- 2025年8月3日
A Simple Look at Realism, Structuralism in Modern Thought, and the Buddhist Theory of Kū (Emptiness)
A Simple Look at Realism, Structuralism in Modern Thought, and the Buddhist Theory of Kū (Emptiness)
Introduction
My life’s work is to spread contemporary philosophy to the world. From this perspective, there are two special countries in the world: France and Japan.
France is the nation that perfected modern philosophy, to the point where we speak of “French contemporary thought.” What’s remarkable about France is that philosophy is a mandatory subject for the baccalauréat exam, where questions about Derrida and Foucault are commonplace. When I listened to a lecture on Japan by Thomas Piketty, author of Capital in the Twenty-First Century, at the University of Tokyo, his analysis seemed informed by structuralism. Upon investigation, I learned that in France, philosophy, including contemporary thinkers like Derrida and Foucault, is a required subject in high school. This is a unique characteristic of France, as it is not the case in other countries. It seems only France teaches contemporary philosophy to high school students. While other European countries, like Germany, might teach their own philosophers such as Heidegger, studying philosophy without reaching structuralism and post-structuralism feels somewhat incomplete. The reason is that philosophy up to the modern era is relatively easy to grasp intuitively and naturally.
A field of study that feels counter-intuitive, much like quantum theory in physics, could be considered “higher education” if we were to divide education into elementary and higher levels. Even if teenagers don’t fully understand it, I believe there is immense value in simply learning at a young age that such high mountains exist—fields of study that cannot be understood through one’s natural, intuitive methods but must be learned non-empirically and non-intuitively.
Currently, various aspects of Japanese culture are popular overseas, largely through anime, and it is often in France that these booms first ignite. Japan’s reception of continental culture has, from the dawn of its history, been through Buddhism; the history of Japan is the history of Mahāyāna Buddhism. On the other hand, the destination of Western philosophy is contemporary thought, which is essentially the same as Mahāyāna Buddhism. Though they differ in their starting points, their destination is the same, and once reached, they can share the same values. For this reason, when I explain concepts like structuralism, post-structuralism, the Madhyamaka school’s theory of Kū, or the Tendai school’s Theory of the Three Truths, I intend to publish my articles in French as well.
Summary of the Introduction
The key to understanding contemporary philosophy is to understand structuralism. Structuralism is identical to the Mahāyāna Buddhist theory of Kū (emptiness), and its core concept is the understanding of “Kū.” I will try to explain what structuralism and Kū are in a simple way.
The history of Western philosophy is a history woven from the central thread of realism and the ideas that oppose it. In its final phase, this history saw the establishment of structuralism as a powerful antithesis to realism. This current then evolved into post-structuralism, a way of thinking that synthesizes these opposing forces at a higher level through a process of Aufhebung (sublation). Realism asserts that “there is a substance,” that “something actually exists.” Structuralism, in turn, needs to provide something equivalent to this “substance” or “something that actually exists,” but in a form different from realism. While this is expressed in various ways in both contemporary thought and Buddhism, I will use the concept of “Kū,” borrowed from Buddhism as it seems the most fitting name, to explain what structuralism attempted to represent.
Structuralism Was Created to Critique Realism, the Core of Western Society
To understand structuralism, it’s helpful to keep in mind what it sought to explain and why it came into being. The mainstream of Western philosophy is realism. This became particularly prominent after the advent of Christianity. From a biblical perspective, it’s problematic if God and His creation, the world, do not actually exist. Modern philosophy couldn’t quite break away from this, and perhaps it was only when a liberated Nietzsche declared “God is dead” that it became possible to philosophize apart from God.
Explaining the world in terms of reality and substance is relatively easy, natural, and intuitive. It’s similar to how in natural science, classical physics is easy to understand while quantum theory is not. To suggest that things we can repeatedly sense, whose reproducibility we can confirm and share with others through language, might not exist could be seen as a perverse and disingenuous viewpoint. Moreover, if making such a claim could lead to being branded a heretic, tortured, executed, and burned at the stake without a trace, there was no merit in doing so. This is likely one of the reasons why the vibrant “hundred schools of thought” in ancient Greece came to an abrupt halt in the Middle Ages.
However, while realism works well for physical, perceptible objects, it struggles with abstract concepts, ideas, imagination, and symbols that we conjure in our minds. We cannot take them out of our heads and materialize them, and it’s often impossible to share them with others through language. The existence of what is in our minds cannot be proven, nor can evidence be provided. It is difficult to establish whether such things have a substance or actually exist. It was Plato who posited that the true form of these mental objects exists in a world of Ideas, a concept that was quite compatible with medieval theology.
Fundamentally, one could consider that things have two sides: a side that actually exists as a substance, and a side that is grasped by the mind, spirit, or heart. However, in Western philosophy, perhaps due to a particular cognitive habit of Westerners, there is a tendency to take things to extremes and have them fight it out. So, one extreme is realism, and the history of thought progresses through the repeated conflicts and debates between this central pole and the alternative ideas that oppose it.
What Can Replace the Substance of Realism?
From the perspective of common sense and social norms, completely denying realism might seem absurd. And yet, the various imaginations and images that arise in our minds can often feel more vivid and real than the tangible objects right in front of us. But are they a “substance”? Opinions diverge, and there is no universal agreement, so various theories are proposed—and this, in broad strokes, is the history of Western philosophy.
The idea that a substance exists is straightforward. But the opposing ideas—that there is no substance, or that what we think of as substance is actually something else—are, to put it nicely, roundabout ways of thinking, and to put it bluntly, perverse. If it’s not a substance, then what are this reality, this certainty, this sense of being, this immanent presence we feel in our imagination, our inspirations, our concepts, our ideas? We frequently feel that these subjective sensations have a stronger sense of reality and presence than, for example, a physical object presented before our eyes that we can see and touch. How to explain and express this is the history of Western philosophy. This is also true for the history of Eastern thought.
The Case of Eastern Thought
Eastern thought took a different historical path from Western philosophy. About 2,600 years ago, the Buddha Shakyamuni proposed a groundbreaking theory that spread throughout the entire Eastern world.
First of all, there is no creator God in Buddhism. At this point, a Westerner might wonder if this can even be called a religion. While gods do appear in Buddhist scriptures, they are supporting characters. Their existence is optional. The key point is that they can exist, but they don’t have to. This means that in Buddhism, gods are a matter of indifference.
For example, when Shakyamuni attained enlightenment, the god Brahma (one of the three main deities of modern Hinduism) appears. He didn’t help Shakyamuni in his enlightenment, but rather appeared when the Buddha, having solved his problem, considered simply passing away. Brahma’s role was to persuade him to live and spread his teachings to the world. God (in this case, Brahma) plays a role in the genesis of Buddhism, but is irrelevant to the content of its teachings. The teachings of Buddhism itself are indifferent to God. But this indifference is not a negation; gods appear frequently and are friendly towards Buddhism. The gods, in turn, are consistently friendly to Shakyamuni. The two are not in opposition or conflict; rather, they have a win-win relationship. In fact, they got along so well that in later ages in Japan, it led to religious syncretism in the form of Esoteric Buddhism (Mikkyō).
The polytheistic nature of Japanese religion is often attributed to things like the syncretic coexistence of ancient animism with modern civilization (as Lévi-Strauss suggested), Shinto’s “eight million gods,” or Prince Shōtoku’s syncretism of Shinto and Buddhism. However, I believe the influence of Esoteric Buddhism is also significant. There is a saying, “Mountains, rivers, plants, and trees all possess Buddha-nature.” In Esoteric Buddhism, there is a mandalic worldview where the world is a manifestation of the Buddha and Buddha-nature, which takes the form of the various things in the world. To think that Buddha-nature resides in everything is perhaps a sensibility close to animism or Shinto polytheism.
While Western thought can be seen as a struggle between realism and its counter-forces, in the East, a way to name and express that which is non-realist yet appears like a substance was successfully established over 2,000 years ago. This became the orthodox and mainstream thought from Central to East Asia. Shakyamuni called it dependent origination (engi), impermanence (mujō), no-self (muga), etc. Later, Nagarjuna, the founder of Mahāyāna Buddhism, synthesized this under the concept of Kū (śūnyatā).
It is significant that Buddhism flourished for long periods in India, along the Silk Road, and in China. India and China have been superpowers since ancient times. China, in particular, was such a colossal civilizational power for so long that if you were to place the center of gravity of human civilization on a map, it would be near China. India was also a big power, especially before Islam, with influence in South Asia, Southeast Asia, Central Asia, the Middle East, and even Africa. This is evident from the fact that Southeast Asia is part of the Indosphere. Buddhism also spread north to Tibet, Nepal, Bhutan, Central Asia, Mongolia, and among nomadic peoples. Its spread to nomads means it reached the northern part of the Eurasian continent, suggesting it expanded across almost the entire eastern half of Eurasia, including the islands. For a long period in history, for a vast majority of humanity in a wide region, “Buddhism” was synonymous with “civilization.” It’s somewhat mysterious that Buddhism could spread so widely, even with the power of India, China, and nomadic peoples. It seems the countries where it spread were not completely “buddhicized,” and perhaps its advantage was its ability to coexist with other cultures and religions, unlike the exclusivity of Islam or Christianity. At least in Japan, a Mahāyāna country, various non-Buddhist religions remain.
Japan is often called a unique civilization, but this may be due to the uniqueness of Buddhism. Likewise, the supposedly unique character of the Japanese people may also be related to Buddhism. Ambiguity, not stating things clearly, and not being dogmatic are sometimes seen as flaws by other civilizations, but I believe they can also be strengths.
Thus, the influence of Buddhism on Eastern thought is immense, but what is particularly interesting is that Mahāyāna Buddhism is essentially the same as contemporary Western philosophy. Contemporary philosophy, like all of Western philosophy, is a philosophy of how to represent what cannot be represented by realism. With its 2,600-year head start, Buddhism has a more refined terminology and system. It calls it Kū, and the theory explaining it, the theory of Kū.
Here is the beginning of the Heart Sūtra, said to summarize the essence of Buddhism:
The Bodhisattva Avalokiteshvara, while moving in the deep course of Prajñāpāramitā, shed light on the five skandhas and saw that they were all empty (kū). Here, O Śāriputra, form is emptiness (kū) and the very emptiness is form; emptiness does not differ from form, form does not differ from emptiness; whatever is form, that is emptiness, whatever is emptiness, that is form. The same is true of feelings, perceptions, impulses, and consciousness. Here, O Śāriputra, all dharmas are marked with emptiness; they do not appear or disappear, are not tainted or pure, and do not increase or decrease.
The word “kū” (emptiness) appears many times. The famous phrase “form is emptiness, emptiness is form” (色即是空 空即是色, shiki soku ze kū, kū soku ze shiki) is also there. Here, “form” (色, shiki) corresponds to the “substance” of realism. The phrase means something like “substance is emptiness, and emptiness is substance.” It’s best to interpret this not as an opposition between substance and emptiness, but rather as “things have both an aspect of substance and an aspect of emptiness,” or “substance has a part of emptiness, and emptiness has a part of substance.”
This passage from the Heart Sūtra expresses not only emptiness but also the thought of Madhyamaka (the Middle Way), also established by Nagarjuna. The parts “saw that the five skandhas were all empty” and “form is not different from emptiness, emptiness is not different from form” and “all dharmas are marked with emptiness” represent Kū and its theory.
(Note: “Śāriputra” was the disciple who best understood Shakyamuni’s teachings and was meant to be his successor, but he died early, saddening the Buddha. Nagarjuna lived in the 2nd century CE, about 700-800 years after Shakyamuni. He may not have been the first to think of Kū, but it takes time for ideas and terms to mature and become refined. Furthermore, the concept of Kū was translated into Chinese, and in the 7th century, Tiantai Zhiyi synthesized the relationship between Madhyamaka (the Middle), Kū (emptiness), and substance (form/provisional/play) into the Theory of the Three Truths. If Shakyamuni lived around 500-600 BCE, this means that even then, the concept of Kū in Buddhism had been refined for over a thousand years.)
The Counterpart to Substance is Kū
In short, the most fitting counterpart to the “substance” of realism, from a non-realist perspective, is “Kū.” A better expression might be invented in the future, but this one has been in use for nearly 2,000 years and thus carries significant weight.
In the Buddhism taught by Shakyamuni, that which corresponds to the “substance” of realism is referred to by various aspects of its nature: “causes and conditions” (nidāna), “dependent origination” (engi), “no-self” (muga), “impermanence” (mujō), “no-dharma” (muhō), etc. It seems Shakyamuni himself struggled to express it perfectly. These are all facets of what he truly wanted to convey, seen from different angles. Lacking a word or concept to express the thing itself, he named it by its aspects and characteristics.
Centuries after Shakyamuni, in the 2nd century CE, a man named Nagarjuna appeared and revolutionized the state of Buddhism, which had been divided into various schools debating the interpretation of the master’s teachings. He expressed the core of Shakyamuni’s teachings with the concepts of “Kū” and “Madhyamaka” (the Middle Way) and founded the Madhyamaka school. This is the origin of Mahāyāna Buddhism.
The “Kū” that Nagarjuna spoke of is the alternative to the “substance” of realism in non-realist thought. This was not a naming by aspects or characteristics, as Shakyamuni had done, but a direct naming of the core concept.
Visually, “Kū” resembles nothingness or void. Read in Japanese as “kara,” it can be interpreted as such. However, the difference is that while “Kū” can be nothingness or void, it is, more importantly, capable of being “existence” (有, yū). And the true value of the word “Kū” becomes clear when it is existence. As “existence,” it has various aspects and characteristics. Or rather, “Kū” is something that is made, or can be made, from various aspects and characteristics. “Substance” is always primarily “existence” and secondarily has various aspects. “Kū” is the opposite: it is something that is secondarily made, can be made, from various aspects and characteristics.
Conversely, in Buddhism, the substance of Western realism is called “play” (戯, ge) or “provisional” (仮, ke). One could have perhaps said “form” or “real,” but it’s likely these terms were used to emphasize its meaning as a counterpart to Kū.
Here, I’ll introduce the examples of Lévi-Strauss’s explanation of the East-West difference regarding the “ego” and Thomas Piketty’s on “equality.” Lévi-Strauss explains the Cartesian ego (“I think, therefore I am”) as follows: In the West, the existence of the “I” is primary. From the existence of this “I,” various things concerning the “I” are thought of centrifugally and secondarily. Japan is the reverse. On the outside, there is an external shell of surrounding circumstances, various conditions, and objects that exist primarily. The “I” is created centripetally, as a node in the network, the mesh, the matrix of relationships and structures of these external conditions. The “I” is secondary. And without the network of relationships and structures with the outside, the ego (“I”) does not exist. In this sense, the “I” is “kū”; it “is,” but in a way different from a substance. This is “no-self” (muga). It means the “I” is not a “substance” but a “kū.”
Next, let’s take Piketty’s example of “equality.” In the West, “equality” is something given primarily, without question, as a precondition of systems, ethics, and law. One could even say it is imposed. This presupposed “equality” is built into systems, ethics, and laws, and as a result, it shapes people’s ideas about equality and the form of society. In Japan, it’s the reverse. Equality is psychologically embedded in people’s hearts from the start as a part of culture, ethics, and spirituality. The character “bun” (文) in “bunka” (文化, culture) in Japan means matrix or text, a web or network. As a result, people try to be equal to one another, and this becomes a generative force that leads to the construction of equal systems and laws, and consequently, the formation of an equal society. This was Piketty’s way of explaining why Japan is so clearly different and more equal than other advanced nations within the context of neoliberalism, globalism, and a society driven by economic desire and financial capitalism. In this case, in the West, “equality” is a real, existing substance. In Japan, it is a “kū” born from a structure of culture, ethics, spirituality, and truth.
The Equivalent of “Kū” in Western Philosophy
Returning to Western philosophy, it has developed centered on realism, but there are things that cannot be explained well by substance alone. Therefore, as a counter to realism, various different theories have been developed—this is one aspect of the history of Western philosophy. If realism asserts that any given thing is real, then to counter it, one must assert that things are something other than real. The history of Western philosophy can be said to be the search for this “something else,” for its components, and for its expression.
Historically, in the medieval debate on universals, nominalism argued against realism that this “something else” was a “name.” In antiquity, before Socrates, a hundred schools of thought bloomed; Socrates himself may have been great for proposing meta-cognition and relativity, but he was fundamentally a realist. If Plato’s theory of Forms is realist, then Aristotle’s theory of hylomorphism might be seen as slightly non-realist (because substance changes), but Aristotle himself is a realist. In antiquity, the Sophists, who used rhetoric rather than logic, may have been more non-realist.
British empiricism explained this “something else” as a “tabula rasa,” where “experience” is written in place of substance. Continental rationalism and British empiricism called substance the “thing-in-itself,” and its opposite, the “ideational product” imagined by human sensibility, understanding, and reason. German idealism posited that there is no sensory, material substance as realism claims, but that only ideas truly exist. Phenomenology, uncertain about the existence of substance, bracketed it and argued that only “phenomena” and “presence” can be scientifically studied by humans. Heidegger considered how phenomena and presence arise and thought of them as “meaning” and “equipment.” Nietzsche believed that substance does “not exist” (nihil), and that what is considered substance is an apparent object created by the psychodynamics of the human spirit, driven by certain desires, ressentiment, or the will to power.
In structuralist philosophy, one might call the opposite of substance “structure.” However, each thinker has devised their own terminology. Lévi-Strauss uses the term “bricolage.” This implies that the essence is not substance but “kū.” In his work “The Empire of Signs,” Lévi-Strauss states that at the center of Japan (referring, I believe, to the Imperial Household or Palace) there is a giant “void,” a “vacuum,” a “blank space.” Lacan, in structuralist psychoanalysis, calls it “the big Other” (A), or expresses it as the “overlapping of the Imaginary, the Symbolic, and the Real.” Baudrillard uses the terms “simulacrum” and “simulation” for the counterpart to substance. Interestingly, in a reversal of Eastern philosophy, he calls the “kū” that was supposed to be the counterpart to “substance” a “play” or “provisional.” The influence of realism must have been that powerful.
Post-structuralist thinkers have expressed what corresponds to “kū” in a great variety of words. Derrida named it “différance” and criticized substance as the “metaphysics of presence.” If we see “substance” as metaphysical and “kū” as physical, this again looks like an inversion of the relationship between “kū” and “provisional/play” in Eastern thought. Again, the idea of substance (entity) in realism must have been incredibly powerful. It seems that Kū is treated as a newcomer, like virtual reality or a virtual entity. This is an inversion of the relationship seen in Buddhism and Eastern thought, which have valued “kū” for 2600 years. Deleuze and Guattari have used diverse expressions for “kū,” such as “rhizome,” “nomad,” “machine,” “particle,” or “schizo” versus “parano.”
To summarize, in Western philosophy, there are many names for what corresponds to the non-realist counterpart of realism’s substance (which is called “kū” in Eastern thought): “name,” “experience,” “tabula rasa,” “idea,” “phenomenon,” “presence,” “nothing” (nihil), “meaning,” “equipment,” “bricolage,” “the big Other,” “the overlap of the RSI,” “simulacrum,” “différance,” “rhizome,” “nomad,” “body without organs,” “particle,” and so on. These may be aspects, characteristics, profiles, IDs, or functions, but they do not feel necessary and sufficient. They only capture one side, may contain extraneous meanings, or may be interpreted with crucial meanings missing. There is no sense of the minimal, of “knowing what is enough,” of stripping away the unnecessary. They lack an orientation towards the essence of the concept and its name, and they lack refinement, history, and tradition.
For these reasons, “Kū” is probably the most suitable word. This is not a problem specific to Western philosophy; even in Eastern thought, it took 700-800 years after the Buddha first identified this concept for it to receive the name “Kū.” Moreover, the word “Kū” has been in use for nearly 2,000 years, during which it has traveled from India to China via the Silk Road, been translated and contemplated, and has been in use for almost two millennia. It might be better to think that society has been formed in accordance with the word “Kū” over these 2,000 years. This is especially true in a country like Japan, where its very history (the recorded activities of its people) coincides with Buddhism, that is, with “Kū.” From the temples of Nara and Kyoto to contemporary manga and anime, and even the ambiguous, non-assertive character of the Japanese people, all are influenced by Kū and Madhyamaka.
In Summary: Non-Realism is the Theory of Kū
The problem with structuralism is that while it made a great innovation by discovering what corresponds to emptiness in realism, it failed to express it or name it well. Since it’s called structuralism, one might think “structure” is what it aims to explain, but that approach can sometimes be confusing. Structuralism is meant to explain what stands in opposition to the “substance” and “actual existence” of realism. To oppose substance, contemporary thought in structuralism and post-structuralism came up with various names: “différance,” “bricolage,” “presence,” “simulacrum,” “rhizome,” “body without organs,” “particle,” “nomad,” “the big Other,” and so on. But all of them seem difficult to grasp intuitively, are imbued with nuances from a specific perspective, or are lacking something, failing to express it properly.
On the other hand, the theory of Kū in Buddhism, which is the same ideology as structuralism, represents it with the word “Kū.” “Kū” is quite an apt expression. It’s not a word borrowed from another field but a word crafted to express something essential, so it lacks extraneous nuances or missing parts. Originally, Buddhism used words like “dependent origination,” “no-self,” “impermanence,” and “no-dharma” to express the same thing. Hundreds of years after the Buddha, Nagarjuna, the founder of Mahāyāna Buddhism, synthesized the Buddha’s teachings in a theory called the theory of Kū, summarizing it with the word and concept of Kū. Thereafter, the Buddhism that spread throughout Central and East Asia was Mahāyāna, and Nagarjuna’s theories of Kū and Madhyamaka continued to be at the core of Buddhist doctrine.
The great restorer of Chinese Buddhism was Zhiyi of the Tiantai school, who summarized the core teachings of Mahāyāna into three theories—the “Middle” (中), “Emptiness” (空), and “Play/Provisional” (戯/仮)—and the synthesis of their relationships is called the Theory of the Three Truths. This worldview where the three interpenetrate, the Santai En’yū, is the doctrine of the school of the Great Buddha of Tōdai-ji in Nara. This is the same as the core content of post-structuralism, but far more organized.
(Note: Saichō, who trained in the Tiantai school and founded the Tendai school in Japan, seems to have had a troubled life, so he may not have fully understood the Theory of the Three Truths. Likewise, Kūkai of the Shingon school was too focused on Esoteric Buddhism, so I’m a bit skeptical. It is said that Nichiren claimed, “Only the Theory of the Three Truths and the Lotus Sutra are important,” so it’s possible he understood the core of Buddhism, but this is debated. However, for a religion, even for the Buddha, the core theory is not enough; managing a community and teaching morality are necessary for propagation, so the actual situation is hard to know.)
Conclusion
What is important, I believe, is to spread contemporary philosophy to the world. I am not Thomas Piketty or Lévi-Strauss, who could only be pessimistic about the future of humanity, but contemporary philosophy and the Mahāyāna theories of Kū, Madhyamaka, and the Three Truths have the potential to be a hope for humanity. There is a line in the Bible that says one day the law will be carved not in letters, but in your hearts.
If we cannot control the exclusivist ideology of realism and the logocentrism that underlies the affirmation of desire in economism, progressivism, and rationalism, then the future of humanity, the Earth, the world, and the environment will not be bright, just as Lévi-Strauss and Piketty said. Resources are not infinite, and we have destroyed or lost far too much of our natural environment in ways that are irreversible, and our awareness of this is vague, while the process radically accelerates in reality.
In this humble text, I have explained realism and structuralism (= the theory of Kū). Realism is the idea that there is substance, that things actually exist. This is easy to understand, so it is the central theory of philosophy. On the other hand, non-realism, which culminated in structuralism in Western philosophy, is a bit harder to grasp. In Eastern thought, it has long been given concepts and names like dependent origination, no-self, impermanence, no-dharma, and Kū, but since this is also a bit difficult, I have tried to explain it simply.
What the Buddha realized is expressed in terms like dependent origination, impermanence, no-self, etc., but in later Mahāyāna Buddhism, it was summarized with the word and concept of “Kū.” The key point is that Kū is not nothingness or void. In Kū, there is clearly something. And people feel it. Sometimes they even feel a sense of reality, and other times they feel it vaguely, with a sense of profound mystery. Sometimes people don’t feel it, but that doesn’t mean it isn’t there; the point of “Kū” is that there is something that is not felt. The key point of nothingness or void is that they are not there, so they are different from Kū.
So what is the difference from substance? Substance is easy to show, to be shown, and to feel like you understand. The key point of substance is that it can be understood through the senses and can be repeatedly demonstrated. Even with conceptual matters, you can convey them with words and feel like you understand each other. Modernism, classical modern philosophy, and classical physics are all based on this premise.
What about structuralism or Kū? Like substance, there are parts that feel like they cannot be understood by the senses, cannot be repeatedly demonstrated, or cannot be understood through words, but the characteristic of Kū is that there are also parts that are not like that. In fact, even substance has parts that cannot be understood by the senses, cannot be repeatedly demonstrated, or that don’t make you feel like you understand each other through words. It’s even possible to do this deliberately, and this is what contemporary philosophy often calls “deconstruction.”
Kū can look like a substance or pretend to be one. It’s also possible to make it feel easily understood through the senses, repetition, or words, just like a substance, but it can also be presented with an almost infinite multifacetedness and complexity, or one can stop somewhere in the middle.
Kū, unlike nothingness or void, is not an absence; it is an existence, or something in consciousness, so humans try to express it, to name it. In the case of Buddhism, it took several hundred years from when the Buddha spoke of dependent origination, no-self, etc., to arrive at “Kū.” On the other hand, Western philosophy, although it reached completion as an academic discipline with post-structuralism, its methods of expression and naming are still rough and unrefined.
I believe that Western philosophy could simply adopt the term “Kū (kuu),” which has a track record of being used in a vast region of humanity for about 2,000 years.
Kū may be a way of thinking that existed in ancient times not recorded in history, or that still exists in closed-off regions isolated from the world’s great civilizations. But from now on, perhaps a world of the theory of Kū, a world of the harmonious interpenetration of the Three Truths as described in the Avataṃsaka Sūtra, can be realized. This is because society, born from modern mathematics’ other child, information science and engineering, is becoming inherently contemporary-philosophical, and therefore Mahāyāna-Buddhistic, through the internet and AI.
Eastern philosophy, and Japan from the beginning of its history, had “Kū.” Western philosophy, at its destination, found “Kū.” In the end, they merge onto the same path. I do not think it is a coincidence that France, which institutionalizes contemporary philosophy, and Japan, which has historically integrated Kū and Madhyamaka, are experiencing a cultural resonance and vibration.