Dialogue on Emptiness
Eurus: In our group discussion, you demonstrated that the concept of a bee is not fundamental; individual bees may be similar, but there is no inherent bee-essence. One may say, “bee-essence is the ability to reproduce bees.” However, you showed how gradual evolutionary change refutes this argument. “Consider an ancient bee that, if alive, could reproduce with a modern bee. Now consider an even more ancient bee that can reproduce with the ancient bee but not with the modern bee. Does the ancient bee have two essences, one to reproduce with the modern bee and another to reproduce with the more ancient bee?”
Your conceptual deconstructions remind me of śūnyatā, or emptiness, a tenet of the Madhyamaka Buddhist tradition. Śūnyatā says that nothing has svabhāva—essence, inherent existence, or true identity.
Dijon: Thanks for sharing. I’d like to learn more about śūnyatā because it seems to me that there must be some fundamental things, perhaps particles, that inherently exist. If this weren’t the case, then how could anything exist? Said another way, although I think our minds project the concept of a bee onto an external reality, I still think there are aggregates of fundamentally existing things which we call bees.
Eurus: Before I continue, I should point out that I’m not especially well-acquainted with Madhyamaka thought, so my comments may not be precisely correct.
Dijon: I appreciate that you are willing to engage with me on these essential questions, even if you aren’t entirely sure of your own beliefs. Please continue!
Eurus: Śūnyatā doesn’t say that nothing exists, but only that nothing has svabhāva—essence, inherent existence, or true identity. Śūnyatā is closely related to dependent origination, or pratītyasamutpāda. According to this doctrine, all phenomena arise in dependence upon other phenomena, which themselves arise in dependence upon other phenomena. Dependent origination leads to śūnyatā because phenomena can’t exist independently. Things do exist conventionally, similar to how Theseus’s ship exists conventionally. The error is to think that anything exists in-and-of-itself.
Nāgārjuna, who founded the Madhyamaka Buddhist school, summarizes this in a famous verse of his Mūlamadhyamakakārikā:
Whatever is dependently co-arisen
That is explained to be emptiness.
That, being a dependent designation
Is itself the middle way.
Something that is not dependently arisen,
Such a thing does not exist.
Therefore a thing with svabhāva
Does not exist.
You say that particles exist in-and-of-themselves. While we can come up with a scientific theory with constructs like particles or wave functions at the bottom, I do not believe that science itself supposes these constructs have svabhāva. This would be true even if we found the correct theory of everything. For example, it seems tenuous to claim that wave functions fundamentally exist. To the physicist, a wave function is a mathematical tool that describes our observations. To say more is to go beyond what empirical science can support.
Dijon: I think I’m using the term fundamentally exist differently than you’re using svabhāva. When I say something fundamentally exists, I mean it influences reality, and it can’t be broken into smaller pieces. Accordingly, if a wave function completely describes the behaviors we observe and can’t be replaced by a simpler construct, then I would say it fundamentally exists.
Eurus: What does it mean to say something “influences reality” or that something “can’t be broken into smaller pieces”? Our discussion reminds me of a passage in The Feynman Lectures about the philosophical implications of quantum mechanics that may be helpful. I’ll read it:
Another thing that people have emphasized since quantum mechanics was developed is the idea that we should not speak about those things which we cannot measure. Unless a thing can be defined by measurement, it has no place in a theory. And since an accurate value of the momentum of a localized particle cannot be defined by measurement it therefore has no place in the theory.
The idea that this is what was the matter with classical theory is a false position. It is a careless analysis of the situation. Just because we cannot measure position and momentum precisely does not a priori mean that we cannot talk about them. It only means that we need not talk about them. The situation in the sciences is this: A concept or an idea which cannot be measured or cannot be referred directly to experiment may or may not be useful. It need not exist in a theory. In other words, suppose we compare the classical theory of the world with the quantum theory of the world, and suppose that it is true experimentally that we can measure position and momentum only imprecisely. The question is whether the ideas of the exact position of a particle and the exact momentum of a particle are valid or not. The classical theory admits the ideas; the quantum theory does not. This does not in itself mean that classical physics is wrong.
When the new quantum mechanics was discovered, the classical people—which included everybody except Heisenberg, Schrödinger, and Born—said: “Look, your theory is not any good because you cannot answer certain questions like: what is the exact position of a particle?, which hole does it go through?, and some others.” Heisenberg’s answer was: “I do not need to answer such questions because you cannot ask such a question experimentally.” It is that we do not have to. Consider two theories (a) and (b); (a) contains an idea that cannot be checked directly but which is used in the analysis, and the other, (b), does not contain the idea. If they disagree in their predictions, one could not claim that (b) is false because it cannot explain this idea that is in (a), because that idea is one of the things that cannot be checked directly.
It is always good to know which ideas cannot be checked directly, but it is not necessary to remove them all. It is not true that we can pursue science completely by using only those concepts which are directly subject to experiment.
Dijon: The ideas in this passage can indeed improve my definition: Let’s say something fundamentally exists if it is an irreducible construct in a theory that explains all our empirical observations.
Eurus: Your second definition is better, but what does it mean to be “irreducible”? Quantum mechanics can be formulated in several different ways. Are constructs that are only present in some formulation irreducible? Could such a construct, especially if it can’t be directly measured, be said to exist in any normal sense of the word? They seem more like mathematical machinery to me.
Dijon: Such constructs do feel like mathematical machinery. But how could it be otherwise? If the universe consists of small and simple particles and eyes are large and complex aggregates of particles, then eyes would necessarily not be able to see particles. If we also assume that the universe is ordered, then particles would follow mathematical laws and would be indirectly-known mathematical machinery.
Eurus: Are you sure an eye necessarily couldn’t see a single particle? In our universe, human eyes can detect individual photons.
Dijon: It can, in special circumstances. However, given that the eye and the brain require an immense number of particles to detect a single photon, they couldn’t operate at the scale of the particles. It would be too much information.
Eurus: Couldn’t an eye see a focus down on a small number of particles? I’m not sure I see your point.
Dijon: It’s not clear to me either, so I’ll give another example: Imagine a universe consisting of mind as well as particles. Sight is a fundamental property of mind, thus mind can see particles directly. It would be as if our vision was pixelated, and the laws of physics appeared to operate on pixels. Even in this universe, how would minds know they were seeing the things-in-themselves? How could they know they hit bottom?
Perhaps the mathematical machinery is the thing-in-itself. The existence of multiple formulations doesn’t seem to disprove this; information can always be represented in several ways—certainly, a grid of pixels can be.
The physicist studying the laws of nature is in the same situation as the programmer reverse-engineering a software libraries’ interface without access to the implementation. If the implementation acts in a consistent way, then with enough effort, we may be able to perfectly understand and describe the interface. We could predict how it would work in future situations. However, we would have no way of knowing anything about the software library besides its observable behavior. We could hypothesize about how it is implemented—what the particles are in-and-of-themselves—but we would have no way of validating the hypotheses.
Therefore, I agree empirical science can’t say anything about the thing-in-itself. However, if to have svabhāva means something different than to fundamentally exist, then by definition, it is a property of the thing-in-itself that is beyond the reach of science.
This doesn’t mean there aren’t things-in-themselves below the mathematical machinery or that svabhāva is a meaningless term. If we spoke about the sensation of blue to a citizen of a blueless universe, they wouldn’t know what we mean—but that doesn’t mean blue isn’t a valid concept. But it does mean we would require divine revelation to know whether anything has svabhāva. In our software analogy, divine revelation is like the library’s author telling us unobservable implementation details.
Eurus: You make some interesting points. You’ve defined fundamentally exist to ensure that empirical science can verify it. I agree, according to this definition, that wave functions fundamentally exist. I don’t think it follows, however, that wave functions have svabhāva.
How is svabhāva different than your term fundamentally exist? The most important difference is that svabhāva is ultimately an idea about cognition. Ordinary beings misapprehend phenomena as ultimately real entities, existing in themselves, having svabhāva, as a result of their delusion—or avidyā. Awakened beings, having exhausted their delusion, perceive phenomena as they truly are: illusory, dreamlike, and conceptually fabricated. Liberation is only achieved by uprooting avidyā, not just by knowing about avidyā. In a sense, it’s like directly perceiving the thing-in-itself and realizing there’s nothing there. An analogy commonly used to demonstrate this is that Buddhist teachings are like a map of a territory. It is necessary to study the map, but that alone doesn’t get you to the destination. Still, it is useful to engage in the intellectual analysis because this can push one to relinquish false views that they may have about reality, paving the way for new understanding to arise.
What can then be said about svabhāva from a more precise, metaphysical perspective? Nāgārjuna says at the beginning of chapter 15 of the Mūlamadhyamakakārikā:
Svabhāva cannot reasonably occur
Due to causes and conditions.
Svabhāva that arises due to causes and conditions
Would be svabhāva that is produced.
“Svabhāva that is produced,”
How could that be right?
Svabhāva is not fabricated
And does not depend on anything else.
One way to understand svabhāva is through the idea of disappearance under analysis. If you analyze the notion of a chair, the chair disappears and you are left with wooden parts. The chair is not an ultimately real entity; it doesn’t possess svabhāva. You, of course, know this, since our conversation began with you making the notion of a species disappear, but this is only one type of existential dependence.
The dGe-Lugs tradition identifies three types of existential dependence: dependence on causes and conditions, dependence on parts, and dependence on the designating mind. These exist within a hierarchy, with the dependence of the designating mind being the most subtle and incorporating all three.
Svabhāva is thus a stronger notion than your term fundamentally exist, which permits dependence on causes and conditions.
For example, a wave function is different at every point in time. Therefore the idea of the wave function as a single entity that changes over time can be decomposed into a sequence of wave function snapshots in succession, similar to how we decompose a chair into its parts.
Dijon: If a wave function snapshot fully determines the next snapshot, then it seems the essence of the wave function is present in the first snapshot.
Eurus: This could be true for a simple idealized wave function, but any real wave function will depend on changing boundary conditions. For example, a quantum harmonic oscillator may evolve deterministically, but what maintains the quadratic potential? Unless the entire universe was just a harmonic oscillator, it would change eventually, and when it does, there would be existential dependence; you would no longer be able to predict the wave function’s future state from its current state, and there would be no essence.
The division between a system and its surroundings is a useful approximation, but you can’t splice the world like this. This is true even in classical mechanics, but in quantum mechanics, entanglement even more strongly prohibits the division, since two particles that are far apart can affect one another. David Bohm describes this nicely in one of his papers:
A quantum many-body system cannot properly be analyzed into independently existent parts, with fixed and determinate dynamical relationships between each of the parts. Rather, the “parts” are seen to be in an immediate connection, in which their dynamical relationships depend, in an irreducible way, on the state of the whole system (and indeed on that of broader systems in which they are contained, extending ultimately and in principle to the entire universe). Thus, one is led to a new notion of unbroken wholeness which denies the classical idea of analyzability of the world into separately and independently existent parts.
As you know, Bohm’s interpretation of quantum mechanics is one of a few. However, I think this point is valid in all interpretations.
Dijon: I think you’re correct. Let me read a quote from Sean Carroll:
A feature that is common to all interpretations of quantum mechanics is that what we see when we look at the world is quite different from how we describe the world when we’re not looking at it. In a sense it is the ultimate unification: not only does the deepest layer of reality not consist of things like “oceans” and “mountains”; it doesn’t even consist of things like “electrons” and “photons.” It’s just the quantum wave function. Everything else is a convenient way of talking.
Therefore, I was mistaken when I said “perhaps particles” are the fundamentally existing building blocks of reality. Electrons, like bees, are a conceptual projection onto the universe’s wave function.
In another place, Carroll says the wave function may evolve deterministically. If this is the case, then would you say that the wave function of the universe has svabhāva?
Eurus: If the universe was only a single deterministic wave function, I think it would fundamentally exist and potentially have svabhāva. But I disagree with the premise. It’s unfathomable to me that consciousness and volition could exist in such a universe. Therefore, I think the non-deterministic interpretations of quantum mechanics are correct. After all, they are all interpretations; no objective evidence can be used to distinguish them.
Dijon: Even if we accept a non-deterministic interpretation, the laws of physics themselves are static. Perhaps this provides the wave function essence?
Eurus: I don’t think so. It’s incoherent to speak of the laws of physics in isolation. Imagine there was no physical universe—perhaps all that existed were a set of minds in a formless realm. In what sense could you say that the laws of physics exist? Without physical phenomena that evolve in accordance with the laws of physics, the laws of physics have no meaning. They can’t stand alone; they only exist as properties of physical phenomena, and in that sense they depend on physical phenomena for their existence. Like particles and bees, they disappear under analysis. When you analyze the essence of the laws of physics, you’re left with nothing but physical phenomena evolving as described by those laws.
Dijon: I see, if the laws of physics are a description, then they can’t give the wave function an essence. What if the wave function behaves a certain, fixed way, and the way it behaves is the essence?
Eurus: I’ll have to consider this argument further.
We’ve been discussing śūnyatā from a metaphysical perspective and exploring how it relates to physics. But śūnyatā is ultimately an insight into the nature of the mind—this very reality that we are in direct contact with. As such, it is something that can be directly known, but only via a direct perception of emptiness, and that only occurs when the first bhūmi—the first spiritual attainment of the bodhisattva path—is realized.
In this sense, I don’t believe that śūnyatā can be known without some kind of revelation. Although not a divine revelation, as you said earlier, since that implies it can only be known through the testimony of an omniscient being. That alone isn’t an adequate means of knowledge, because then how do you know that the being is omniscient and truthful? In a way, there is some divine revelation at play here—the Buddha is omniscient—but the important difference, as stated above, is that confirmation is possible via direct perception.
If emptiness seems difficult to pin down, you’re in good company—I don’t think the idea can ever be fully grasped without realization. After all, its realization demarcates bodhisattvas from ordinary beings. Given this, I think that it would be prudent to give the idea space to evolve and to withhold judgment. There is a Zen metaphor about this, which I’ll read:
Nan-in, a Japanese master during the Meiji era, received a university professor who came to inquire about Zen.
Nan-in served tea. He poured his visitor’s cup full, and then kept on pouring.
The professor watched the overflow until he no longer could restrain himself. “It is overfull. No more will go in!”
“Like this cup,” Nan-in said, “you are full of your own opinions and speculations. How can I show you Zen unless you first empty your cup?”
Not that your tea cup is full, but it can be helpful to have this in mind when approaching a new set of ideas. And, of course, it is perfectly valid to go back and compare or critique after having first considered the new ideas on their own terms.
Dijon: My cup is partially filled with a physicalist world view, but I will try to empty it. I’ve often pondered how consciousness could arise from matter. Despite this, I’ve always viewed the mind, our brain, and our senses as a small object in a vast external world. I’ve never seriously considered whether the mind could be primary and the external world secondary.
If the mind were primary, then I could imagine how one could know that nothing has svabhāva, even if this weren’t apparent in the laws of physics.
I have to go, but perhaps when we resume our conversation, we can explore why you think the mind is primary?
Eurus: That sounds good. I look forward to it.