I’ve been reading science texts almost as long as I’ve been reading anything. Over those years, many scientists and science writers have taught me much of what I know about science. (Except for a Computer Science minor, and general science classes, most of my formal education was in the Liberal Arts.)
Recently I read Time Reborn (2013), by Lee Smolin, a theoretical physicist whose personality and books I’ve enjoyed. I don’t always agree with his ideas, but I’ve found I do tend to agree with his approaches to, and overall sense of, physics.
However in this case I almost feel Smolin, after long and due consideration, has come around to my way of thinking!
I had high hopes for this book based on things I’ve seen in interviews, and it didn’t disappoint. I grinned right off the bat, when in the Preface, Smolin writes:
More to the point, I no longer believe that time is unreal. In fact, I have swung to the opposite view: Not only is time real, but nothing we know or experience gets closer to the heart of nature than the reality of time.
Which is what I’ve been saying for a long time. (See all these posts.)
He paints his view as radical, and within science today it rather is. The first half of the book explores this view of time as not real or fundamental in modern physics. A key aspect Smolin explores is how the Newtonian view created a timeless physics that has pervaded our view of reality.
The book, in the context of time, also explores cosmological theories; how we create them, and how we should view them. A third aspect explores a relationist viewpoint Smolin feels is fundamental (he and I diverge a little on this, but his ontology does implicitly feature objects with relations).
In the Introduction Smolin writes:
The notion that our universe is part of a vast or infinite multiverse is popular — and understandably so, because it is based on a methodological error that is easy to fall into. Our current theories can work at the level of the universe only if our universe is a subsystem of a larger system. So we invent a fictional environment and fill it with other universes. This cannot lead to any real scientific progress because we cannot confirm or falsify any hypothesis about universes causally disconnected from our own.
This is a point of view I wish was more widespread. Multiverse theories are science fiction. They may be well-grounded science fiction, but they’re still fiction. Theories can be so interesting and exciting that it’s easy to forget this a little.
(Smolin does still favor the cosmological natural selection idea he presented in his first book, The Life of the Cosmos. What does make it different from most multiverse ideas is that it’s serial, not parallel. Its value, in fact, comes from that. Smolin is fine with other serial multiverse ideas, such as the conformal cyclic cosmology due to Roger Penrose.)
Subsystems are a key aspect of this argument. Science reduces reality and studies subsystems in as much isolation as humanly possible. But no real system functions that way. Everything real is affected by, and in turn affects, everything around it. Our theories don’t acknowledge that.
Worse, our view of subsystems is part of what contributes to the notion that time isn’t real. Our abstraction of reality into a simplified subsystem creates something timeless, something Platonic.
We invent the curves and numbers of mathematics, but once we have invented them we cannot alter them.
Or perhaps we discover them, and as Smolin much later in the book discusses, the “unreasonable effectiveness of math” is because we derived it from the physical world. Its regularities are the regularities of reality.
Smolin presents a very good analogy for a relationist view. He starts with the simple idea of the two neighbors to a house on a street. In one dimension, only two are possible. There can also be a neighbor behind and one across the street, so in two dimensions, four neighbors are possible.
From there he moves to an apartment in three dimensions and six neighbors are possible. The number goes up by two for each dimension added. In the real world, there are only three dimensions, so six is the maximum number of immediate neighbors.
Now consider a cellular network. In such networks, most nodes are just one logical step from each other. One phone can call any other phone. (Physical multiple hops occur, and in most networks the path through the network is created anew for each connection, if not each packet of information.)
In such a system, everyone is a neighbor to everyone else. Reality is defined by the active connections from moment to moment. “Distance” is an entirely virtual concept, and there are as many dimensions as there are connections.
I’ll note that in both examples, living abodes and cell phones are the primary object — the relations are consequential. And as Smolin concludes:
The relational revolution is already far along. At the same time, it is clearly in crisis. On some fronts, it’s stuck. Wherever it is in crisis, we find three kinds of questions under hot debate. What is an individual? How do novel kinds of systems and entities emerge? How are we to usefully understand the universe as a whole?
Note the importance of “individual” and “entities” — relations are important, possibly even fundamental, but I can’t see them as primary.
There is a great deal in the book I’d like to share. I highlighted a lot of bits in the text. (I may need a bigger post.)
He starts by pointing out Heraclitus warned us that “Nature loves to hide.”
And indeed she does; consider that most of the forces and particles that science now considers fundamental lay hidden within the atom until the last century.
But each of us, as infants, learns about one very apparent and important part of nature: gravity. One of our most pervasive, vexing, and puzzling forces.
Smolin’s touch as a writer is expressed in part by how he frames this in the context of his own child’s question (one many parents have heard): “Why can’t I fly, Daddy?”
This leads to an examination of humanity’s ideas about motion and falling. The ancients knew about the parabola, but it wasn’t until Galileo in the early 1600s that humanity realized objects fall on parabolic paths. (Smolin points out it could have been discovered much earlier. Other civilizations had the same tools Galileo did, but humanity wasn’t ready for the analytical approach until that time. It was a way of thinking that led directly to the Scientific Revolution.)
Meanwhile, watching the heavens, we went from Ptolemy’s Earth-centric view to Copernicus’s Sun-centric view, both of which posited circular orbits. It wasn’t until (again) the 1600s that Kepler determined orbits were ellipses.
It then took Newton (late 1600s) to tie those two together. Parabolas and ellipses (and circles) are all conic sections. Suddenly the Heavens and the Earth were the same thing, and they were mathematical. And timeless.
I especially enjoyed Smolin’s take on the Block Universe Hypothesis (aka eternalism), which is quintessential timelessness. The BUH comes from a misapprehension of Special Relativity.
We’ll concern ourselves with two concepts from special relativity. The first is the relativity of simultaneity. The second, which follows from it, is the block universe. Each was a major step in the expulsion of time from physics.
Smolin spends a chapter exploring this, and comes to the same conclusion I did. And, indeed, the view has been a huge contributor to the notion that time isn’t real. [See: Blocking the Universe and Back to Block]
The TL;DR is that the relativity of simultaneity is better understood as simultaneity being virtual, rather than relative. It’s only valid locally. Simultaneity with causally separated events can only be determined once light from that event arrives.
A fundamental tenet of SR is that we cannot speak validly about any event outside our light cone until we receive light from that event.
[I’ll mention that everyone favoring timeless views quotes the letter Einstein sent as consolation to the grieving widow of a friend, but Smolin mentions an interview by Rudolf Carnap where Einstein expresses a different view. As Carnap put it, that “there is something essential about the Now which is just outside the realm of science.”]
Smolin uses the example of a tossed ball… on Oct 4, 2010, at 1:15 PM, on the east side of High Park in Toronto; thrown by Danny the novelist to Janet the poet he just met — physics is not isolated from real life.
But the physics analysis of that tossed ball is. It becomes data frozen in a table of numbers. Danny, Janet, the location, the time, even the ball itself, all become irrelevant. The ball’s flight is represented by a one-dimensional curve through a Newtonian spacetime that effectively spatializes time into a series of static snapshots.
This abstraction of isolated subsystems pervades physics and is just one of many implicit arguments physics makes that time isn’t real:
- Phase space diagrams track the dynamics of a system in an imaginary space (such as momentum vs position), and either spatialize time or ignore it completely.
- That the basic laws of physics work equally well backwards (which often leads to using entropy as time’s ratchet to explain time’s arrow).
- Minkowski spacetime, used by Einstein in Special Relativity, ratifies the idea that time is spatial (and leads to eternalism).
- Newtonian physics is seen as causally determined, which suggests time is irrelevant since any future can be known from the present. The Newtonian universe can never surprise us.
- The notion that time began with the Big Bang.
Smolin argues that unreal time is a mistaken, limiting, and ultimately incoherent, view. The second part of the book is his argument why.
He folds in a cosmological argument (because time, after all, is a cosmological issue). One problem is that physics theories divide reality into two parts: a dynamic part, the system being studied, and an implicit static second part, the environment of the system — all the physical assumptions made about the subsystem — effectively the rest of the universe.
This division of the world into a dynamical and static part is a fiction, but it is an extremely useful one when it comes to describing small parts of the universe. The second part, assumed to be static, in reality consists of other dynamical entities outside the system being analyzed. By ignoring their dynamics and evolution, we create a framework within which we discover simple laws.
Other then General Relativity, nearly every other physics theory assumes a background of spacetime. On top of that, our theories, including General Relativity, are approximate theories known as effective theories (because they’re effective, but only in a specific — typically low-energy — context).
So the success of physics to this day is entirely based on the study of truncations of nature, which are modeled by effective theories. The art of doing physics at the experimental level is all about designing experiments to isolate and study a few degrees of freedom, ignoring the rest of the universe.
Which works great for small scale stuff. These theories have changed our world because they’re so effective, but (Smolin argues) can’t be usefully extended to cosmology with has no static outside. Cosmological theories cannot be bipartite. There is no outside.
Smolin extends this to small systems with his principle of no isolated systems.
Experiments deal with noise (which they try hard to eliminate), but they cannot deal theoretically with city-wide power failures, asteroids, terrorists, plane crashes, earthquakes, or expanding bubbles of spacetime destroying everything in their path at light speed.
Yet these things are possible (albeit unlikely) outcomes to an experiment. (In the MWI, this is one source of the preferred basis issue. A universal wavefunction needs to include all possible outcomes.)
And if relational theories are true, then isolation is all the more the wrong idea and, to the extent it’s successful, might actually be misleading.
I haven’t gotten much into the second part and his arguments for time as real, but this has gotten long. I’ll either come back for a second round or leave it for the interested reader.
(It might not be immediately. I’m reading Fundamentals: Ten Keys to Reality by Frank Wilczek right now. I’ve had it on hold at the library since May 14, and it finally came available. More people are on the waiting list behind me, so I want to get through it ASAP.)
I’ll just say that Smolin finds physics much more rational, explicable, and useful, if time is taken as real. I entirely agree.
Stay in real time, my friends! Go forth and spread beauty and light.