On the Equality of All Things: Physics and Philosophy

by Carlo Rovelli

What can we really know about the world around us? Or is there beauty in daring not to know?

With clarity and lightness, acclaimed physicist Carlo Rovelli takes us on a journey of enlightenment, to the speculative frontiers of modern physics and the boundaries of thought. There is no fear in testing their limits, he suggests – not least because there may be no final ground to reach.

Here Rovelli shows us that electrons and minds, stones and laws, judgements and galaxies are not essentially different in nature from one another, but rather ideas that illuminate each other. Reality, he reveals, is shaped by a continuous play of reflections. From this emerges his visionary insight: the equality of all things.

Like the ancient Chinese philosopher Zhuangzi, who dreams he is a butterfly and wakes unsure whether he is Zhuangzi dreaming to be a butterfly or a butterfly dreaming to be Zhuangzi, Rovelli invites us to see reality anew, recognizing that our knowledge is coherent but also uncertain and circular. We are made of the same stuff as the rest of reality – and so we are, in a deep sense, home in the world.

Genres: Science, Philosophy, Nonfiction, Physics, Audiobook

192 pages, Hardcover

First published September 15, 2026

About the author

Carlo Rovelli is an Italian theoretical physicist and writer who has worked in Italy and the USA, and currently works in France. His work is mainly in the field of quantum gravity, where he is among the founders of the loop quantum gravity theory. He has also worked in the history and philosophy of science. He collaborates regularly with several Italian newspapers, in particular the cultural supplements of Il Sole 24 Ore and La Repubblica.

Reviews

[Alice · Rating 5 out of 5]

Unknowingly, Rovelli has created a field of his own.
Everything that enters it—or even brushes against it—emerges charged with beauty and passion. We need no CERN to prove that, we just have to keep reading his works.

[Brian Clegg · Rating 4 out of 5]

There is a wide gulf between the worldviews of physicists and philosophers. Many physicists present a rather sweetly naive, child-like view of the world, where philosophers bring a distinctly more adult, cynical tone. This being the case, it can be a little worrying when a physicist dips a toe into the philosophical mire. Infamously, in The Grand Design, Stephen Hawking and co-author Leonard Mlodinow told us that philosophy was now dead because science could deal with anything it had previously been needed for.

Thankfully, Carlo Rovelli is not trying to do away with philosophy, though it has to be said that when he veers into the topic that physicist's naivety can make it feel like the philosophising of an earnest eighteen-year-old. Take the opening paragraph, which tells us 'electrons and minds, stones and laws, judgements and galaxies do not essentially differ in nature from one another. They are notions that illuminate each other'. I almost expected a Pink Floyd soundtrack. But though Rovelli doesn't say philosophers are redundant, he does delight in telling them they're wrong, for example 'I feel there is a whole branch of contemporary philosophy that is trapped inside this mistake. The mistake is to believe that the concepts we have are necessarily adequate for understanding reality, even beyond the context in which these concepts were shaped.'

It might seem, given this concern, that I've over-rated the book, but where he primarily focuses on the physics - which is more of the book than you might think, Rovelli absolutely deserves those four stars. Admittedly, as always, his presentation of physical theory does not give us an objective broad picture of the current debates, but only his own personal viewpoint - but he does that very well and approachably, giving considerably more detail than he has often done in these short books.

One major basis of his thesis is the relational interpretation of quantum theory, which builds on the idea that very few physical observations can be made in isolation - we always have to consider a physical system in its context. (This feels very much in opposition to the traditional physics approach of pretending we can deal with perfect isolated systems.) Inevitably this also brings in relativity. It was particularly interesting comparing Rovelli's section on 'the flow of time' with some very different views in Jim Al-Khalili's recent On Time.

Occasionally things seem to go a little adrift. At one point we are told that there is no such thing as absolute certainty of anything - effectively, there are no facts. Can’t I be certain that my entire body is not currently inside my own stomach? Even Rovelli seems not to be convinced by his own statement as soon after he states a physical observation is a 'fact'.

All in all, for me despite the dips into philosophical noodling, this book had far more meat to it than most of Rovelli's compact hardbacks. Probably his best book yet.

[Natalia Gastélum · Rating 4 out of 5]

“I believe we can have a much richer and more nuanced understanding of what it means for us to learn, and of what morality is for us, precisely by taking into account how morality is not rooted outside us but within us — and by recognizing how our knowledge is embodied. Morality is a powerful force. It is powerful because it is a part of who we are, and we cannot change it arbitrarily.”

“Reality is nothing more than the name we give to the content of everything we know about it, and to the acute awareness of the profound incompleteness of our knowledge.”

“Physicists rarely invent anything without first getting permission from a philosopher.”

“We are not pure reason, or pure spirit, contemplating the world. We are fragile and confused pieces of this world, caught within the vortices of relations that allow us to describe it.” Beautiful!

[Chris Leonard · Rating 3 out of 5]

Rovelli is a brilliant writer. This confused the hell out of me. The central message is beautiful: that we’re all more connected than we think (through science!). The prose is excited, often funny, and yet so difficult to keep up with. Even with rovelli’s signature hedging comments, I often felt left behind. This book enjoys tying knots in your brain and then painstakingly helps you understand the larger picture of things, whilst you’re stuck in this state of confusion. The combination of some of my favourite philosophers showing up in a science book was fantastic, but make me access parts of my brain I haven’t used in a while. At times while reading this, I was reminded of completing the required reading the morning before a seminar. Despite its short length, this is chewy work. But if you work at it, you find some moments of beauty. I implore anyone who gets close to copy to read p. 89 and also the afterword.

[Jordan Frances Camille · Rating 4 out of 5]

Carlo Rovelli presents a fascinating and thought-provoking exploration of the world around us, bringing together philosophy and physics in a way that feels considered, often candid, and surprisingly accessible. It’s definitely the kind of book that requires your thinking hat!

I loved exploring the idea that everything is relational and there is no ultimate fixed reference point: even time, space and speed are relative. Rovelli encourages us to keep an open mind and to accept that our knowledge of anything will always be incomplete, leaving us open to continue learning and evolving our understanding of reality.

As someone who hasn’t read many books on physics or philosophy before, but has a lot of curiosity, I found this remarkably accessible. Complex ideas are clearly explained and illustrated with examples that helped me get my head around concepts that might otherwise have felt daunting. I also really appreciated the extensive footnotes, which offer plenty of further reading for anyone who wants to dig more deeply into a particular idea.

A challenging but rewarding read that left me thinking differently about how we understand the world and our place within it.

Thank you to Carlo Rovelli and Penguin Press for providing an advance reading copy via NetGalley. All opinions are my own.

[Lauren Levine · Rating 2 out of 5]

I had to read this twice - because the first time I read it from a not very charitable 'how do I defend philosophy' POV. I feel like generally Rovelli invalidates the discipline based on some bad philosophers, and is far more charitable towards scientists.

Good bits of physics.

1. We are frequently misled by applying concepts outside their domain of validity - e.g. Newtonian physics works up until a certain point, but we go wrong if we try to apply it to quantum phenomena. If you generalise from our day to day on Earth, you'll often be wrong - we're weird, we are a space that is small, has objects, is surrounded by air, is quite static and has constant gravity
2. All properties are perspectival and relative to something else. There are no 'absolutes'. Measured express a relation between the measurer and the property measured, and the measuring system will incorporate traces of the measured to allow it to be quantified. This means all knowledge from Y of X is accompanied by some physical traces in Y.
3. We predict a world that is probabilistic, but also granular or lumpy
4. We happen to be in a world where time has a particular direction, but this is simply a byproduct of the laws that we exist in. We have an 'entropy gradient' between systems, and this is partly what allows us to remember.

Philosophy & Physics relationship

1. Philosophers play inadequate attention to science: (1) some do, lots don't. Lewis? I read a bunch of physics on Time (2)
2. According to Rovelli, *all* properties are relative, and philosophers don't account for this. That seems wrong. Scientific properties may be, ethical ones may not. We don't measure e.g. the rightness of an action or think we can - ethical or normative or aesthetic properties seem to be a different kind of thing.
3. Rovelli doesn't pay attention to functional equivalents - a particular physical configuration is irrelevant or may not be the kinds of correlation we are interested in. Physical patterns of different thoughts of love may be completely different but have similarish results.
4. Both rely on a via negativa - lumpy probabilities means we can say something does not or does exist; philosophy often shows that something cannot happen - in a way Rovelli ignores.
5. The correlation in (2) is silly. Yes there's a correlation (something changes in the physical world when we know something) but it's not the case that the physical traces can be usefully synthesised or bucketed so we can use them.
6. Rovelli asserts that all certainities are a matter of degree. But logic? A = A? And there have to be some certainties about the laws and rules of science that Rovelli himself asserts? I think often philosophy is aimed at eliminating inconsistency rather than necessarily making claims. There's also some crazy statements - e.g. if finding a solid foundatin for all our thought were an achievable goal, we would already have acheived it by now.
7. Total strawman of Kant assuming space is fixed and a priori - it's for kant how we are able to understand the world (indeed the limits of our own perspective)
8. Dangerous relativity.


Gems:
We instinctively mistake local peculiarities for universal truths
There's something lovely about the description of memory - we're only able to remember because the event will leave traces in our brains. But that is an increase in disorder or entropy, so suggests a net loss of information - there's a kind of sacrifice involved in memory
Reality does not exist in space and it does not unfold in time. it is a fine, intricate and fragile fabric, like Venetian lace

[Dennis Tempelman · Rating 4 out of 5]

Rovelli legt op een 'relatief' makkelijke manier de quantum fysica uit. Of je het direct zal begrijpen is een tweede, maar tijdens het lezen krijg je in ieder geval het idee dat het makkelijker is dan het in werkelijkheid is. De meerwaarde van dit boek zat hem voor mij vooral in nadenken over de lessen van Rovelli. Ondanks dat het geen dik boek is, is het zeker geen boek dat je één ruk uitleest. Wat vooral is blijven hangen is dat woorden als stilstaan en bestaan eigenlijk niks betekenen en dat alles in relatie tot elkaar gezien moet worden.

[Alexander Wright · Rating 5 out of 5]

Among physicists, Rovelli is a rare breed. His writing is clear, concise, and beautiful, explaining the web of interrelationships that comprise our world with admirable ease. I have found his works essential in breaking through some of the more esoteric, academic walls in QM, and this is a valuable addition to his canon.

[Irene · Rating 5 out of 5]

Rovelli never fails to make me re-examine my own biases and (re)learn about the intrinsic relative nature of reality. And he does it so beautifully.

[Jessica · Rating 4 out of 5]

Thank you Scribner for providing an ARC for review consideration via NetGalley! All opinions are my own.

I discovered another great writer in Carlo Rovelli to continue learning about physics through his approachable teachings. On the Equality of All Things was a quick read focusing on the immense discoveries seen in quantum theory, general relativity, observers, time, space, existence, and morality.. Rovelli pushes thinkers to be open to adjustments to our beliefs as once-inconceivable ideas come to light. He also warns that the concepts we use on Earth to measure time and space simply do not apply in the broader vastness of the universe.

Even having learned this in similar works, I still cannot get over the craziness of it. As Rovelli writes, “On Earth gravity is more or less the same everywhere... This is not the case in the wider universe. Time passes at different speeds for different travelers: when they meet again, they have generally not aged by the same number of years." Equally eerie is how general relativity describes reality as a set of fields that define spatial extension and time themselves, rather than sitting inside them. As he notes, "The location of an event only makes sense in relation to others. There is no 'where' or 'when,' except in a relative sense.”

While the book does discuss theories and their relationships, I found that as it progresses, it primarily makes a case for Rovelli's personal stances on how much value should be placed on each. I was interested in his perspectives on the flow of time and whether the future is open or fixed. However, I lacked the background in the intricacies of many other theories to fully engage with his arguments. Readers with a deeper understanding of physics will appreciate these perspectives, but I was hoping for more instruction on actual physics rather than debates on nuanced details. Even so, it successfully opened my eyes to what is important to consider so as not to fall into the trap of hyped-up theories pertaining to the flow of time and the Observer Effect.

Due to this, I found the concluding paragraph in lesson 5 gives a better synopsis of the book's true heart than the publisher's summary: “The reasonable question, it seems to me, is to ask what, given the current state of our knowledge... are effective concepts for thinking about the world, accounting for it, and navigating it?... Things all exist equally, in relation to others, each in its own way — a way that evolves as we learn.”

I highly recommend picking up this book if you have a foundation in physics and philosophy and want to engage in a discussion about the importance of certain areas of the field. The detailed footnotes are also a major benefit for those looking for a heavily researched work. I will certainly be picking up more of Rovelli's books.

Read more of my book reviews here...
https://fortandfield.blogspot.com/202...

[Mark Schlack · Rating 5 out of 5]

Rovelli remains one of the most compelling thinkers and writers in the science community. In addition to being a world-class theoretical physicist, he is keenly interested in philosophy and art and how they intersect with and influenced/are influenced by science. In this book, Rovelli weighs in on the big picture: what we have learned in the last 100 years and how that might upend long-held views about the nature of reality and the workings of the universe.

The main point that Rovelli makes in this book is that there are no absolutes in the universe. Time and space are relative, as Einstein established. How you experience them depends on your context -- there is no fixed clock in the universe, nor some fixed point from which you can measure things. He takes further aim at Western science tradition by dismissing the Aristotelian notion of essence, that things have an essential quality that we can know. Closely related is the idea that we can know the nature of things by knowing what their fundamental composition is: we can know matter through subatomic particles, for example. In Rovelli's view, all we can know about anything comes from observing how it interacts with other things. So reality is not only relative, but relational.

You may not agree with Rovelli but this book will give you an eloquent statement of a new spirit emerging among contemporary scientists that goes beyond the specifics of loop quantum gravity (his pet theory). It's a theory that seeks to rebalance science as more than just equations and to credit experience as providing valid insights. If you read The Blind Spot, you'll appreciate someone who harmonizes with some of that. And is far clearer and concise in expressing those ideas.

If you read no other book about the state of modern science this year, read this one. It will resonate for years to come.

[Luc Verheyen · Rating 4 out of 5]

'Het is een vreemde wereld. Maar voor ons, voornamelijk uit gedachten en gevoelens bestaande sterfelijke wezens, lijkt ze mij tamelijk gemakkelijk toegankelijk en aangenaam.'

'De wereld omvat ons, die haar gedeeltelijk kennen, en de wereld waarover we spreken is datgene wat we van de wereld kennen. Het is de gelukkige cirkel waarvan wij deel uitmaken.'

'Wij zelf zijn in de tijd bestaande wezens.(...) We zouden niet gedurende één enkel ogenblik kunnen bestaan: wij zijn de eersten die geen entiteiten zijn, maar juist processen.(...) De tijdgeoriënteerd van het kennisproces ligt ten grondslag aan het krachtige gevoel van het verstrijken van de tijd dat wij ervaren: wij zijn zelf tijdgeoriënteerde fenomenen.(...) Het is ons denken dat voortsnelt, niet de tijd.'

'De wereld zoals we die kennen laat toe dat ze wordt beschreven van binnenuit, we leren haar van binnenuit kennen, we treden er nooit buiten.(...) De waarheid over de toestand van de wereld is, in deze zin, een subjectieve waarheid.'

'De subtiliteit van de Natuur overstijgt verre de subtiliteit van de zintuigen en het intellect: dus zijn de subtiele overpeinzingen, speculaties en redeneringen van de mensen een soort dwaasheid, maar er is alleen niemand die dat kan opmerken. - Francis Bacon. Novum Organum, I, 10.'

'Denk niet, neem waar!'

[Kakul · Rating 4.75 out of 5]

“The world is always described from within”. This is what Carlo Rovelli beautifully synthesizes in his gorgeous meditation on physics and philosophy: There is no unified reality, it’s merely a dance of perspectives from the inside.

You might be tempted to think this is reductionist, but to me this was such an expansive way to look at our lives - there is no one unified reality for a physicist, chemist, Buddhist, or mechanic; they are all at once true and incomplete.

In 6 lessons, most of which are as dense as they are fascinating, @carlitorovelli packs in aspects of the universe, the concept of spacetime, circularity, gravity, Nagarjuna (the Indian Mahayana Buddhism monk from the 2nd century), and Kierkegaard, and how all of these speak to each other. My favourite lesson was on the flow of time (anyone who knows me could’ve guessed this), which seems to move from past to present only because “as dissipative phenomena who deliberate our actions by considering possible futures, it is our thinking that runs forward, not time.”
And how it is our very humanity that gives time its texture, anxiety, hope, worry, its very “temporality,” and how without us time would still exist, but sparser.

So (hopefully) you’ll find like I did, that there are many ways to understand a world and a life, but none beat truly immersing yourself in it and experiencing it.

[Jonathan Van der horst · Rating 4 out of 5]

‘Is it really, really real? Yeah / Wе're splitting up reality / And I slip out through the crack in bеtween it / Is it really real?’, zingt popster Robyn in een nummer op haar laatste album. Een tekst die vermoedelijk over de zoveelste tragische liefdesrelatie gaat, maar na het lezen van Helgoland van Carlo Rovelli, begon ik toch te twijfelen of Robyn zich niet ook stiekem een beetje in de kwantumfysica heeft verdiept. Met het werk van Rovelli zou dat in ieder geval goed mogelijk moeten zijn. Deze theoretisch natuurkundige van beroep maakt namelijk al een tijdlang furore met boeken waarin hij de ideeën van de moderne fysica zo kort en krachtig uit de doeken doet dat ze zelfs voor een gemiddelde popster te begrijpen zouden moeten zijn.

De rest van deze recensie is te lezen op Tzum of op mijn Substack

[Elisa · Rating 4 out of 5]

Rovelli has a remarkable ability to make even the most challenging subjects accessible to general readers, and this short volume is no exception. Blending physics, philosophy, and history, he explores key concepts and weaves them together into a coherent and thought-provoking narrative. He even offers an accessible explanation of how the Standard Model and quantum mechanics relate to one another.
My own knowledge of physics is limited, but Rovelli's use of clear, well-chosen examples helped me grasp ideas without oversimplifying them. In his exploration of the universe, he even finds room to consider the concept of God. Despite its brevity, this is not a book to rush through; its ideas are best appreciated by taking the time to pause and reflect on them.
I chose to read this book and all opinions in this review are my own and completely unbiased. Thank you, NetGalley/Scribner.

[K— H.]

Felt like I should be reading this in tandem with a philosophical work providing the opposing arguments. I think due to Rovelli’s general popularity the dynamics of this didn’t make a lot of sense, kind of like if you had argument with your friend, then blared your side all over social media. Instead, it should be treated almost as a memoir; here is how Rovelli has learned to understand the world. He loves Zhuangzi and Ludwig Wittgenstein, for example.

I think actually reading some of Rovelli’s other works would have helped prepare me for this. The center of the book was particularly difficult to follow. However, I have been musing on the relationality of the world, thanks to Lefebvre’s The Production of Space, and so many of the arguments resonated with me, even when the technicality or criticality of philosophy (and modern-day physics) did not always do the same.

[Justin Tully · Rating 5 out of 5]

Carlo Rovelli has been called a modern day poet of physics. His well established and revered life’s work has explored the edges of everything we know about nature. In this book he shares with us his most lucid, far reaching, and yet familiar to all, perspective that a life at the bitter edge has shown to him; the only thing that matters, is connection. And everyTHING, and nonTHING, that together manifest the world around us only take on meaning through their vast and thorough interconnectedness. From the starting line of hard core science, we arrive at vistas visited and told about millennia ago by indigenous spiritual leaders, yogis, and medicine women. We are all one.

[Giuseppe · Rating 3 out of 5]

I've read 3 or 4 books by Rovelli before and I liked them a lot, this one not as much.
It's not as focused as other works, he's usually good at embellishing the main topic with historical or philosophical digressions, but on this one, he goes into a bunch of topics without connecting them too clearly. He often tries to force his philosophical views, dismissing other ideas or questions as wrong, meaningless, etc.
There are some thought-provoking reflections and interesting moments, but Rovelli here tries to be a philosopher without having, in my opinion, enough depth to pull it off well

[Rehan Naqvi · Rating 3 out of 5]

> I am sympathetic to relational view, disembodied knowledge, and perpectivism.

Few big issues:

> Rovelli accused his opponents of assigning ideological and religous biases to physical world. But isn't Rovelli suffering from same bias, he lets his political left view in which everything is equal to be applied to physical world.

> Very poor understanding of moral philosophy. No idea what he is trying to say. Same is the case with consciousness. Not any concrete reason given how it is physical? How it is subtitute for "communication" between people?

[Brian Hanson · Rating 3 out of 5]

Scientists are scathing - often but not always with reason - about, say, Christians who exploit the mysteries of quantum physics to bring God back into the story. But what about scientists who use that physics to smuggle in their own ideologies? Rovelli is a captivating writer, justly praised for his talent for popularisation without over-simplification. However, as I've said before, his "relational" approach thinly-disguises his Marxist Weltanschauung ("all that is solid melts into air") - which becomes particularly evident in a book like this, which extends the science into philosophy.

[Mick Beaman · Rating 4 out of 5]

I get the basic underlying ideas and the concepts, but simply can't understand the application to the world of quantum theory and time as he describes it. A lot seems to be presented as self evident although mitigation, there are some health warnings at the outset.
By way of context, because it's relevant in reviewing technical books of this sort, I have no background in the sciences, but do have a postgraduate degree, so assume i'm not just totally thick.

[James Easterson · Rating 4.25 out of 5]

I didn’t understand or follow everything, some of it I felt due to his own semantics, some of it complex words and concepts, I hate footnotes, he could be a better writer, but I’ve learned a ton and agree with him perhaps completely! Carlo Rovelli has always been the one physicists leading me through the quantum maze.
Another book I’d recommend is : Waves in an Impossible Sea: How Everyday Life Emerges from the
Cosmic Ocean by Matt Strassler

[Charlotte · Rating 4 out of 5]

A take-away from this book: ignore the contemporary American students of philosophy for the sake of your own blood pressure. XD

Giving it a 4 for now; a very easy and engaging read which I swallowed probably a bit too fast. Short, clear, cheeky, full worth re-reading, and lightly sprinkled with formulas for taste.

[Josh Clausen · Rating 4 out of 5]

There is no doubt Rovelli is one of my favorite authors & this one is right up there with his best. A thought-provoking lecture on how “science” and “philosophy” really aren’t but two sides of a norrow-edged coin.

[Michael Bogin · Rating 4 out of 5]

I've read all of Carlo Rovelli's books. This one is a little different and it's among his best. I never understand me then about 20 percent of what he's discussing, but days later I'm still thinking about relativism. That alone makes it worth the read.

[Lambros Kromidas · Rating 2.5 out of 5]

I read all of Carlo Rovelli’s books and couldn’t wait to get and read this one. But I was disappointed. Found it a little verbose and not written for the lay reader who is interested in the explanations of physics. Somewhat esoteric as regards to philosophy.

[Meagan Shay · Rating 4 out of 5]

A brief lesson on quantum physics and what it means for philosophy.

[Lisa Vandebrouck · Rating 3 out of 5]

Interessante visie maar soms wat ontoegankelijk.

[Ell, Ess Jaeva · Rating 1 out of 5]

20%

[Ian · Rating 3.5 out of 5]

“We approach the truth by a series of successive approximations”