Helgoland: Making Sense of the Quantum Revolution

by Carlo Rovelli

“What are these ‘most rooted metaphysical convictions’ of ours, if not what we have become accustomed to believe precisely by handling stones and pieces of wood?”

Our experience is limited. We cannot take as gospel truth the generalizations that we have made in the past.

“The fact that we live at the bottom of a deep gravity well, on the surface of a gas covered planet going around a nuclear fireball 90 million miles away and think this to be normal is obviously some indication of how skewed our perspective tends to

What we need to add to Bohr’s paragraph is the awareness, which has grown in the course of a century of successes for the theory, of the fact that all nature is quantum,

quantum physics demonstrates that the interaction is an inseparable part of phenomena. The unambiguous description of any phenomenon requires the inclusion of all the objects involved in the interaction in which the phenomenon manifests itself.

“Contextuality” is the technical name that denotes this central aspect of quantum physics: things exist in a context.

The conclusion is revolutionary. It leaps beyond the idea that the world is made up of a substance that has attributes, and forces us to think about everything in terms of relations.

If nothing exists in itself, everything exists only through dependence on something else, in relation to something else. The technical term used by Nāgārjuna to describe the absence of independent existence is “emptiness” (śūnyatā): things are “empty” in the sense of having no autonomous existence. They exist thanks to, as a function of, with respect to, in the perspective of, something else.

“I” is nothing other than the vast and interconnected set of phenomena that constitute it, each one dependent on something else. Centuries of Western speculation on the subject, and on the nature of consciousness, vanish like morning mist.

If every metaphysics seeks a primary substance, an essence on which everything may depend, the point of departure from which everything follows, Nāgārjuna suggests that the ultimate substance, the point of departure . . . does not exist.

The world of phenomena is one that we can investigate, gradually improving our understanding of it. We may find general characteristics. But it is a world of interdependence and contingencies, not a world we should trouble ourselves attempting to derive from an Absolute.

The search for knowledge is not nourished by certainty: it is nourished by a radical absence of certainty. Thanks to the acute awareness of our ignorance, we are open to doubt and can continue to learn and to learn better.

I am not a philosopher, I am a physicist: a simple mechanic. And this simple mechanic, who deals with quanta, is taught by Nāgārjuna that it is possible to think of the manifestations of objects without having to ask what the object is in itself, independent from its manifestations.

But Nāgārjuna’s emptiness also nourishes an ethical stance that clears the sky from the endless disquietude: to understand that we do not exist as autonomous entities helps us free ourselves from attachments and suffering. Precisely because of its impermanence, because of the absence of any absolute, the now has meaning and is precious.

For me as a human being, Nāgārjuna teaches the serenity, the lightness and the shining beauty of the world: we are nothing but images of images. Reality, including our selves, is nothing but a thin and fragile veil, beyond which . . . there is nothing.

The rigid distinction between a mental world and a physical one fades. It is possible to think of both mental and physical phenomena as natural phenomena: both products of interactions between parts of the physical world.

But quantum physics is the discovery that the physical world is a web of correlations: relative information.

Meaning and intentionality are only particular cases of the ubiquity of correlations. There is a continuity between the world of meanings in our mental life and the physical world. Both are relations. The distance between the way we think about the physical world and the way we think about our mental world diminishes.

I close this chapter by mentioning one further way in which the rethinking of reality suggested by quantum theory helps us dispel the myth of a radical difference between the mental world and the physical world.

Who is the “I” that has the sensation of feeling, if not the integrated set of our mental processes? We have an intuition of unity when we think about ourselves, but this is justified by the integration of our body and by the ways our mental processes work, of which the part we call conscious does one thing at a time. The first term of the problem, the “I,” is the residue of a metaphysical error: the result of the common mistake of mistaking a process for an entity. (Mach is categorical: “Das Ego ist unrettbar”: the “I”

If we think in terms of processes, events, in terms of relative properties, of a world of relations, the hiatus between physical phenomena and mental phenomena is much less dramatic. It becomes possible to see both as natural phenomena generated by complex structures of interactions.

The implications for the relationship between what we see and the world, however, are remarkable. When we look around ourselves, we are not truly “observing”: we are instead dreaming an image of the world based on what we know (including bias and misconception) and unconsciously scrutinizing the world to reveal any discrepancies, which, if necessary, we will try to correct.

the words of the nineteenth-century French philosopher Hippolyte Taine, we can say that “external perception is an internal dream which proves to be in harmony with external things; and instead of calling ‘hallucination’ a false perception, we must call external perception ‘a confirmed hallucination.’”

hope that what I have written may contribute to this. The best description of reality that we have found is in terms of events that weave a web of interactions.

“Entities” are nothing other than ephemeral nodes in this web. Their properties are not determined until the moment of these interactions; they exist only in relation to something else. Everything is what it is only with respect to something else.

Every vision is partial. There is no way of seeing reality that is not dependent on a perspective—no point of vie...

It is for this reason, I think, that everything we have been able to accomplish over the centuries has been achieved in a network of exchanges, collaborating. This is why the politics of collaboration is so much more sensible and effective than the politics of competition . . .

The interconnectedness of things, the reflection of one in another, shines with a clear light that the coldness of eighteenth-century mechanism could not capture. Even if it leaves us astonished. Even if it leaves us with a profound sense of mystery.