Whether or not time will be reborn—if the relativities killed it off in the first place—requires an understanding of the many competing theories of time as an concept:
We speak easily of “here” and “there” while believing that near and far objects are equally real. So some philosophers argue that “now” and “the future” are not really very different from “here” and “there”; they all denote a certain perspective that influences what you see around you but does not affect what is real.
Or:
Temperature is like this: Macroscopic bodies have temperatures, but single particles don’t, because the temperature of a body is the average of the energies of the atoms that make it up. Some physicists have proposed that time, like temperature, is meaningful only in the macro world but not relevant at the Planck scale.
It isn’t a failure that Time Reborn doesn’t answer questions—what is important is realization that the framework in which we do physics, rely on math, and oversimplify the world to fit our algorithms and equations is examined and excoriated as wish fulfillment. The digital age continues to reduce people to numbers and alters the world to fit the lens of self-effacing code. It is increasingly important to avoid a fallacious “natural” justification for mathematical simplicity in attempting to understand the universe, else risk giving credence to a "true" or "pure" mathematical view of markets or web traffic or any other social construct.
The most radical suggestion arising from this direction of thought is the insistence on the reality of the present moment and, beyond that, the principle that all that is real is so in a present moment. To the extent that this is a fruitful idea, physics can no longer be understood as the search for a precisely identical mathematical double of the universe. That dream must be seen now as a metaphysical fantasy that may have inspired generations of theorists but is now blocking the path to further progress.