Reality Is Not What It Seems: The Journey to Quantum Gravity

by Carlo Rovelli

The universe is multiform and boundless, and we continue to stumble upon new aspects of it. The more we learn about the world, the more we are amazed by its variety, beauty, and simplicity.

But the more we discover, the more we understand that what we don’t yet know is greater than what we know.

Science is made up of experiments, hypotheses, equations, calculations, and long discussions; but these are only tools, like the instruments of musicians. In the end, what matters in music is the music itself, and what matters in science is the understanding of the world that science provides.

And the more we understand the world the greater we can appreciate the one who created this “by the Word of His Power” as Colossians says

If we see a child playing on the beach, it is only because between him and ourselves there is this lake of vibrating lines that transport his image to us. Is the world not marvelous?

I’ve always wondered about this. Such a great way to visually present this

We imagined a flat Earth because of the limitations of our senses, because we cannot see much beyond our own noses. Had we lived on an asteroid of a few kilometers in diameter, like Antoine de Saint-Exupéry’s Little Prince, we would have easily realized we were on a sphere. Had our brain and our senses been more precise, had we easily perceived time in nanoseconds, we would never have made up the idea of a “present” extending everywhere.

But it is not only space that curves: time does too. Einstein predicts that time on Earth passes more quickly at higher altitude, and more slowly at lower altitude. This is measured, and also proves to be the case.

The apparent determinism of the macroscopic world is due only to the fact that the microscopic randomness cancels out on average, leaving only fluctuations too minute for us to perceive in everyday life.

Reality is reduced to interaction. Reality is reduced to relation.

As we abandon the idea of space as an inert container, similarly we must abandon the idea of time as an inert flow, along which reality unfurls.

It’s a simple change—but from a conceptual point of view, it’s a huge leap. We must learn to think of the world not as something that changes in time, but in some other way.

The conceptual price paid is the relinquishing of the idea of space, and of time, as general structures within which to frame the world.

For centuries the world has continued to change and expand around us. We see further, understand it better, and are astonished by its variety, by the limitations of the images we had of it. The description we manage to produce to account for it becomes increasingly rarefied, yet simple.