No Thing and Nothing
The other day I came across an interview with theoretical physicist and science writer Carlos Rovelli. He was describing ideas from the relational quantum mechanics theory.
Upon a quick scan, one quote caught my eye: “the world is not a set of things with properties.”
Okay, professor. I’ll bite. What is the world?
“The world is a network of interactions,” he states.
Hmm, so, if there are no things with properties, what’s doing all that interacting?
Well, that’s the thing (or, I guess, the nothing?). There’s only the interacting. Nothing has properties until it interacts with something else.
Pretty Zen, right? Hold onto your hat. You ain’t seen nothing yet. Or, um, maybe you have?
Describing relational quantum mechanics, he states, “The idea is that what quantum theory is teaching us is that we should not think that the properties of something (for instance the kicked ball) are always defined. Rather, properties are just the way something affects something else. So, the ball has literally no properties–not even a position–until it affects something, the glass of the windows, for instance.”
Note the word “literally” here. This left me with oh so many questions, especially when he talks about objects. Can there even be objects? So what is an object?
Turns out an object is “the ensemble of the ways in which it affects other objects around itself. An object exists reflected in everything else.”
Got that? No objects unless they interact with other objects. But if there are no objects to start with, where do the other objects come from?
I know some of this is just the inability of language to capture difficult-to-express ideas about quantum mechanics.
Forced to Read Rovelli (Again)
Once I got to that point in the article point, I knew he had me. I had gone and interacted with his ideas. I could have avoided them. I could have become a human quantum eraser of Rovelli readings.
But no. The ideas and I had interacted and so we both took on properties, I guess. I was then forced to read his next damned book.
Suddenly, thanks to the instant gratification allure of the Kindle, I was reading Hegoland: Making Sense of the Quantum Revolution. After providing a few character sketches of the originators of quantum theory (Heisenberg, Bohr, Jordan and Dirac) and the key contributions of Schrodenger (who disconcertedly turns out to be a pedophile?), Rovelli quickly outlines the basics of quantum theory, jumps into the famously bizarre implications of the double-slit experiment, and briefly outlines various interpretations of quantum theory, with a rhetorical eye on gently undermining them.
But this is all appetizer stuff, preparing readers for the main course: the relational interpretation of quantum physical.
Rovelli’s Wrought Relationships
Let’s back up a sec. What exactly is the relational quantum mechanics (RQM) interpretation of quantum mechanics? Well, look at it like a game of poker.
You remember how Einstein broke broke 19th-century physics when he said the space and time were only relative rather than absolute concepts?
Well, Rovelli ups the ante on the relativity concept, basically going all in. It’s not only time and space that are relative. It’s everything in the whole of creation!
You Are the Eyes of the Universe
A key part of the original idea is that quantum systems are dependent on observers. That is, the state of the system boils down to a relationship between the observer and the heretofore mentioned system.
Confused? Me too.
Are the observers only conscious beings? Are the ball and window observers unto themselves? That is, do the ball and widow become “real” and interact even if I don’t see them do so, or at least see the outcome (that is, the broken window)?
Reality Is Literally Relative
In Hegoland, Rovelli tries to explain his point of view:
What quantum theory describes…is the way in which one part of nature manifests itself to any other single part of nature….The world that we know, that relates to us, that interests us, what we call “reality,” is the vast web of interacting entities, of which we are a part, that manifest themselves by interacting with each other. It is with this web that we are dealing.
One thing he does try to clear up is the role of the observer, saying that “any interaction between two physical objects can be seen as an observation.” So, I guess that we don’t need a person to see the interaction between a ball and window. They are both observers so their interactions make them take on their respective properties.
At least, I think that’s what he’s saying.
But it’s all relative. For you, a fact may be real yet still not be real for me. That’s the real mind-bender in all this.
The fact that some properties exist only with respect to something else should not overly surprise us. We already knew as much. Speed, for example, is a property that an object has relative to another object. Speed does not exist without being anchored (implicitly or explicitly) to something else. It is a relation between two entities. The discovery of quantum theory is only slightly more radical: it is the discovery that all the properties (variables) of all objects are relational, just as in the case of speed.
The Nodes Are the Links?
According to conventional wisdom, networks are made up of nodes and links, with nodes being connecting points joined with other connecting points via those links. Rovelli writes, “Objects are such only with respect to other objects, they are nodes where bridges meet.”
So, in his view, the links between the nodes only exist when the nodes intersect somehow. I think. So….the links don’t exist and then suddenly they do when the nonexistent objects intersect.
Or, something like that…
Part of my confusion is the fact that objects seldom if ever exist in a vacuum. The ball that’s flying toward the window is, as it travels, intersecting with air molecules, photons, water vapor, and so much more. Are all these things “observers” in Rovelli’s conceptualization?
I think so.
If I’ve got this right, it is the intersection of two no-things that causes something to exist. But then he states, “Entanglement is not a dance for two partners, it is a dance for three.”
The Mysterious Third Dancer
Who or what is the third dancer?
It’s what he refers to as a correlation. That is, anytime there is an interaction between two things, there’s a correlation between them, which he also refers to as an entanglement. Is this related to spooky-action-at-a-distance entanglement? He doesn’t say.
Here’s how he defines it: “Entanglement…is none other than the external perspective on the very relations that weave reality: the manifestation of one object to another, in the course of an interaction, in which the properties of the objects become actual.”
So, I see a butterfly and, presto, the butterfly and I are entangled. Our reality is the product of that entanglement. Sure, we may have already been entangled with other stuff. For example, the butterfly may have already been entangled with a flower in my neighbor’s garden and I may have already been entangled with my sneakers (among other things) but the butterfly and I literally don’t exist for one another until there’s an entanglement.
At that point, I guess, my sneakers are entangled with me, which is entangled with the butterfly. Am I entangled with the flower on which the butterfly landed before I saw it? Rovelli leaves me guessing on that score.
Whence Lies Objectivity?
You may be asking yourself, “If the butterfly didn’t exist for you until you interacted with it, then why, once I too have seen the butterfly, do you and I agree on its characteristics?”
He tries to answer it.
If I know that you have looked at the butterfly’s wings, and you tell me that they were blue, I know that if I look at them I will see them as blue: this is what the theory predicts, despite the fact that properties are relative [his emphasis]. The fragmentation of points of view, the multiplicity of perspective opened up by the fact that properties are only relative, is repaired, made coherent, by this consistency, which is an intrinsic part of the grammar of the theory. This consistency is the basis of the intersubjectivity of our communal vision of the world.
The Mind of God
I don’t know how things that don’t exist (or, at least, don’t have properties) can interact with one another. If he explains that, I somehow missed it.
Maybe groups of realities exist (for example, one with a butterfly and a flower and another with myself and my sneakers) in which all the nodes are interacting with one another. Then somebody (let’s say the butterfly) who has been made real in one reality (by virtue of its interactions) is able to interact with somebody (let’s say me) from a separate reality because of some clash between group/interaction-based realities.
Uh-huh. Even I don’t quite know what that means. I think the holes in Rovelli’s narrative leave me guessing.
Are we all just conceits in the mind of God, with no reality of our own?
His ideas also touch on our sense of self. That is, we do not exist in ourselves. Rather, we are made up of a vast reticulum of phenomena, each link and node dependent on others.
Rovelli tries to elucidate further by delving into the ideas of Nāgārjuna, an Indian Mahāyāna Buddhist philosopher who wrote The Fundamental Wisdom of the Middle Way in the second century CE. “The central thesis of Nāgārjuna’s book,” Rovelli writes, “is simply that there is nothing that exists in itself independently from something else. The resonance with quantum physics is immediate.”
(Well, we should note that the resonance is particularly with his theory of quantum physics, but perhaps it’s churlish to point that out.)
The absence of some core, independent entity is known as śūnyatā, which tends to be translated as “emptiness.” So everything, including you and I, are part of this emptiness. He explains:
[L]ooking at a star, do I exist? No, not even I. So who is observing the star? No one, says Nāgārjuna. To see a star is a component of that set of interactions that I conventionally call my “self.”
Networks In and Out
Honestly, I can’t tell if we are literally or metaphorically discussing networks here, but it is interesting to think about the connections between our brains, our physical selves, and our quantum existence.
Our brains are networks, with our sense of self largely being emergent out the electrochemical patterns of neurons. Likewise, the rest of our physical selves are emergent from complex adaptive systems. Now, if Rovelli is on the right track, the whole of the universe is a constantly shifting and flowing network of realities. Reality is only seemingly objective. It is actually contingent and relative.
Everything else is emptiness.
I don’t know if that’s the truth of it, but so sayeth the scholar-saint physicist philosopher Carlos Rovelli. Or, at least, that’s the reality I’ve taken away from our interaction.
How it strikes you is no doubt destined to be different. Still, though our realities must be unique, we are now theoretically entangled: you, me, Rovelli and his thousands of other readers. Luckily, however, emptiness is everywhere, so none of us needs to feel the least crowded. Feel free to stretch out and ponder on your own.