The Order of Time Kindle Edition

Like consciousness, time is a subject that no philosopher or physicist has ever managed to nail down completely. Thanks to their slippery character, being so close to us (the first one IS us) they are endless sources for fountains of speculation. In this book, Rovelli's subject is time, but consciousness comes into this narrative as well.

Rovelli is a "time denier". OK, that's being a little unfair but not by much. What he denies is that there exists an independent, fundamental property or quality of the universe that is time. Of course the universe is full of movement and change, events unfolding into other events. His basic position is that time emerges into our perspective, our viewpoint, from these phenomena, but it is merely an illusion. The movement is real, the changing is real, but the time in which all of this seems to occur is nothing more than a manifestation of human (possibly animal) mind and the illusion, in turn, is supported by the entropy generated in the functioning of our brains.

The book (not long read) is divided into three parts. In the first Rovelli covers the various sub-disciplines of physics and their temporal implications (or lack thereof). He begins with classical physics (the equations work backwards in time), and moves on to General and Special Relativity, and quantum mechanics. Here he demonstrates that our simple intuition of a universal time flowing from past to future is untenable. Time, mind-independent time, if it exists at all, cannot be like that. In part two he further demolishes time. Not only is it not what we think, in and for physics, it doesn't really exist at all; even the present is an illusion! In part three, he puts time back together for and in the perspective of an subjective viewpoint.

He argues it is the fact that we view the world from a perspective, that when we perceive the world we inevitably blur the details into a sort of summary or gestalt for our perspective, that causes time to appear to mind, The physics supporting that appearance comes down to thermodynamics. Human time, brain time, is "thermal time". Certainly Rovelli thinks thermodynamics (in particular the 2nd law) is real, but while responsible for what consciousness perceives of time and so a real enough subjective experience, from the 3rd party perspective of physics, change is real, but time is a mirage.

This book is written for a lay audience. There is almost no math in it (what there is appears in footnotes), and it defends a view common to much of the physics and philosophy community. To be sure Rovelli differs a bit from some of his peers. He argues that relativistic "block time" is no more a "true portrait of objective time" than any other theory. In Rovelli's view remember there is no such thing as "objective time".

In 2015 a philosopher (Roberto Unger) and a physicist (Lee Smolin) wrote "The Singular Universe and the Reality of Time". This book (reviewed by me on Amazon) makes precisely the opposite case from that of Rovelli. Of course they recognize what Relativity and quantum mechanics imply about time, but they maintain, nevertheless, that a notion (and reality) of objective, "universal time", is more fundamental than any other phenomena of the universe, even more than space! Rovelli mentions this book in a footnote and admits that Unger and Smolin's view "is defensible", but he leaves it there and never addresses what is defensible about it.

The Unger/Smolin book goes against the grain of 95% of today's physicists. Personally I agree with Smolin and Unger. The fact (thanks to limiting effect of the speed of light) that we cannot map our present to any present in a remote galaxy, or even the nearest star does not mean there is no present there, in fact everywhere. Something is happening, NOW, everywhere in the universe. We do not know what it is, but that does not mean the present isn't real as Rovelli believes. Had Rovelli directly addressed Unger and Smolin I would have given this book another star. Had he not mentioned them at all, I would have taken another away.

In summary this is a decent and well written book advocating for a particular view of time (or no time) that I happen to think is wrong, but what do I know? It happens to be the dominant view in physics today. Rovelli is a well respected physicist and a good writer. Those of you interested in the subject will find this book valuable whether you agree with the author or not.

The Order of Time is one of the few books that can change the perception of the world as we see it. For example a human being is not a thing at all, but a process, »like the cloud above the mountain, it's a complex process which enters and exits food, information, light, words and so on. Knot of knots in a network of social relations, in a network of chemical processes, in a network of emotions exchanged with its own kind." I've also learned something about entropy. »What makes the world go round are not sources of energy but the sources of low entropy. Without low entropy, energy would be diluted into uniform heat and the world would go to sleep in a state of thermal equilibrium - there would no longer be any distinction between past and future, and nothing would happen. Traces of the past exist, and not traces of the future, only because entropy was low in the past."
Really a great book that transforms the way we perceive "the reality". It probably should be read more than once. The final thoughts of the writer on the meaning of life and death are also beautiful. Almost a little poetic. The book is written in an intelligible way.

Carlo Rovelli has the brilliance of Stephen Hawking and Albert Einstein and the communicative skills of Carl Sagan. Otherwise he is an Italian theoretical physicist that specializes in quantum gravity and is a proponent, if not quite an advocate, of loop theory. Beyond that he is a philosopher with a heart for ancient poetry and love.

And he brings all of it to bear in this delightful book about time, which, in the end, is life, and everything, including the context in which it unfolds. It would be in error to suggest that time doesn’t exist, but it would be equally in error to suggest that time is as simple as the continuum we record with our clocks.

What I like most about the book is the fact that Rovelli recognizes that philosophy and science, if not two sides of the same coin, are cousins. He refers to Proust, which few scientists do, and suggests that while reason is among the best tools available for interpreting our “collective delirium,” it is “only an instrument, a pincer.”

The science and the prose are very accessible. You will, however, have to be willing to think abstractly, a skill that in our wired, binary world seems to be greatly dissipating. And he is the first scientist I have read in a while who takes time to explain why the problem is sometimes not the science itself, but the limitations of language. Language is a human construction and has not kept up with our scientific revelation. Which is why theoretical physicists sometimes seem to be speaking another language. If only there was another language that was constructed in the world as we know it today, our communication would be so much easier and our knowledge would expand more rapidly.

It would be impossible to summarize the knowledge contained in this book. You really have to read it. Here is a start, however: “The world is not a collection of things, it is a collection of events.” If you can comprehend that the rest is largely additional perspective.

And if the idea that universal time doesn’t exist in any absolute sense seems a stretch, consider Rovelli’s simple explanation (I’m paraphrasing): People never used to worry about clocks. They worried about the cycle of sunshine and darkness. But that cycle is different in every single village, town, and city on the planet. The cycle varies both east to west and north to south. And back when we used to spend our lives in our little village we didn’t care. But then the scientists and engineers invented trains to take us from one village to the next. And people needed to know when the train left their village. But how can you develop a timetable when every village has its own time? You can’t. But, at the same time, it’s not quite practical to say that the whole world has just one time. Farmers don’t care what the sun is doing in London. They care what it’s doing on their farm. (China actually has no time zones by edict. The entire country is on Beijing time and there are significant practical limitations.) The solution was the time zone, and it’s a compromise. Time zones are a construct and practical in the local sense, but highly inaccurate when talking about the universe. In the language of theoretical physics, they don’t exist.

Eastern philosophers believe that reality is not knowable. It is real, but is made up of an infinite number of variables. We can only comprehend or think about a handful at a time. A tree is real. I can touch it and smell it. But it is not entirely knowable because there are too many variables (e.g. altitude, climate, soil, etc.) that define each tree for me to know them all. Time is the same way. Time is real but it is not knowable. Throw in the limitations of language and it begins to look like an illusion.

To his great credit, Rovelli admits that there is much we don’t know. Think of a Seurat painting that has been blacked out. We have exposed a few, perhaps 10% (my number), of the original dots of pigment. It’s a lot, but we’re still guessing as to what the underlying picture is.

And that’s pretty exciting. The key to our understanding to date, however, is the second law of thermodynamics which states that entropy can never decrease. It’s critical to our understanding of time, as Rovelli explains. Personally I’m not convinced it’s inviolate. Perhaps we just haven’t uncovered enough dots of pigment yet. If entropy could work both ways it would explain a lot, but attraction does not equal fact. (Entropy obviously has a big role in causality, of course. Bidirectional entropy would be a huge boost for inductive reason.)

It’s a short book and even if you get through a small amount of it you will learn a lot. Beyond writing in an accessible way, Rovelli comes off as very personable. The perfect person to sit down and share a cup of coffee with. If only he had the time. (Sorry)

A marvelous book that I highly recommend.