The Order of Time

In The Order of Time (2018), a work of philosophical science, Carlo Rovelli explores the meaning of time, proposing that time is an illusion shaped by our own personal realities rather than any natural or scientific law. An Italian theoretical physicist responsible for developing the loop quantum gravity theory, Foreign Policy named Rovelli one of the world’s 100 most influential global thinkers; scientists dub him “the new Stephen Hawking.” He is best known for his poetic writing style and for making complex scientific topics accessible to general readers.

The Order of Time proposes that reality and time work very differently from how we imagine they work. Time is only an illusion. Rovelli compares time to planet Earth—although we perceive the Earth as flat because it looks flat as we walk and drive around it, the Earth is spherical. It is not as we perceive it.

What makes time different from Earth, however, is that we know what Earth really looks like. No one can definitively say how time works, but that should not stop us from trying to make sense of it. For Rovelli, the first step toward understanding how time works is accepting that we know nothing about it.



Rovelli divides The Order of Time into three parts: “The Crumbling of Time,” “The World Without Time,” and “The Sources of Time.” In the first section, he summarizes how we have lost our sense of time. The second section looks at a world without time, and the third part considers why our ancestors created the concept of time in the first place.

In “The Crumbling of Time,” Rovelli argues that the more we try to understand time, the less sense it makes. For example, we think that time passes everywhere at the same speed, but this is not true. A clock, for example, moves faster or slower depending on whether it is on a flat surface or on the ground. It moves faster at higher altitudes than lower altitudes, so theoretically, people at higher altitudes live “longer” than people at sea level.

There is no such thing as the present, or the now. What we think of as the present is already in the past. There are two reasons for this. First, it takes time for light to travel—so, for example, when we watch a sunset, we are seeing what happened almost 10 minutes earlier. Second, it takes time, even if it is just a few seconds, for our minds to process our surroundings. Our understanding of the present, then, is wrong.



In part two, Rovelli considers what the world looks like once we remove time from the equation. The world is a collection of events, not things. For example, rocks are not things. Forces, matter, and vibrations clash to form stones. They clash in such a way that the stone holds its shape for years, decades, or longer. However, the stone turns to dust eventually.

Another example, a kiss may only last a few seconds, but it is the same as a stone in natural terms—it is simply a much shorter event than a stone’s lifespan. Rovelli appreciates that it is difficult to comprehend this because the vocabulary does not exist for us to express it properly. All we know is the past, present, and future, and we talk about objects as things rather than long or short temporal events. Until linguistics catches up with science, it is impossible for us to talk about natural law in a meaningful way that resonates with us.

In the third section, “The Sources of Time,” Rovelli considers why we constructed time in a world where there is no such thing as time. He also questions why we created the system we have instead of devising a different system. In short, we need time to make sense of the universe. Without time, nothing exists; it is difficult to live our lives that way.



There is, however, a scientific explanation for why we have constructed time the way we have. If we lived somewhere else in the universe, there might be no reason to construct time. It all comes down to our place in the universe, how matter changes, and the laws of thermodynamics.

Put simply, the past, the present, and the future exist because hot things cool down. In other words, matter changes state. For example, a cup of coffee turns cold eventually although it began hot. In some parts of the universe, this doesn’t happen. Nothing changes; it is hot or cold all the time.

Because matter changes state, we have evolution. Things grow, fade, and evolve. Time as we know it allows us to separate life into the before, now, and after, or the past, present, and future. Rovelli encourages us to embrace time because it is the best way to make sense of our natural world but to remember that it is an imperfect illusion, not a natural law.