The Order of Time by Carlo Rovelli (Pt 3 of 3)

[For Part 1 of the review, click here]

The final part of Carlo Rovelli's The Order of Time pulls away from the physics and takes the human view of the phenomenon. "We inhabit time as fish live in water." The very source of time, suggests Rovelli, is our own perception. We see things emerge, unfold, become; the process runs forwards, never backwards. Evolution is a continuous and one-way process, as is entropy. "The entire difference between past and future may be attributed solely to the fact that the entropy of the universe was low in the past."

Rovelli asks us to imagine being on a high mountain, looking down into a valley covered by a sea of white clouds. The surface of the clouds gleams white, immaculate. We start walking down. The air becomes more humid, less clear, the sky no longer blue. Eventually, we find ourselves in a fog. What happened to that well-defined surface of the clouds? "It vanished. Its disappearance is gradual; there is no actual surface that separates the fog from the clear air above. Was it an illusion? No, it was a view from afar. It's like that with all surfaces. This marble table would look like a fog if I were shrunk to a small enough, atomic scale. Everything in the world becomes blurred when seen close up."

This is actually a huge insight, not only in terms of time and physics, but indeed economics and politics too - detail blurs perception. We tend to want our truths clear-cut; yet the more we drill down, the more complex it all becomes.

Back down at that atomic level, the glass of hot water left to cool on the kitchen table is abuzz with vibrating molecules shedding heat energy over time. It is the act of observing those blurry vibrations (always slower than before, never faster) that generates time. Rovelli speaks of 'thermal time' and 'quantum time', though this is not time as we experience it, rather it is the granular, discrete, packets of time, determined by the speed and position of a molecule. For it is down here, that the direction and evolution of time becomes a phenomenon of physics, and not a matter of human perception.

"It took us thousands of years, but in the end we managed to understand the revolving of the heavens: we understood that it is we who turn, not the universe..." furthermore "...perhaps the flow of time is not a characteristic of the universe, but is due to the particular perspective that we have from our corner of it." The entropy of the universe was low in the past, as the second law of thermodynamics demands, it is increasing. As it does so, "memories exist, traces are left - and there can be evolution, life and thought."

Yes. Rovelli moves into the human sphere; it is memory that allows our consciousness to perceive the passing of time. Marcel Proust's famous madeleine cake from À la recherche du temps perdu (those memory flashbacks prompted by long-forgotten smells and tastes) gets the status of chapter heading. "Proust could not have been more explicit writing... 'Reality is formed only by memory'. And memory is a collection of traces, an indirect product of the disordering of the world, of that small equation, ΔS ≥1." Here on earth, the human brain is the ultimate time keeper, storing across a network of many billions of brains, past, present and to come, the memories and the traces of lives measured down the millennia. "We are time. We are space, this clearing opened by the traces of memory inside the connections between our neurons. We are memory. We are nostalgia. We are longing for a future that will not come."

The final chapter heading, The Sister of Sleep, looked familiar. Of course - it is also a chapter heading from Tischner/Żakowski, Death, our Sister. Tischner is quoting St Francis of Assisi; Rovelli is quoting Bach. Death marks the end of each individual human's time - then what? "We see just a tiny window of the vast electromagnetic spectrum. We do not see the atomic structure of matter, nor do we see the curvature of space." We are too limited in our understanding to comprehend. The nearest most of us can get is through music, he suggests. "Song, as St Augustine observed, is the awareness of time. It is time. In the Benedictus of Beethoven's Missa Solemnis the song of the violin is pure beauty, pure desperation, pure joy. We are suspended, holding our breath, feeling mysteriously that this must be the source of meaning. That this is the source of time. The song fades and ceases. The silver thread is broken... the earth returns to dust. We can close our eyes, rest. This all seems fair and beautiful to me. This is time."



On his Wikipedia page, it says that Rovelli sees the conflict between science and religion as unsolvable because most religions demand the acceptance of some unquestionable truths, while science is based on the continuous questioning of any truth. Yet it is clear from this book - as it is from Stuart A. Kauffman's Humanity in a Creative Universe - that the author's position on their being some greater, mystical power at work is far removed from that of Richard Dawkins. We are far more than meat robots in an accidental universe!

This book is relatively accessible to the general reader (if you made it through Hawking's A Brief History of Time you'll find this easier and - dare I say - more artistic). Every science writer has their strengths; Rovelli's for me has been his understanding of the role of entropy in the universe. Here and there, he argues in favour of his loop quantum gravity theory; but then you'd have to understand string theory to get this. Shortcomings? I'd like to have read what Rovelli makes of dark matter and dark energy (and how a universe that's expanding at an accelerating rate sits with second law of thermodynamics). And also about quantum entanglement, superluminary transfer of quantum information (which in effect suggest that there is such as thing as 'instantaneous', by inference positing the theoretical possibility of universal time).

Above all, how the idea that atoms seem to defy entropy; electrons in position around their neutrons for ever. Are they only defying entropy - or are they defying time itself?

I like the small hardback format, the paper stock, the clear 12/14pt type and page layout; physically the book is a nice object to have in your hand.

Many thanks to my father for getting me the book; now I look forward to reading Carlo Rovelli's Seven Brief Lessons in Physics; look out for my review on this blog in early June.

This time last year:
The year's most beautiful day

This time four years ago:
W-wa Wola became W-wa Zachodnia Platform 8 two years ago today 

This time five years ago:
From yellow to white - dandelions go to seed

This time six years ago:
The good topiarist

This time eight years ago:
Wettest. May. Ever.

This time ten years ago:
Blackpool-in-the-Tatras