Carlo Rovelli Quotes

Here, in the vanguard, beyond the borders of knowledge, science becomes even more beautiful - incandescent in the forge of nascent ideas, of intuitions, of attempts. Of roads taken and then abandoned, of enthusiasms. In the effort to imagine what has not yet been imagined. Twenty

We never really see time. We see only clocks. If you say this object moves, what you really mean is that this object is here when the hand of your clock is here, and so on. We say we measure time with clocks, but we see only the hands of the clocks, not time itself. And the hands of a clock are a physical variable like any other. So in a sense we cheat because what we really observe are physical variables as a function of other physical variables, but we represent that as if everything is evolving in time.

The primal substance of our thoughts is an extremely rich gathering of information that's accumulated, exchanged, and continually elaborated. Even

the particles are quanta of quantum fields; light is formed by quanta of a field; space is nothing more than a field, which is also made of quanta; and time emerges from the processes of this same field. In other words, the world is made entirely from quantum fields (

To the very last, the desire to challenge oneself and understand more. And to the very last: doubt.

We understand the world in its becoming, not in its being.

I think that the obscurity of the theory is not the fault of quantum mechanics but is rather due to the limited capacity of our imagination. When we try to "see" the quantum world, we are rather like moles used to living underground, to whom someone is trying to describe the Himalayas. Or like the men imprisoned at the back of Plato's cave.

The difference between past and future exists only when there is heat. The fundamental phenomenon that distinguishes the future from the past is the fact that heat passes from things that are hotter to things that are colder. So,

if nothing else around it changes, heat cannot pass from a cold body to a hot one......This is the only basic law of physics that distinguishes the past from the future.

due to the limitations of our consciousness we perceive only a blurred vision of the world and live in time.

Things change only in relation to one another. At a fundamental level, there is no time.

The entropy of the world in the far past appears very low to us. But this might not reflect the exact state of the world: it might regard the subset of the world' s variables with which we, as physical systems, have interacted. It is with respect to the dramatic blurring produced by our interactions with the world, caused by the small set of macroscopic variables in terms of which we describe the world, that the entropy of the universe was low.

The world is like a collection of interrelated points of view.

The world of quantum mechanics is not a world of objects: it is a world of events.

Physics does not describe how things evolve "in time" but how things evolve in their own times, and how "times" evolve relative to each other.

Listening a cultivated person of today that jokes and almost boasts about his scientific ignorance, is as sad as listening a scientist that boasts about not having read any poem.

Quantum mechanics extends this relativity in a radical way: all variable aspects of an object exist only in relation to other objects. It is only in interactions that nature draws the world.

The passage of time is internal to the world, is born in the world itself in the relationship between quantum events that comprise the world and are themselves the source of time. The

But this does not imply that we cannot or must not trust our own thinking. To the contrary: our own thinking is the best tool we have for finding our way in this world. Recognizing its limitations does not imply that it is not something to rely upon. If instead we trust in "tradition" more than in our own thinking, for instance, we are only relying on something even more primitive and uncertain than our own thinking. "Tradition" is nothing else than the codified thinking of human beings who lived at times when ignorance was even greater than ours.

Albert [Einstein] was reading Kant and attending occasional lectures at the University of Pavia: for pleasure, without being registered there or having to think about exams. It is thus that serious scientists are made.

Clues put us on the right path toward a correct theory. Strong evidence is that which subsequently allows us to trust whether the theory we have built is a good one or not. Without

In the awareness that we can always be wrong, and therefore ready at any moment to change direction if a new track appears; but knowing also that if we are good enough we will get it right and will find what we are seeking. This is the nature of science. The

The world is complex, and we capture it with different languages, each appropriate to the process that we are describing.

If we try to put together what we have learned in the twentieth century about the physical world, the clues point toward something profoundly different from our instinctive understanding of matter, space, and time.

The heat of black holes is like the Rosetta stone of physics, written in a combination of three languages- quantum, gravitational, and thermodynamic- still awaiting decipherment in order to reveal the true nature of time.

Because science shows us how to better understand the world, but it also reveals to us just how vast is the extent of what is still not known. The

It is not against nature to be curious: it is our nature to be so.

An idea was needed, a great idea, a grand vision, to grasp the hidden order of the world. Leucippus and Democritus came up with this idea. The idea of Democritus's system is extremely simple: the entire universe is made up of a boundless space in which innumerable atoms run. Space is without limits; has neither an above nor a below; is without a center or a boundary. Atoms have no qualities at all, apart from their shape. They

This does not mean that science is just the art of making measurable predictions. Some philosophers of science overly circumscribe science by limiting it to its numerical predictions. They miss the point, because they confuse the instruments with the objectives. Verifiable quantitative predictions are instruments to validate hypotheses. The objective of scientific research is not just to arrive at predictions: it is to understand how the world functions; to construct and develop an image of the world, a conceptual structure to enable us to think about. Before being technical, science is visionary.

Compare 'now' with 'here'. 'Here' designates the place where a speaker is: for two different people 'here' points to two different places. Consequently 'here' is a word the meaning of which depends on where it is spoken. The technical term for this kind of utterance is 'indexical'. 'Now' also points to the instant in which the word is uttered and is also classed as 'indexical'. But no one would dream of saying that things 'here' exist, whereas things that are not 'here' do not exist. So then why do we say that things that are 'now' exist and that everything else doesn't?

Without clues, we search in the wrong directions. Without evidence, a theory is not reliable.

Science begins with a vision".

Nature is behaving with us like that elderly rabbi to whom two men went in order to settle a dispute. Having listened to the first, the rabbi says: "You are in the right." The second insists on being heard. The rabbi listens to him and says: "You're also right." Having overheard from the next room, the rabbi's wife then calls out, "But they can't both be in the right!" The rabbi reflects and nods before concluding: "And you're right too." A

Rationality and the instinct of collaboration have already given us large regions and long periods of peace and prosperity. Ultimately, they will lead us to a planet without countries, without wars, without patriotism, without religions, without poverty, where we will be able to share the world. Actually, maybe I am not sure I truly believe that I believe this, but I do want to believe that I believe this.

as Lucretius wrote: "our appetite for life is voracious, our thirst for life insatiable

we are all born from the same celestial seed; all of us have the same father, from which the earth, the mother who feeds us, receives clear drops of rain, producing from them bright wheat and lush trees, and the human race, and the species of beasts, offering up the foods with which all bodies are nourished, to lead a sweet life and generate offspring

To ask oneself in general what exists or what is real means only to ask how would you like to use a verb and an adjective; it's a grammatical question, not a question about nature. Nature, for its part, is what it is, and we discover it very gradually. If our grammar and our intuition do not readily adapt to what we discover, well, too bad. We must seek to adapt them.

Time is information we don't have. Time is our ignorance.

Time sits at the center of the tangle of problems raised by the intersection of gravity, quantum mechanics, and thermodynamics.

When we seek a sure foundation on which to base decisions about our actions and thoughts, we find that a sure foundation does not exist. We do not even know whether we actually need such a foundation. We continue to make use of vague, uncertain ideas, precisely in those areas that most deeply concern us. What we call "irrational" is the code name for what we don't understand well about ourselves given the limits of our own intelligence.

We are stories, contained within the twenty complicated centimeters behind our eyes...

For everything that moves, time passes more slowly.

We have a hundred billion neurons in our brains, as many as there are stars in a galaxy, with an even more astronomical number of links and potential combinations through which they can interact. We are not conscious of all of this. "We" are the process formed by this entire intricacy, not just by the little of it of which we are conscious.

In his youth Albert Einstein spent a year loafing aimlessly. You don't get anywhere by not 'wasting' time- something, unfortunately, that the parents of teenagers tend frequently to forget.

The present is like the flatness of Earth: an illusion. We

The very foundation of science is to keep the door open to doubt.

The confusion between these two diverse human activities - inventing stories and following traces in order to find something - is the origin of the incomprehension and distrust of science shown by a significant part of our contemporary culture. The separation is a subtle one: the antelope hunted at dawn is not far removed from the antelope deity in that night's storytelling. The

The atoms of our body, as well, flow in and away from us. We, like waves and like all objects, are a flux of events; we are processes, for a brief time monotonous

We are made of the same stardust of which all things are made, and when we are immersed in suffering or when we are experiencing intense joy we are being nothing other than what we can't help but be: a part of our world.

Being aware that we may be wrong is different from claiming that it is senseless to speak of right and wrong. Recognizing diversity and taking seriously ideas that diverge from our own is different from claiming that all ideas are equally worthy. Knowing that a given judgment is born within a complex cultural context and is related to many others does not necessarily imply that we are unable to recognize it is wrong.

I think that the resistance against Darwin is not just the difficulty of seeing the power of a spectacularly beautiful explanation: it is the fear of realizing the extraordinary power that such an explanation has in shattering rests of old world views.

The most credible answers are the ones given by science, because science IS the search for the most credible answers available, not for answers pretending to certainty.

The new coherent picture is not yet available. With all their immense empirical success, G(eneral)R(elativity) and Q(uantum)M(echanics) have left us with an understanding of the physical world which is unclear and badly fragmented. At the foundations of physics there is today confusion and incoherence.

Change is ubiquitous. Only: elementary processes cannot be ordered along a common succession of instants. At the extremely small scale of the quanta of space, the dance of nature does not develop to the rhythm kept by the baton of a single orchestral conductor: every process dances independently with its neighbours, following its own rhythm. The passing of time is intrinsic to the world, it is born of the world itself, out of the relations between quantum events which are the world and which themselves generate their own time.

We are perhaps the only species on Earth to be conscious of the inevitability of our individual mortality. I fear that soon we shall also have to become the only species that will knowingly watch the coming of its own collective demise, or at least the demise of its civilization.

The "present" does not exist in an objective sense any more than "here" exists objectively, but the microscopic interactions within the world prompt the emergence of temporal phenomena within a system (for instance, ourselves) that interacts only through the medium of a myriad of variables. Our

Einstein's 1905 paper came out and suddenly changed people's thinking about space-time. We're again in the middle of something like that. When the dust settles, time - whatever it may be - could turn out to be even stranger and more illusory than even Einstein could imagine.

In quantum mechanics no object has a definite position, except when colliding headlong with something else.

Here, on the edge of what we know, in contact with the ocean of the unknown, shines the mystery and beauty of the world. And it's breathtaking.

Every cubic centimeter of space, and every second that passes, is the result of this dancing foam of extremely small quanta.

What role do we have as human beings who perceive, make decisions, laugh, and cry, in this great fresco of the world as depicted by contemporary physics?

The final section of the book returns to ourselves and asks how it is possible to think about our existence in the light of the strange world described by physics. The

Our intuitions have developed on the basis of our limited experience.

When we talk about the big bang or the fabric of space, what we are doing is not a continuation of the free and fantastic stories that humans have told nightly around campfires for hundreds of thousands of years. It is the continuation of something else: of the gaze of those same men in the first light of day looking at tracks left by antelope in the dust of the savannah - scrutinising and deducting from the details of reality in order to pursue something that we can't see directly but can follow the traces of. In the awareness that we can always be wrong, and therefore ready at any moment to change direction if a new track appears; but knowing also that if we are good enough we will get it right and will find what we are seeking. That is the nature of science.

I remember a little girl...
But how can that be...
Once I was that little Resi,
and then one day I became an old woman?
...If God wills it so, why allow me to see it?
Why doesn't he hide it from me?
Everything is a mystery, such a deep mystery...
I feel the fragility of things in time.
From the bottom of my heart, I feel we should
cling to nothing.

Everything slips through our fingers.
All that we seek to hold on to dissolves.
Everything vanishes, like mist and dreams...
Time is a strange thing.
When we don't need it, it is nothing.
Then, suddenly, there is nothing else.
It is everywhere around us. Also within us.
It seeps into our faces.

It seeps into the mirror, runs through my temples...
Between you and I it runs silently, like an hourglass.
Oh, Quin Quin.
Sometimes I feel it flowing inexorably.
Sometimes I get up in the middle of the night
and stop all the clocks...

We are made up of the same atoms and the same light signals as are exchanged between pine trees in the mountains and stars in the galaxies.

what does it mean, our being free to make decisions, if our behavior does nothing but follow the predetermined laws of nature?

What opens our minds and shows the limits of our ideas is an encounter with other people, other cultures, other ideas.

Time opens up our limited access to the world. Time, then, is the form in which we beings, whose brains are made up essentially of memory and foresight, interact with the world: it is the source of identity.

Perhaps it is we who have not yet learned to look at it from just the right point of view, one that would reveal its hidden simplicity.

To trust immediate intuitions rather than collective examination that is rational, careful, and intelligent is not wisdom: it is the presumption of an old man who refuses to believe that the great world outside his village is any different from the one that he has always known. As

The quanta of gravity, that is, are not in space; they are themselves space. The

Don't trust your teachers.

Within the immense ocean of galaxies and stars we are in a remote corner; amidst the infinite arabesques of forms which constitute reality we are merely a flourish among innumerably many such flourishes.

Space is a spin network whose nodes represent its elementary grains, and whose links describe their proximity relations. Spacetime