Carlo Rovelli takes us along on his life’s journey trying to come to conclusions about the nature of reality, the physical world, and the mind. The book starts with an account of the early years of quantum mechanics, the major players, their original motivation and inspiration. While the predictions of quantum mechanics have been confirmed time and time again, the theory has shattered our metaphysical belief in a reality made up of particles that move along defined trajectories. What should we make of this? Rovelli briefly discusses various pictures of reality painted by several proposed interpretations of quantum mechanics, but ultimately dismisses them all as unsatisfactory. His real focus is on the “relational” interpretation, freed from metaphysical assumptions. The relational perspective assumes that the world we observe is (nothing but) a dense web of interactions. A reality made up of relations rather than objects (p. xvi), where facts are relative rather than absolute. Things exist in context. Next: Did you know Lenin and a less well-known Marxist named Aleksandr Bogdanov argued about Mach’s “empiriocriticism”? I didn’t, and Rovelli’s account of the cultural influences preceeding the discovery of quantum theory is fascinating. The remainder of the book explores how a relational perspective of the physical world can impact our understanding of meaning and consciousness. It is mostly this last part that I am concerned with in the following.
Why discuss this book?
The book is a quick and delightful read. I very much enjoyed the history of science part, as well as the perspective the book provides on the cultural influences preceeding quantum mechanics, which anticipated the take down of an absolute reality by quantum physics. Personally, I had hoped that this book would provide me with a better understanding of the mysteries of quantum mechanics and how Rovelli’s perspective might shed light on quantum weirdness. In that respect, I didn’t find what I was looking for. Rather than clarifying how a relational interpretation can account for quantum observations, the book is a meditation on a world made up of relations, without any metaphysical fundament to ground it. In a way, the book itself is a relational account of its author and his many interests that are tied together in sometimes surprising ways on a path towards insight. Ultimately, “Helgoland” remains light, almost ephemeral in its conclusions. The book draws connections between information, evolution, meaning, consciousness, quantum mechanics, “samsa̅ra”, and socialist political philosophy. Regarding the relational interpretation, I must admit that I could have done with a bit more substance (pun intended). And yet, Rovelli’s worldview resonates with my own intuitions—and the assumptions behind integrated information theory (IIT)—to a remarkable degree. It is those passages that I want to highlight and discuss below. Rather than a conclusion, the book provides a starting point, one that should be taken more seriously and promoted more widely.
What does consciousness have to do with quantum mechanics, or the other way around? Neither my, nor Rovelli’s goal is to account for consciousness through quantum mechanics (p. 161). And yet, if we want to gain insights on how consciousness fits into our conception of the physical world, it matters what we believe this world to be.
As Rovelli says, “if […] the world is better described in terms of relations, if nothing has intrinsic properties except in relation to other things, perhaps in this physics we can better find elements able to combine […] to be the basis of […] consciousness.” (p. 164). In such a world “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.” (p. 165) This is awfully close in spirit to IIT!
Take IIT’s 0th postulate or “principle of being”: to exist physically means to have cause-effect power—being able to take and make a difference. In other words, physical existence is defined purely operationally, from the extrinsic perspective of a conscious observer, with no residual “intrinsic” properties (such as mass or charge) (from “Only what exists can cause: an intrinsic view of free will (Tononi et al., 2022)).
Both IIT and Rovelli (p. 145) refer to the Eleatic principle as an ancient expression of a relational, causal definition of what it means to exist. Here is Rovelli: “Individual objects are the way in which they interact. If there was an object that had no interactions, […] it would be as good as nonexistent. […] It is not even clear what it would mean to say that such objects ‘exist’.” (p. 76)
For Rovelli, quantum theory is a manifestation of a relational reality. He writes: “The discovery of quantum theory, I believe, is the discovery that the properties of any entity are nothing other than the way in which that entity influences others.” (p. 77) “Quantum theory invites us to see the physical world as a net of relations. Objects are its nodes.” (p. 79)
In IIT, we describe (simplified models of) the physical world by a transition probability matrix (TPM) that reflects the conditional probability of how the state of every elementary unit responds to the state of any other unit. A TPM can be deterministic or probabilistic, and there are reasons to think it should be probabilistic at the bottom that arise from within IIT (Tononi et al., 2022). Nevertheless, IIT’s TPMs, while relational, still correspond to a classical picture of reality (albeit one with indeterminism).
To account for quantum phenomena, Rovelli posits an additional aspect of the relational view: “Facts that are real with respect to an object are not necessarily so with respect to another.” (p. 81) While “it is possible to think of quantum physics as a theory of [relative] information” (p. 103), this information takes a weird shape: it is finite, but at the same time it is always possible to obtain more of it (p. 104).
What shape and form do interactions between objects take in Rovelli’s picture? Here is what I gathered: “The ‘quantum state’ \(\psi\) is always a relative state.” (p. 83) In the classical picture of IIT (and even the quantum extension I am working on), there is still an absolute (but possibly mixed) state associated with a set of units. Unfortunately (for me), “Helgoland” is rather light on the formal workings of the relational interpretation of quantum physics. I guess I will have to check the primary literature.
Here are a few more hints: “The relational perspective takes the theory [QM] as is […] with its sketchy description of the world, and accepts indeterminacy, as QBism does. But while QBism is about the information of a subject, the relational understanding of quantum theory is about the structure of the world.” (p. 87), and then there is a footnote on p. 81.
[Footnote p. 81: “The problem with quantum mechanics is the apparent contradictions between two laws of the theory: one describes what happens in a ‘measurement,’’ and the other in the ‘unitary’ evolution, namely when there is no measurement. The relational interpretation is the idea that both are correct: the first regards the events relative to the system in interaction, the second regards the events relative to other systems.”]
“An object does not have one \(\psi\) wave, it has one with respect to every other object with which it interacts. Events that take place in relation to one thing do not influence the probability of events that occur in relation to others.” (p. 83) And yet, “there is method in this madness” (p. 100) While properties are relative, they still end up being consistent. I will have to see what that really means.
For now, let’s turn our attention back to consciousness. If everything is relational, what are we left with? Rovelli’s answer: Nothing, really. Chairs, for instance, only exist in relation to us (p. 145). “The world is not divided into stand-alone entities.” (p. 146). And also the “I”, the self or “ego”, does not exist. Everything is empty, an illusion, nonexistent—“samsa̅ra”. (Here, Rovelli took much inspiration from the Buddhist philosopher Na̅ga̅rjuna. I haven’t read Na̅ga̅rjuna’s work myself, so I will rely on Rovelli’s account only.)
Now I don’t know about Carlo, but I certainly exist. Not as a persistent self, not as a process extended in time—so far, I’m with Rovelli. But at every instance that I experience, there is existence. There is something rather than nothing. There may not be an “I” in the colloquial meaning, but there is subjective experience. This subjective experience is unified, and it is bounded, it has a specific content, not more and not less. By a good inference, I can assume that there are other conscious entities but my own. My experience is thus evidence that there are, in fact, (interacting, but still) stand-alone entities, and we have to account for that if we want to arrive at a complete picture of the natural world (Ellia et al., 2020).
Rovelli rejects Ernst Mach’s proposal of assuming “elements and functions” as fundamental (p. 149), as well as any kind of proto-consciousness pan-psychism based on intrinsic qualities (p. 164). Fine with me. By contrast, what IIT offers, is a way to obtain entities that exist, intrinsically, for themselves, out of a physical substrate that is purely operational. While objects exist only in relation to others, subjects exist in relation to themselves. If we can agree on a definition of existence as interaction, or cause-effect power, a system exists for itself if it has cause-effect power onto itself (above a background of external interactions).
Rovelli writes: “what quantum theory describes, then, is the way in which one part of nature manifests itself to any other single part of nature.” (p. 75). This is a beautiful notion and really captures the essence of consciousness according to IIT—if we turn it onto itself: consciousness is the way in which a part of nature manifests itself to itself. “The rigid distinction between a mental world and a physical one fades.” (p. 165) As Rovelli points out, such a view is neither dualism, idealism, nor (naive) materialism (p. 183), but really offers a different perspective on the mind-body problem (which also explains why IIT resists attempts to be pressed into any of these categories, and I would include functionalism in that list.)
While I see great potential in combining a relational picture of quantum physics with the ideas of IIT, Rovelli’s reflection on meaning and consciousness go into a different direction. The reason, I believe, is that his primary objective is to capture intentionality, the notion that our mental states or processes refer to something “outside”. In broad strokes, Rovelli attempts to pair relative information (correlation), with evolution, to obtain a notion of “relevant relative information” (p. 173). While this strikes me as a useful notion in a biological context, it falls short of connecting to consciousness. The reason is that “relevant relative information” remains an extrinsic quantity.
[Rovelli presented these ideas in a prize-winning fQXi essay titled “Meaning and Intentionality = Information + Evolution”. Rovelli shared the first prize with, guess who … yours truly (and a third essayist, Jochen Szangolies). I only mention this here (!), because my essay on intrinsic information is also a reply to Rovelli’s, outlining the difference between extrinsic and intrinsic meaning.]
As Rovelli emphasizes several times throughout the book, a correlation between two objects only manifests itself with respect to a third object interacting with both. “That two objects (the sky and you) have relative information is hence, in the final analysis, something that regards a third object (me observing you). Relative information, remember, is a dance for three, like entanglement.” (p. 177) But here is the problem: while your eyes might have sensors that react to a certain frequency of light, no other part of your brain has direct information about the sky. There is no third object within the brain that can observe the correlation with something outside and your sensors. Rovelli mentions the possibility of a “correlation between the external world and my memory.” But nothing in the brain (leaving out the sensory neurons in the retina) can actually assess such a correlation. Our intrinsic meaning, seeing (experiencing) the blue sky, is not explainable by a correlation between the actual sky and the brain. It must arise solely from the interactions within our brain. We can see blue skies in our dreams, even if it is dark outside.
The notion of relevant relative information is certainly useful with respect to the question how our brain evolved and developed to be connected the way it is. But once we have a functioning brain, it is only internal interactions that we can rely on to account for our experiences. While Rovelli recognizes the dream-like character of our waking experiences (p. 194), the predictive coding view he advertises in the final section of the book does not provide a solution to the problem of intrinsic meaning, nor the problem of identifying conscious systems. (See my review of Anil Seth’s book on that topic.)
“We are such stuff as dreams are made on” (p. 198 from Shakespeare’s The Tempest), but dreams are not ephemeral illusions, they are subjective experiences that exist for themselves.
Rovelli C (2021) Helgoland. Publisher: Riverhead books.