Correspondences between Contemporary Philosophy and Mahayana Buddhism: Realism (Jitsu, Realism) vs. Emptiness (Kuu), and Madhyamaka vs. Post-Structuralism

Introduction Contemporary philosophy and Mahayana Buddhism share essentially the same conceptual framework. In short, their correspondences can be summarized as follows. This article elaborates on these parallels. Contemporary Philosophy and Buddhism are Essentially the Same To state the conclusion upfront, contemporary philosophy (modern thought) and Mahayana Buddhism are essentially identical. To be more precise, structuralism in contemporary philosophy corresponds directly to the Buddhist concept of emptiness (Kuu). Furthermore, a part of post-structuralism in contemporary philosophy aligns with Madhyamaka (Middle Way theory) in Buddhism. Strictly speaking, structuralism and emptiness theory (Kuu-ron) are nearly identical. Meanwhile, Madhyamaka is analogous to post-structuralism once structuralism and various other theories are removed. Recently, a useful term has emerged to simplify this: meta-cognition. In short, Madhyamaka and the essence of post-structuralism minus structuralism and other theories can both be described as meta-cognition. Meta-cognition means "cognition about cognition." What is being cognized? Various ways of thinking, ideologies, theories, information-processing methods, ethics, moral guidelines, religions, and philosophies—in other words, all conceptual frameworks. In computer terms, meta-cognition corresponds to an operating system (OS), while various ways of thinking and ideologies are applications. Historically, the "applications" were discovered before the "OS." In Buddhism, the Buddha first realized the doctrine of emptiness (dependent origination, "all five aggregates are empty"), and subsequently, Madhyamaka emerged inevitably. In contemporary philosophy, structuralism emerged first, naturally leading to post-structuralism. Although applications precede the OS historically, humans naturally use software (applications) rather than consciously recognizing the OS. Realism as the Centerpiece of Philosophy Major global powers, religious states, and nations in the process or aftermath of modernization tend to be perceived as dualistic. However, closer inspection reveals they often operate on a division between monism and "otherness." Modernization tends to create a binary: Western-centrism vs. others. Religions have exclusivist monotheism vs. others. Politics, society, and economy have liberalism vs. others. Philosophy often revolves around realism vs. others. However, the "others" category is frequently misconstrued as opposing realism, causing confusion. "Non-" differs from "anti-" as the latter implies exclusivity. Philosophically, realism has been central since ancient times. During medieval theology, realism opposed nominalism. Rationalism opposed empiricism, German idealism opposed realism, existentialism opposed realism, phenomenology opposed realism, and structuralism opposed realism. Post-structuralism finally clarified and resolved these tensions. Uniqueness of Buddhism: Western vs. Eastern Thought While Western modern civilization unfolds as described above, Eastern thought—particularly Buddhism—is the inverse. Over 2500 years ago, the Buddha anticipated and formulated structuralism and post-structuralism. In Western philosophy, the opposition between realism and non-realism dominated. Buddhism, however, integrates non-realism inclusively, without opposing realism. Japan, a rare Mahayana Buddhist country, appears uniquely alien to Western observers due to this integrated viewpoint. Why Realism Dominates: Substance (Thing) vs. Concept (Event) Realism is intuitive, straightforward, and aligns with basic human cognitive development—sensory experience precedes abstract conceptualization. Humans perceive the world through sensory experiences (substance) and abstract concepts (events). Realism emphasizes the sensory, material aspect, while non-realism emphasizes the conceptual, abstract aspect. Emptiness (Kuu-ron) and Structuralism vs. Realism Structuralism in contemporary philosophy directly corresponds to Buddhist emptiness theory, representing a mature non-realism. Western philosophy historically lacked a direct concept analogous to emptiness, leading to indirect expressions like nominalism, empiricism, and phenomenology. Medieval Realism vs. Nominalism and Emptiness Medieval theology debated realism (existence of universals) vs. nominalism (existence attributed through naming conventions). Lacking the term "emptiness," nominalism expressed emptiness indirectly. Rationalism, Empiricism, and Emptiness Continental rationalism (innate reason) is realist. British empiricism (knowledge through experience) indirectly expresses emptiness through experience as the basis of conceptual construction. Descartes’ Dualism and Emptiness Descartes bases philosophy on the intuitive realism of the ego, supported ultimately by God’s existence. His analytical method can result either in constructing reality (realism) or viewing constructions as empty frameworks (structuralism). German Idealism and Emptiness German idealism resolves Kantian dualities by making all phenomena constructs of consciousness—essentially aligning with structuralism and emptiness theory. Phenomenology (Husserl) and Emptiness Husserl’s phenomenology brackets the question of existence (epoché), focusing on appearances (phenomena), effectively considering them as "constructive components of emptiness." Nietzsche and Emptiness Nietzsche explicitly aligns with emptiness by describing the world as chaos, shaped dynamically by drives and will to power, corresponding closely to the Buddhist doctrine of dependent origination. Structuralism and Post-Structuralism in Various Fields Structuralism dominated 20th-century thought, reinterpreting cultural anthropology (Lévi-Strauss), psychoanalysis (Lacan), Marxism (Althusser), and humanities (Foucault). Mathematics itself underwent structural reformulation (Bourbaki group). Summarizing Emptiness and Structuralism In complex modern systems (e.g., AI robots), the realist approach (substance-based) clashes culturally with emptiness (concept-based), especially evident in different cultural portrayals of AI and self-awareness. Components of Emptiness Non-realist theories differ due to the absence of an emptiness concept. Thus, emptiness theory is articulated indirectly through nominalism (symbols), empiricism (experience), idealism (ideas), phenomenology (appearances), and structuralism (structures). Brief Overview of Post-Structuralism Post-structuralism, meaning "after structuralism," aligns closely with "meta-cognition," or cognition about cognition. It transcends structuralism by reflecting upon various conceptual frameworks. Buddhism calls this meta-cognition "Middle Way" (Madhyamaka). Post-structuralism might better be called "meta-structuralism," focusing explicitly on meta-cognition. Expressing Emptiness and Meta-Cognition While emptiness still lacks a perfect Western analogue, various philosophers have attempted to express it: Derrida’s différance, Deleuze and Guattari’s rhizome, and Lacan’s symbolic-imaginary-real schema. Conclusion Contemporary philosophy aligns closely with Mahayana Buddhism’s Threefold Truth (Middle Way, Emptiness, Provisionality). Specifically: Contemporary philosophy ≈ Mahayana Buddhism Post-structuralism (core) ≈ Madhyamaka (Middle Way) Structuralism ≈ Emptiness theory (Kuu-ron) Recognizing these parallels clarifies both contemporary philosophy and Mahayana Buddhism.

A Comparison of Contemporary Thought and Mahayana Buddhism: Realism vs. Śūnyatā (Emptiness), Madhyamaka vs. Post-structuralism

Introduction Contemporary philosophy and Mahayana Buddhism are, in essence, the same school of thought. To state the conclusion first, they share the corresponding relationships outlined below. This article aims to explain these parallels. Contemporary Philosophy and Buddhism Are Ultimately the Same To begin with the conclusion, contemporary thought (contemporary philosophy) and Mahayana Buddhism are the same. To be more precise, the structuralism of contemporary philosophy is the same as the Buddhist theory of Śūnyatā (空論, kūron, emptiness). Furthermore, a part of contemporary post-structuralism is the same as the Buddhist theory of Madhyamaka (中観論, chūgan-ron). Strictly speaking, while we can equate structuralism with Śūnyatā, it is the portion of post-structuralism that remains after subtracting structuralism and various other elements that aligns with Madhyamaka. Fortunately, we now have the convenient term "metacognition." In a single word, both Madhyamaka and this refined essence of post-structuralism can be described as "metacognition." Metacognition is the act of cognizing cognition itself. So, what does one cognize? In short, it is the various ways of thinking. This includes philosophies, theories, modes of thought, information processing methods, morals (i.e., principles of action), and ideologies. In high school social studies terms, it encompasses ethics, religion, philosophy, and more. One could even argue that subjects like language, math, science, and social studies—and the various theories within them like those in chemistry—are all ways of thinking, methods of information processing, philosophies, and ideologies. Regarding language, while we cannot know the inner world of those without it, a speaker of a language (or a multilingual person using one of their languages) can be seen as thinking based on that language's cognitive structure. Using a computer analogy, metacognition is the Operating System (OS), while other ways of thinking are applications. Historically, applications were discovered before the OS. In Buddhism, the first thing the Buddha, Śākyamuni, realized was Śūnyatā (dependent origination, the five aggregates are all empty). Subsequently, the Middle Way (中道, chūdō) was inevitably derived as a consequence. In contemporary philosophy, structuralism was discovered first. As a result, post-structuralism was also inevitably derived. It may seem natural that the application comes before the OS, as we typically use applications—or software running on the OS—without being conscious of the OS itself. The History of Philosophy Has Revolved Around Realism Major world powers—nations with scriptural religions, those modernizing, and those already modernized (where modernization can be equated with Westernization)—are often thought to perceive things dually. However, a closer look reveals this is not always the case. More often, things are divided into a singular dominant idea versus "the rest." Modernization: Eurocentrism vs. the rest. Religion: Exclusive monotheism vs. the rest. Politics/Society/Economics: Liberalism vs. the rest. Philosophy: Realism vs. the rest. A common source of confusion in these discussions is a cognitive bias that tends to interpret "the rest"—which should be understood as "non-"—as "anti-". The difference is whether they are mutually exclusive. For example, the political divide between liberalism and "the rest" is often misunderstood. "The rest" is sometimes called conservative or right-wing. However, "anti-liberalism" is a stance that opposes and conflicts with liberalism, whereas "non-liberalism" can comfortably include liberalism. This is why conservative discourse in Japan and its ruling party have traditionally encompassed a wide range of ideas, including liberal ones. The definitions of liberal and non-liberal also change with time and across countries, making it confusing for non-specialists. Furthermore, we tend to think of these as opposites on the same axis—like points on a number line—when they may exist on entirely different dimensions, leading to discussions that fail to connect. In philosophy, realism has been a constant presence since antiquity and was a central theme of debate in medieval theology. In developmental psychology, a child's development proceeds from sensory-motor and intuitive aspects—seeing and thinking about the "thing" (物, mono) side of reality—to the later development of abstraction, mental manipulation, and conceptualization, which is the "event" or "matter" (事, koto) side of reality. Because of this, realism tends to be deeply ingrained in the human psyche and is often considered self-evident. Looking at the history from medieval theology to modern philosophy, the pattern is as follows: Theology: Realism vs. Nominalism (as "the rest"). Early Modernity: Continental Rationalism (a type of realism) vs. British Empiricism (as "the rest"). Later Modernity: Realism vs. German Idealism, vs. parts of Nietzschean existentialism, vs. phenomenology, and vs. structuralism. Finally, within the framework of contemporary post-structuralism, this structure of opposition and contrast was successfully organized, bringing a form of resolution to modern Western philosophy. The Uniqueness of Buddhism: Western vs. Eastern Thought If Euro-centric modern civilization developed in this way, Eastern thought is its inverse. Over 2,500 years ago, a genius named Śākyamuni appeared and single-handedly anticipated and established what would become structuralism and post-structuralism in modern Western philosophy, spreading it across Asia. While Western philosophy's history was a conflict between realism and "the rest," in Buddhism, the thought corresponding to "the rest" was not "anti-realism." It became the mainstream while encompassing realism without denying it. Therefore, in Eastern thought, what is considered the conclusion or end-point in Western philosophy is the starting point, leading to a completely different historical trajectory. Japan, as one of the world's few Mahayana Buddhist nations, can be seen as an exceptionally unique civilization from the perspective of Westerners and others. Because Mahayana Buddhism is often subtle and less assertive in its claims, it has historically been suppressed or destroyed for various reasons. This has made Japan stand out, for better or worse, and has often led to discussions of Japanese exceptionalism. Why is Realism Dominant? "Thing" and "Event," "Thing-ness" and "Event-ness" Realism is an easy-to-understand way of thinking. Let's provisionally call any object of our awareness a "thing-event" (monogoto). Any "thing-event" in the world has the properties of a "thing" and an "event." The "thing" aspect (mono) is material and sensory. Let's call this its "thing-ness" (物性, bussei). This sounds a bit like Heidegger. The "event" aspect (koto) is the side that is cognitively processed in the mind or spirit after being sensed. It is abstract: concepts, ideas, representations, thoughts, imagination. It can also be what we might call perceptions or realizations—the feeling of reality, the sense of knowing or understanding—as well as symbolic aspects like names and various functions or properties. Most objects we can cognize likely have both properties. A "thing" is what can be perceived by the senses. It is difficult to argue that an object placed before you, which you can both see and touch, does not exist. To claim that something perceivable by the five senses through repeated confirmation is non-existent would be absurd. However, even things perceived by the five senses have aspects beyond them. They have names, can be used as tools, analyzed chemically, and hold meaning within a society or culture. These are the "event" properties of a "thing-event." When we grasp things in terms of their cognitive or functional meaning or their relationship with other things, these aspects come to the forefront. The Buddha understood a human being as a composite of the Five Aggregates (五蘊, go-un): form, sensation, perception, mental formations, and consciousness. Form (色, shiki): The material, sensory part of a thing-event. Sensation (受, ju): Feelings or sensations. Perception (想, sō): Representations or concepts. Mental Formations (行, gyō): Will, intentions, actions. Consciousness (識, shiki): Recognition or awareness. The "thing-ness" is covered by form and sensation. The "event-ness" is covered by sensation, perception, mental formations, and consciousness. This perspective is similar to that of Kant in his Critique of Pure Reason. What are Śūnyatā and Structuralism? Their Difference from Realism First, contemporary structuralism corresponds to the Buddhist theory of Śūnyatā (空論, kūron). These represent the completed form of non-realism. Realism is the philosophy of "reality" (実, jitsu), while Śūnyatā is the philosophy of "emptiness" (空, kū). The problem here is that Western thought, knowledge, concepts, and language have no direct equivalent for kū. One could even say that the history of Western philosophy has been a continuous effort to discover, invent, and express something equivalent to kū in opposition to realism. The Medieval Problem of Universals and Śūnyatā Let's trace the history of Western thought from the Middle Ages. In medieval theology, the problem of universals pitted realism against nominalism. Realism, as the name suggests, is the idea that universals (essences) exist in reality—that there is a real substance. In contrast, nominalism argued that substance does not truly exist; we merely give names to things that we perceive as having reality, thereby making them seem real. This convoluted explanation was necessary because the word kū did not exist. From the perspective of Śūnyatā or structuralism, names and the words that contain them are just some of the components that construct emptiness. Continental Rationalism, British Empiricism, and Śūnyatā Moving from the Middle Ages through the Renaissance to the early modern period, we see the rise of Continental Rationalism and British Empiricism. Rationalism is a type of realism, positing that reason and rationality are pre-existing, real entities within humans and possibly the world. Empiricism, on the other hand, argues that there is no pre-formed reason or rationality; such things are shaped posthumously through experience. In the language of Śūnyatā or structuralism, "experience" becomes a component for constructing emptiness. It's like a job applicant's resume or portfolio; a hiring manager uses these documents (the applicant's experience) to make a decision without ever meeting the person in "reality." The "reality" of a face-to-face meeting does not exist at this stage. Descartes's Dualism and Śūnyatā Descartes founded his philosophy on the intuitive reality of the self. The logic is that since the self has reality, what has reality must exist. Ultimately, Descartes grounds his philosophy in the "sincerity of God," meaning God's existence guarantees the existence of everything else, whether created objects or the mind. He proposed a method of elemental reductionism: breaking down a whole to understand its parts, then reassembling them to understand the whole. The question is what happens during this reassembly. Does it create a new substance (the realist position), or does it not (the structuralist/Śūnyatā position)? German Idealism and Śūnyatā German Idealism was an attempt to resolve the "half-heartedness" of Kant's compromise between rationalism and empiricism by explaining everything through a monism of ideas. Kant created a very modern epistemology where the "thing-in-itself" is processed by reason, understanding, and sensibility to form our perception. However, this created a dilemma by separating the "thing-ness" of the thing-in-itself from the conceptual "event-ness" of reason. German Idealism aimed to resolve this by proposing an idealist monism, where even the thing-in-itself and its "thing-ness" are created by ideas. From the perspective of Śūnyatā, the components that construct emptiness might be "ideas," Fichte's "obstacle," or Hegel's dialectical structure. Husserl's Phenomenology and Śūnyatā Husserl's phenomenology brackets (epoché) questions of external reality and substance to focus solely on the phenomena that appear with certainty in the mind. The question of whether "a substance exists, therefore it appears in consciousness" or "it exists because it appears in consciousness" is a later step in thinking. The founder, Husserl, argued that we must separate these questions. From this standpoint, realism is the position that because something is present to consciousness (genzen), we feel its reality and thus conclude that a substance exists. In contrast, the Śūnyatā perspective is that this phenomenon, this presence, is merely one of the constituent parts of emptiness. Nietzsche's Philosophy and Śūnyatā While existentialism doesn't always deal with ontology or epistemology, some existentialists like Nietzsche, Heidegger, and Sartre did. Nietzsche, in particular, developed a philosophy that is virtually identical to Śūnyatā. This is not found in his moral ideas like the eternal return or the Übermensch, but in his assertions that the world is chaos, that ressentiment and the will to power dynamically shape our perception and worldview, and that "God is dead." Nietzsche believed that our world is fundamentally incomprehensible—a chaos—but that psychic drives, both positive (like the will to power) and negative (like ressentiment), form a corresponding perception and mode of being. This is identical to modern structuralism and to the Buddhist concepts of dependent origination (pratītyasamutpāda) and Nāgārjuna's Śūnyatā. In this philosophy, realism is demoted from the center to a mere artificial creation. Other Western Thought and Śūnyatā Around the time of Nietzsche, movements like structuralism, formalism, axiomatism, and logicism emerged in mathematics and linguistics, followed by relationist theories like set theory and category theory. These are already expressions of Śūnyatā. In the natural sciences, quantum theory emerged. While not the same as Śūnyatā, it offers a way of seeing things that encompasses and generalizes classical realism, presenting a worldview entirely alien to those familiar only with classical science and philosophy. A Look at Realism and Non-realism from the Perspective of Śūnyatā and Structuralism The 20th century can be described as the century in which the structuralist view permeated and spread among intellectuals and the general public. By the mid-20th century, Lévi-Strauss had pushed structuralism to the center of the intellectual world. Simultaneously, various academic fields that had been built on realism were being reconstructed with structuralism. It's worth noting that structuralism is an "-ism." While some consider an "-ism" an ideology, it can also be just a methodology or a technique. Taking the latter view, structuralism became the new foundation and principle for various fields of study, which had previously operated on an unconscious premise of realism. The "four horsemen" of structuralism—Lévi-Strauss in cultural anthropology, Lacan in psychoanalysis (structuring the psyche), Althusser in Marxism, and Foucault in the social and human sciences—led this charge. Essentially, the foundations of formal disciplines like mathematics and logic, as well as the natural and human sciences built upon them, were all structuralized. A famous example is the Bourbaki group's effort to rewrite all of mathematics using structuralist principles. Summary of Śūnyatā and Structuralism We've discussed Descartes's method of understanding the world by breaking it down and then synthesizing the parts. This worked in the past, but today's objects are made of an immense number and variety of complex parts—cars, airplanes, weapons, computers. Consider an AI-powered robot or android. This is a common theme in science fiction and a relevant issue today with discussions of the AI singularity. The core question is: what happens if an AI develops a self, a consciousness? In Japan, robots and machines have long been anthropomorphized and treated with emotional attachment. In contrast, the world's dominant Abrahamic religions (Christianity, Islam, Judaism) posit a strict hierarchy where God, humans, and other creatures are essentially different. God is the Creator, and everything else is His creation. Among creations, humans are special, made in God's image. This worldview is inherently distinctive, hierarchical, and realist. To claim that God or His creations do not exist as real substances is highly problematic. This is why, in the medieval problem of universals, nominalism was often seen as heretical. While Japan's Astro Boy and Doraemon are treated like humans, Western films often show a great deal of anxiety around this topic. In 2001: A Space Odyssey, the protagonist's terror and confusion when the AI, HAL, develops a self makes the film feel like a panic-horror movie. In the cyberpunk classic Blade Runner, the moment a replicant (an android) develops a self is initially portrayed with fear but ultimately depicted movingly. Perhaps in the West, the self is seen as something like a soul, the very substance of a human being. The theme becomes what happens when an "empty" (kū) thing like a computer or AI acquires "reality" (jitsu). When complexity theory was popular, there was a saying: "Complex things have a mind." In Japan, however, it is considered normal and even part of the culture to feel a spirit or presence in mountains, rivers, plants—even in nothing at all. Emptiness is Made from Parts We have traced the flow of non-realist thought in Western philosophy as it developed in relation to realism. Non-realist ideas took many forms: nominalism in medieval theology, British empiricism in early modern Europe, German idealism in the height of modern philosophy, and phenomenology in the transition to the contemporary era. Why did it take so many different forms and require such varied explanations? Because the word and concept for Śūnyatā (emptiness) were missing. Instead, these philosophies were expressed using the "parts" that make up emptiness. This was later well-summarized by structuralists like Lacan and subsequent post-structuralists. Nominalism proposed "names, symbols" as the parts. British Empiricism proposed "experience". German Idealism proposed "ideas". Phenomenology proposed "phenomena, presence". Non-realism includes realism. Since it is not anti-realism, it does not exclude realism; there is no strange exclusionism. Therefore, realism itself contributes parts for constructing emptiness: "matter" and "things perceivable by the senses." In Lacan's thinking, these parts are synthesized and assembled to create emptiness. You could just as well say they create "reality" or "substance." However, the modern perspective is that it is unnecessary to presuppose a substance. Śūnyatā and realism are not mutually exclusive ideologies. Being able to use both perspectives simultaneously is a key aspect of post-structuralism. A Brief Explanation of Post-structuralism The term "post-structuralism" is a compound of the Latin prefix "post-" and "structuralism." "Post" means "after" or "next." Interestingly, the equivalent word in Classical Greek is "meta." While "meta" is now often used to mean "beyond" or "above," this usage dates from Aristotle and his influence. Its original meaning was the same as "post": "after" or "next." The transition from structuralism to post-structuralism in contemporary thought was very messy, so classifying it by period was perhaps a good idea at the time. However, from our current standpoint, where we can calmly and objectively organize the situation, it would be more appropriate to either give post-structuralism a completely different name or, if we want to keep the word "structuralism," call it meta-structuralism. Here, "meta" would be used in the modern sense, as in Aristotle's Metaphysics or Meta, the parent company of Facebook. Simple Post-structuralism Though the term wasn't mainstream back then, there is now a perfect word to describe post-structuralism: "metacognition." Post-structuralism is a way of thinking that applies metacognition to any and all philosophies, ways of thinking, scientific theories, religions, and ideologies. Therefore, a more fitting name would be "Metacognition-ism." Buddhism has words for this metacognitive stance. The Buddha called it the "Middle Way" (中道, chūdō), Nāgārjuna called it "Middle View" (中観, chūgan), and the Tiantai master Zhiyi called it the "Middle" (中, chū). Western thought lacked such a word, which is likely why it was named post-structuralism. However, the term "post-structuralism" is a mix of too many things, making it unclear what it refers to. It is helpful to think of it with the following formula: "Post-structuralism in a new sense" = "Metacognition of thought" = "Post-structuralism" - "Structuralist philosophies" - "Realist philosophies" - "Other miscellaneous elements" Understood this way, "post-structuralism in a new sense" becomes identical to "Metacognition-ism" and the Buddhist concepts of the Middle Way, Middle View, and the Middle. How Contemporary Philosophy Expresses Kū and Chū Without the Words Lacking original words and corresponding concepts makes it difficult to express and name new ideas. For the core of post-structuralism (Chū), we can now use "metacognition." In the past, terms like "relativism" were used. In Buddhism, it is simply the Middle Way, Middle View, or the Middle. (Note that this is different from the Confucian "Doctrine of the Mean," chūyō). For emptiness (Kū), there is still no perfectly fitting concept. Perhaps it would be best to just use the word "kū" directly, much like how the Daoist "Tao" (道) is used. Nevertheless, attempts have been made to express it: As we've seen: nominalism ("name, sign, symbol"), empiricism ("tabula rasa"), idealism ("idea, spirit"), phenomenology ("phenomenon, presence"). In the age of structuralism: "structure," Lévi-Strauss's "bricolage," Lacan's diagrams like the Borromean knot (the interplay of the Symbolic, Imaginary, and Real). Foucault used phrases like "the end of man" or "the end of history." In modern mathematics, perhaps "undefined term" or "undefined concept." Derrida, one of the three giants of post-structuralism along with Foucault and Deleuze/Guattari, used the word "différance," which may be close. The word "deconstruction" might also work. Deleuze and Guattari seem to be trying to express something corresponding to kū through various terms like "(body without) organs," "rhizome," "nomad," and "particle." Perhaps all of these capture a certain aspect of emptiness, but none feel entirely complete. It's important to note that kū is different from "nothingness" (無, mu), "void" (虚, kyo), and Taoist concepts like "non-action" (無為, mui). Meanwhile, Mahayana Buddhist countries like Japan have used the concept of kū in interesting ways. For example, Japanese scholars of Dutch learning coined the word "air" (空気, kūki, literally "empty-spirit"). This word has taken on a fascinating social usage, as famously analyzed by the biblical scholar Shichihei Yamamoto in his book "The Study of 'Air'". We have phrases like "can't read the air" (kūki yomenai), "creating an atmosphere," and "pouring cold water on the atmosphere." There is a profound statement in the Bible: "Man cannot live without spirit (pneuma, breath, psyche) and water." Conclusion Contemporary philosophy is the same as the Three Truths doctrine (三諦論, santai-ron) of Mahayana Buddhism. Contemporary philosophy consists of structuralism and post-structuralism. The term "post-structuralism" covers a messy field, including non-realist structuralism, realist philosophies, and other elements. The Three Truths doctrine, summarized by the Tiantai master Zhiyi, consists of the Middle (chū), Emptiness (kū), and the Provisional/Temporary (ke or 仮). Ignoring the finer details, we can draw a direct correspondence: Contemporary Philosophy = Mahayana Buddhism The Core of Post-structuralism = The Middle (chū, chūgan, chūdō) Structuralism = The Theory of Emptiness (kūron) The third truth, the Provisional, corresponds to the various realist and non-realist philosophies themselves, which are the objects of metacognition. I have summarized my thoughts in this humble article in the hope that understanding this correspondence and framework will make both Mahayana Buddhism and contemporary philosophy easier to grasp.

A Simple Explanation of Quantum Theory: Another Mode of Philosophical Existence Quantum Theory as Another Model of Realism

Broadly speaking, contemporary philosophy is divided into structuralism and post-structuralism. Structuralism corresponds to what is called Kū (emptiness) in Buddhism, while post-structuralism corresponds to Chū (the middle), Chūgan (the Middle View), or Chūdō (the Middle Way). Strictly speaking, what remains when you subtract structuralism from post-structuralism is the Buddhist concept of the Middle Way. In a single phrase, it means to view all ways of thinking through meta-cognition—to see them in relative terms. Examples of different ways of thinking include the classical physics or classical mathematical realist view of things, and the Buddhist Middle Way or structuralist view of things. Besides the classical mathematical and physical perspectives, there is another realist way of viewing things: the quantum theoretical perspective. Philosophy, in its narrow sense, consists of ontology (the theory of being) and epistemology (the theory of knowledge). The mode of realism we learn intuitively and before higher education is a Cartesian, or in other words, modernist epistemology and ontology, which is classical in its physics and mathematics. Quantum theory refines classical physics and offers a comprehensive perspective that includes classical physics. You can view it as either realism or structuralism, but since physics itself is fundamentally realist, it might be more conventional to see it as a form of realism. The same can be said for classical physics; while it can be interpreted structurally, the common understanding is that it presupposes the reality of nature, making a realist interpretation more conventional. Here, the purpose is not to explain philosophy but quantum theory. For those who can only see the world through a classical lens, learning about quantum theory can be beneficial. Therefore, I will provide a simple explanation of quantum theory using only words, without mathematical formulas. Before Studying Quantum Theory I apologize to those who are eager to dive straight into quantum mechanics or quantum field theory, but first, I will briefly explain the general state of current physics. Again, I will use words instead of mathematical formulas. Whether you call it a metaphor, inference, analogy, or expedient means, it is crucial to grasp the meaning of a theory, even if it's described by equations—perhaps a broad understanding is even better. It is important to comprehend it not just intellectually, but to have it resonate with you, to feel it "click," whether through natural language, imagery, or narrative, for both yourself and others. This is the stance I will take, in line with the title, "A Simple Explanation of Quantum Theory." However, while I won't present the formulas themselves, I will provide explanations that are like descriptions of the formulas. My approach is to explain how to conceptualize these formulas through images and words, rather than leaving them as mere equations. I believe it's better to understand the meaning of concepts like the Schrödinger equation or the wave function, don't you think? Is Physics Also Reaching Its Limits? Philosophy is a completed discipline. This doesn't mean philosophy is no longer necessary in the world. Rather, the foundational theory of philosophy, its very groundwork, has been finished. With post-structuralism, contemporary philosophy has completed its foundational theory. What remains are applications of philosophy, its history, and its relationship with sociology—the core is finished, and research has shifted to peripheral areas. Therefore, while many universities retain the old department name "Philosophy," what they are actually doing is ethics, which broadly includes philosophy. In the sense that its foundational and core parts are complete, philosophy is a "finished" discipline. But in a slightly different sense, there is another field where the discipline seems to be at a standstill, unable to progress. This is the area that deals with the fundamental parts of physics. Physics, the Champion of Natural Science The foundation of natural science is physics. There are various fields in natural science, such as chemistry, biology, and earth science, offered as high school electives or specialized departments in university science faculties, but physics is the foundation of them all. Within physics, the areas that deal with fundamental aspects, such as particle physics and cosmology, form the core of the discipline. Applied fields like electromagnetism, thermal-statistical mechanics, and fluid dynamics may exist, but the foundational theory of physics asks the ultimate questions: What is electromagnetism? What is heat? What is force? What is a fluid? The Foundation of Physics is Made of Quantum Theory Quantum mechanics is famous, but there are also relativistic quantum mechanics, which incorporates the special theory of relativity, and further developments like quantum field theory. Quantum theory provides a detailed picture of the microscopic world that forms the basis of our universe. It successfully describes the behavior of electrons, protons, neutrons, and other elementary particles that constitute atoms, and it offers a model more fundamental than atomism, known as the Standard Model of particle physics, which explains what elementary particles the world is made of. Furthermore, while these are theoretical systems that do not include gravity or general relativity, numerous unified theories have been proposed, such as string theory, loop quantum gravity, and M-theory (a more generalized and extended version of string theory), which do incorporate general relativity and gravity. There are several stances. Modern physics, excluding the most cutting-edge research, is composed of quantum field theory and the Standard Model of particle physics. The central concept is the "field," and particles are seen as excitations, or "bits," that arise from parts of this field. Elementary particles can be considered parts of a field. There are various fields in the universe, and each gives rise to a specific type of elementary particle. These particles interact with other fields and the particles that arise from them. In this way, all fields and particles are interconnected, whether directly or indirectly. The current Standard Model and quantum field theory have been refined through verification, experimentation, and theory-building. However, because they cannot yet explain everything, such as the handling of gravity and general relativity, various theories are being developed to provide a complete explanation. There are diverse approaches: theories that attempt to explain all fields as arising from a single fundamental field; theories like string theory, which posit that tiny strings and their vibrational modes explain everything; and approaches that use group theory to describe the interactions of particles and fields, attempting to create a unified description by constructing larger, more extended groups, which in the process might predict new fields based on the symmetries of nature. In this article, I will focus on explaining quantum mechanics and quantum field theory within the broader scope of quantum theory. I will also touch upon relativistic quantum mechanics, which combines quantum mechanics with the special theory of relativity. The Dilemma in Physics: The Limits of Verification and Measurement Unlike the statement "Philosophy is a completed discipline," we cannot say "Physics is a completed discipline." However, it is in a state of gridlock, finding it difficult to advance. This is related to the limits of verification and measurement. To artificially observe phenomena in the microscopic world, scientists conduct collision experiments using particle accelerators to see what phenomena occur and whether new elementary particles can be found. However, there is a limit to the energy levels that humans can currently achieve with particle accelerators, meaning we can only observe phenomena within that range. The results from such observations are often well-explained by existing physical theories. Another approach is to observe phenomena occurring in the vast universe. This involves using astronomy to observe black holes or using detectors like Japan's Super-Kamiokande to capture cosmic rays in an attempt to measure new phenomena or particles. Despite various innovations, there are practical limitations due to budgets and other "real-world" adult circumstances. For these reasons, even if we can create theories that comprehensively explain known phenomena and measurement results, further progress is difficult. This is the current situation for the foundational part of physics. Of course, applied physics—the various sciences in university science departments, other fields of physics, and applications in engineering, technology, and industry—is making remarkable progress. But a sense of stagnation hangs over the effort to delve deeper into the foundations of physics itself. Still, the possibility of a breakthrough cannot be denied. A Brief History of Physics Physics is the foundation of natural science. One might even say it is the foundation of all science, but bridging the gap between the humanities and physics is still a long way off. Philosophy is a humanistic science. From the perspective of modern philosophy, quantum mechanics can be seen as another model of ontology and realism, alongside the classical mechanical worldview. What we learn intuitively during our development, or within the scope of primary and secondary education, is this classical mechanical worldview. It is built upon the concepts of time, space, and matter from figures like Galileo, Newton, and Descartes. Einstein's theory of relativity changed the concepts of spacetime, mass, and energy, but it can be seen as an extension of classical mechanics. By the way, the "dynamics" in mechanics can be read as "change." In a word, mechanics can be called the study of change. Physics itself, in a word, can be called the study of the changes of various things. Therefore, both classical mechanics and quantum mechanics can be said to be studies of the changes of things. The difference is that classical mechanics is based on a classical framework, while quantum mechanics is based on a quantum theoretical framework. Thus, if you want to study quantum mechanics, it is useful to know quantum theory as a general theory. The Word 'Quantum' Doesn't Encompass All of Quantum Theory Judging by the term "quantum theory," one might think it's simply the idea of viewing things as "quanta." That's not wrong, but as quantum theory developed, many things were discovered that differ from the conventional wisdom of classical physics. We need to consider these as well. In other words, I think it's fair to rephrase classical theory and quantum theory as modern physics and contemporary physics. Visually speaking, just as calculus (differential and integral calculus) created classical mechanics, classical mechanics tends to view nature in terms of continuity. In contrast, quantum theory has aspects that view nature discretely. For example, a value that is continuous in classical mechanics might have a minimum value in quantum mechanics or can only take on integer or rational multiples of that minimum. However, the word "quantum," as in "quantization," has come to have a much broader range of meanings as quantum theory has developed. This is because phenomena completely different from classical physics have been discovered. For example, in quantum theory, an electron has wave-like properties. In classical theory, an electron is treated as a particle and does not have wave-like properties. For instance, in classical physics, light is a wave and thus has an image of continuous extension. But in quantum mechanics, light is both a wave and a particle, so it is an entity without continuous extension, and its existence is not continuous. This is the classical physics way of thinking: waves and objects (particles) are separate things. Waves can be superimposed. Conversely, you can define a wave as something that can be superimposed. Because they can be superimposed, waves with periodic phases, like sine waves, can create interference patterns. Objects, whether they are point particles or rigid bodies with volume, cannot be superimposed. Therefore, interference should not occur. In quantum theory, electrons do exhibit superposition. That is, they interfere and create interference patterns on a screen. This means that electrons possess both the properties of classical particles and the wave-like property of superposition. The key point is that this applies not only to electrons but to all elementary particles. To explain this dual nature of particles and waves that all particles possess, equations and functions are used that are modified versions of those in classical mechanics. Explaining these equations and functions is the first primary goal in understanding quantum mechanics. The second major goal is to modify the equations and functions for particles to create equations and functions that describe a field itself. And then, to interpret them. At this point, the protagonist of quantum theory shifts from elementary particles to fields. An elementary particle is nothing more than a part of a field that arises, disappears, interacts, or interacts with other fields and particles at various places and times. But for now, it's best to start by explaining the simplest conceivable model: the Schrödinger equation, which describes the behavior of an electron "orbiting" a proton, and its solution, the wave function. Schrödinger's Quantum Mechanics Many people may have encountered quantum mechanics in high school physics or as a general education course in a science-related field. Those in the humanities or in university departments unrelated to physics may have never taken a course on it. However, it is likely touched upon in chemistry, biology, and even earth science. Quantum mechanics can be expressed in various ways. The most famous are the Schrödinger equation, Heisenberg's matrix mechanics, and Feynman's path integral formalism. The most familiar is probably the Schrödinger equation and its solution, the wave function. I will use this for my explanation. The Schrödinger equation and its solution, the wave function, are used to describe the state of an electron bound to a single proton. In other words, they are for observing the various physical quantities of the single electron in a normal hydrogen atom. In classical mechanics, you would set up an equation to find the motion of the Moon around the Earth, just as you would for the Earth around the Sun. This is a differential equation. Classical mechanics was originally an invention, or discovery, of Newton's. Newton himself, in his famous book Philosophiæ Naturalis Principia Mathematica, described it using Euclidean geometry. He avoided using the calculus he had invented. However, calculus, and more broadly, analysis, along with astronomy and classical mechanics, developed at a tremendous pace, and problems in mechanics came to be solved using analysis. By the way, think of the "dynamics" in mechanics as the cause of change, and "mechanics" as the study of change. The field of study that uses analysis to handle mechanics is called analytical mechanics. This gave birth to a discipline that solves mechanical problems using analysis and algebra. The problem of mechanics is reduced to setting up a differential equation and finding its solution, which is a function. Classical mechanics does not contradict quantum mechanics. You can solve problems of classical mechanics using quantum mechanics. In other words, quantum mechanics is an extension and generalization of classical mechanics. However, when describing the motion of microscopic particles like electrons, strange behaviors are observed that do not appear in classical mechanics for celestial bodies like the Moon or Earth. Physics needs to create theories that do not contradict measured physical quantities. Whether it's an electron, a proton, or a photon, anything that exists in the microscopic world has both particle and wave properties. A theory needs to be constructed to explain both of these. Two successful explanations for the behavior of an electron bound to a proton were Schrödinger's wave mechanics and Heisenberg's matrix mechanics. It has since been shown that both are just different ways of expressing the same thing. To explain Schrödinger's method, it takes the approach of solving a certain equation to find its solution, a function, much like in analytical mechanics. This solution is called the wave function and contains information about the electron's various states, such as its position, momentum, and energy. In physics, observable quantities, whether position or momentum, are called physical quantities. In classical mechanics, it is possible to measure a definite value for a physical quantity, excluding errors. You simply solve a differential equation, get a function, and plug in the parameters; theoretically, that's the end of it. There might be variations in experiments, but those are considered unavoidable dispersions or errors due to the limitations of the measurement method, which doesn't perfectly match the theory. This is deterministic because it's represented by a simple equation and its solution. In quantum mechanics, that changes. A particle also has wave properties. The nature of a wave is that it can be superimposed and has an unbounded extension. Particle nature, whether viewed as a point or a rigid body with extension, has a clear boundary, and different particles cannot overlap. In classical mechanics, having both particle and wave properties is a contradiction. A particle is a particle, and a wave is a wave; they are separate things. The same entity cannot have both properties, and each is described by its own method. In quantum mechanics, even when we use the word "particle," it also has wave properties. Therefore, a different concept is needed to represent it, and the equations have a different structure. The things that are observed and measured are called physical quantities. Position and momentum are examples. In quantum mechanics, to obtain the physical quantities of an electron, one solves the Schrödinger equation to get the wave function and then applies something called an operator to it. This mechanism allows us to predict the possibilities of the observed results. This separation of the wave function and the operator is the foundation of quantum mechanics. By applying an operator to the wave function, you can simultaneously obtain information about the possible values a physical quantity can take and the probability of that physical quantity being observed. When a measurement is actually made in an experiment, one of those values is measured. And the frequency with which that value appears depends on its probability—some are more likely, some are less likely. Wave Function (State Vector) and Operators If classical mechanics involves solving an equation, getting a function, and plugging in numbers to get a definite physical quantity, quantum mechanics requires one or two extra steps. This arises because, in quantum theory, all existence has both particle and wave properties, a more complex ontology than the classical standpoint. This brings about a transformation in ontology that goes beyond just particle-wave duality or viewing physical quantities discretely. The structure, or the operating system, if you will, is different between classical theory (including the classical theory of waves) and quantum theory. In quantum mechanics, you obtain a physical quantity by applying an operator to a wave function. Mathematically, that's what happens, but its interpretation is crucial. Often in quantum mechanics, an electron is described as something like a cloud with an existence probability. When it is measured in a verification experiment, only a single value is measured. The cloud is not measured. Since it's a single value, it's perceived as if one measured the physical quantity of a particle. By repeating the measurement many, many times, you start to get an outline of this cloud-like mode of existence. This is a common way of understanding quantum mechanics when first learning it. The important question here is: why does it exist in the form of a cloud or mist? This is related to the superposition principle. You might have heard this term before; it's also related to Schrödinger's cat. A decisive difference between quantum mechanics and classical mechanics is the measurement problem. Whether in classical or quantum mechanics, at the moment of measurement, a specific physical quantity emerges, and its value is determined. In classical mechanics, the underlying assumption is that even when not being measured, the particle exists in a way that follows the equations and functions. In quantum mechanics, this premise is completely different. In quantum mechanics, the thinking is that "except at the single point of measurement, the particle (sometimes called a wave packet to emphasize its wave nature) simultaneously takes on all conceivable, possible states." The possible states a particle can take may be few or infinite. It takes on all these states simultaneously. This "taking on all possible states" is the key point. Although I use the word "particle," the term "wave packet" is sometimes used as a compromise to emphasize its wave nature. All these possible states are superimposed, and because of their wave nature, they interfere, strengthening or canceling each other out like interference fringes. For those who have studied the electron orbital theory of molecules or the mechanism of covalent bonds in organic chemistry, you probably learned that the electron cloud or mist doesn't exist uniformly but has denser and thinner parts. This is described by concepts like s-orbitals, p-orbitals, and sp2 hybrid orbitals. The electron that forms a hydrogen atom, which can be said to be bound to a proton, also doesn't exist as a uniform cloud or mist but exists with varying probabilities (densities) at different positions. This is due to the superposition principle (a principle, which in mathematics would be an axiom, the highest grade of law) and its wave nature (being able to be superimposed and having a phase). The Measurement Problem At the moment of measurement, the superposition temporarily collapses, and a measured value, a physical quantity, is determined. In the case of Schrödinger's cat, the cat exists in all states until it is measured. The moment it is measured, its state converges to a single one. Various states are possible, but it will be one of the conceivable, possible states. When measured, it might be dead or alive, but its life-or-death status is decided upon measurement. This is a strange feeling from a classical perspective. Some might not just feel it's strange but think it's impossible. However, that's what quantum theory is. Einstein's reluctance to accept quantum theory, finding it hard to believe that the moon he wasn't looking at might not exist in the night sky, is a similar sentiment. "All possibilities exist simultaneously, with varying degrees of probability"—this is the way of thinking, or rather the principle and philosophy, of quantum theory. As I will explain in the section on quantum field theory, it is possible to formulate quantum theory in a way that expresses the principle of least action from classical mechanics. This is called Feynman's path integral, and it too is based on the idea that all possible paths are superimposed; many paths cancel out, but the remaining paths ultimately reveal the physical laws. There is a line in The Brothers Karamazov: "If God does not exist, everything is permitted." In quantum mechanics, it goes further than being permitted; the quantum mechanical way of thinking is that "all possible states must be realized simultaneously according to their degree of probability." This brings up the question: "What is a measured value?" Some god or natural law dictates that when not being measured, all possible states coexist, but the moment a measurement is made, they converge to a single point. Because it converges to a single point, classical mechanics, or our natural, intuitive perception developed through growth, perceives the world as a classical world-picture (a Cartesian or Newtonian world). According to quantum theory, a pure substance—a particle or rigid body without wave properties—does not actually exist. The Procedure of Quantum Mechanics In quantum mechanics, measuring a physical quantity means applying an operator corresponding to the desired physical quantity to the wave function. This yields a probability amplitude, from which the probability of a certain state being measured can be determined. If you want to find the most expected measurement value from a measurement, you can also calculate the expectation value. All of these are performed through mathematical procedures. Quantum mechanics represents these using complex numbers and complex functions, and both their absolute values and phases have meaning. The reason they are not simple real numbers is, broadly speaking, because of the superposition principle and the fact that existence is fundamentally also a wave. Relativistic Quantum Mechanics I wrote that quantum theory includes classical mechanics when scaled up, but the quantum mechanics of Schrödinger, which only describes the behavior of an electron in a hydrogen atom, does not represent all of classical mechanics. For example, it does not take special relativity into account. Nor does it consider general relativity. When a particle's velocity approaches the speed of light, not only classical physics but also quantum mechanics must obey the special theory of relativity. For this reason, a scientist named Dirac created relativistic quantum mechanics, which incorporates special relativity. This is an extended version of Schrödinger's quantum mechanics. By finding the set of functions that are solutions to the Dirac equation (called a spinor) and applying operators to it, physical quantities are determined. The solution to the Dirac equation is a four-component spinor, consisting of four functions, and these four components have meaning. They predict the existence of up and down spin, as well as the antiparticle of the electron, the positron. The existence of spin was already anticipated, but in relativistic quantum mechanics, spin is derived naturally. The Standard Model of Particle Physics As research into the microscopic world progressed, various elementary particles were discovered. In the mid-20th century, many elementary particles were found through particle collision experiments using accelerators. Theories were then created to explain them. Sometimes, a theory predicts the existence of a certain elementary particle, which is later confirmed by experiment. In this way, current physics has created a "specimen collection" of elementary particles called the Standard Model of Particle Physics. It's unknown whether these elementary particles are the smallest and most fundamental constituents of everything, and it has been debated that we may not be able to go further with current technology and observation levels. But, as it happens, or perhaps perfectly, the Standard Model is an exceptionally good model. If you add to this not the classical field but the theory of the quantum field, quantum field theory, your study of quantum theory, or what is commonly called quantum mechanics in a broad sense, will reach a milestone. Particles and Fields When one learns classical mechanics and then begins studying quantum theory with the Schrödinger equation, an preconception tends to arise that quantum theory is about describing the changes of particles, such as their momentum or position. This is a very difficult problem and one that often occurs when progressing from elementary to higher education. For example, you don't teach set theory or category theory to elementary school students when teaching mathematics. You start with arithmetic, the four basic operations. Even before that, you teach numbers. Trying to teach set theory or category theory to elementary schoolers would probably be not only ineffective but also harmful. This is likely related to the structure of the brain. The same goes for physics. It is probably a mistake to start teaching physics with quantum theory in middle or high school. The correct way is probably to teach classical physics first. However, this is sometimes like teaching a lie. In Buddhism, there is a convenient word for this: hōben (expedient means). "A lie as an expedient means"—this is primary and secondary education. It's not that higher education always teaches the truth; in fact, for science, the "truth" may be something like Kant's "thing-in-itself" or Plato's "idea," forever unattainable. Nevertheless, from the perspective of the standard curriculum in higher education, it can sometimes seem like elementary and middle schools are teaching falsehoods. Therefore, it might be fine for primary and secondary education to be provided in a form that is familiar to children, but this can become a major obstacle to learning when they study the content of higher education. This is one reason why university-level mathematics and physics feel difficult. Children's education starts with what is intuitively easy to understand, but this "intuitiveness" can be a hindrance in many ways, not just in the educational content. When learning quantum mechanics, the common sense of classical mechanics can be an obstacle. When learning quantum field theory, the common sense of quantum mechanics can be an obstacle. If quantum mechanics describes a specific elementary particle like the electron, quantum field theory focuses on the field from which that electron originates. The electron is something that arises from the electron field and is merely a part of the electron field. A part of the electron field is excited and becomes an electron. Even if it is "excited," it doesn't become something else; the electron is still part of the electron field, and the electron field remains. In fact, elementary particles are created and annihilated. Or they can change into other elementary particles. This is true both experimentally and theoretically. I mentioned electrons and positrons in the section on Dirac; particles and antiparticles can interact and become other elementary particles. What you first learn in quantum mechanics is that the particle created when the orbit of a hydrogen atom transitions is a photon. You probably learned about alpha decay, beta decay, and gamma decay in high school. Alpha decay is a type of nuclear fission where energy is released. Helium is produced, but photons are also created as a by-product. Since photons are also elementary particles, the creation of elementary particles occurs. In beta decay, electrons and electron antineutrinos, or positrons and electron neutrinos, are created. Both are elementary particles. Photons can also be created as a by-product here. In gamma decay, photons are produced. This means that through interactions and other processes, elementary particles can change into, be created as, or be annihilated into other elementary particles. Since physics is the study of matter, spacetime, and thus the world and the universe, it needs theories, concepts, and tools to explain all of these things. In Schrödinger's quantum mechanics, time and space were already givens, and the existence of protons and electrons was also a given. That is, they were premises. For physics to develop, it needs theories and ideas that can explain the premises themselves, not just take them for granted. For this and other reasons, a new theory was created by positing quantum fields—the source of elementary particles. It's a strange thing to say, but while in classical theory energy can be thought of as something vague, in quantum theory, it can sometimes be easier to think of energy = particle. This isn't just about classical mechanics; in special relativity, too, it might be good to see energy = mass, where mass is a collection of particles, which is a collection of energy. Elementary Particles and Particles I have used the words "particle" and "elementary particle." Even when I say "particle," in quantum theory it also has wave characteristics, so if you want to emphasize that, you could use words like "wave packet" or "oscillator." A particle, for example, a molecule or an atom, can be divided into smaller parts. A methane molecule, for instance, is made of hydrogen, carbon, and electrons. An oxygen atom or molecule is made of one or two oxygen atoms and electrons. An atomic nucleus can be like hydrogen, with just one proton, but there are also hydrogen atoms with one proton and one neutron. Other atomic nuclei are usually made of multiple elementary particles called protons and multiple elementary particles called neutrons. In addition, ordinary atomic nuclei are made of gluons, an elementary particle responsible for the "strong interaction" that binds protons and neutrons together in the nucleus. An elementary particle, literally meaning the "element of a particle," is the smallest unit of a particle, a more fundamental entity that forms particles. Both electrons and photons are elementary particles. In ancient Greek atomism, the atom was considered the ultimate reality. However, in the case of elementary particles, "ultimate" does not mean ultimate reality in that sense. Elementary particles can be annihilated, created, and interact to produce other elementary particles, or they can produce other elementary particles and be annihilated themselves. If an elementary particle can change into another elementary particle, it is difficult to call it an ultimate reality in the sense of ancient Greek atomism. An ultimate reality would not change into or be annihilated by something else called an ultimate reality. The Standard Model of Particle Physics and Quantum Field Theory There are steps in the development of quantum theory. It started with a model like an electron orbiting a single proton, as described by the Schrödinger equation. The existence of the proton and the electron is assumed as a premise. Relativistic quantum theory is an extension of Schrödinger's model that considers the special relativistic effects that occur when an electron's speed is close to the speed of light. As a result, it predicted the existence of up and down spin as degrees of freedom and the existence of antimatter particles, the electron and the positron. After that, many things happened, but from around the 1950s, particle accelerators were built, and it was discovered one after another in experiments that colliding particles could create different particles. From this, a theory was created that particles like protons and neutrons are not elementary particles but are made of more fundamental elementary particles called quarks. The Standard Model of Particle Physics is something that has been built up through repeated experimentation and theory. It lists all the elementary particles currently measured in experiments and also predicts the existence of other, yet-to-be-found elementary particles. Furthermore, an idea emerged that elementary particles are not the fundamental source, but rather that they are excitations of a part of something called a "quantum field." For example, when the electromagnetic field (photon field) is excited, a photon is produced. When the electron field is excited, an electron is produced. The idea of a "field" also exists in classical physics; you may have learned about the gravitational field, electric field, magnetic field, and Maxwell's electromagnetic field, which unified the latter two. A quantum field is a new concept of a field in quantum theory that has some differences from a classical field. Whether it's the Schrödinger equation or the Dirac equation, they are still theories based on classical physics, extending it by turning the Hamiltonian into an operator or incorporating special relativity. The development from a classical field to a quantum field may have a certain inevitability, but it is a paradigm shift with a huge impact. It is a shift from quantum mechanics, where particles are the protagonists, to quantum field theory, centered on fields. The mathematical formalism for handling the entire field is surprisingly similar. If quantum mechanics predicts physical quantities by applying an operator to a wave function, quantum field theory can predict physical quantities—that is, the probability of a certain value appearing or its expectation value—by applying an operator to something called a state vector. In the case of quantum field theory, there is a field operator that is the source of all operators, from which creation and annihilation operators can be derived, and furthermore, all other operators can also be derived. The existence of creation and annihilation operators means that the excitation of elementary particles can also be expressed by operators. Thus, the field is central, and the elementary particles that arise from it are the result. Furthermore, it can describe the excitation of multiple elementary particles, and it also makes it easier to explain the interactions between particles. This is called quantum field theory. These two ideas, the "Standard Model of Particle Physics" and "Quantum Field Theory," represent a pinnacle of quantum theory. It is a highly complete theory, and regarding the Standard Model, the Higgs boson, which it predicted, was discovered not long ago, as was reported in the news. A Deeper Look into Quantum Field Theory In quantum field theory, there is a field for each elementary particle. A certain elementary particle and its field can interact with other types of elementary particles and their fields. Of course, there are also cases where they do not interact. However, when viewed as a whole, the elementary particles of the Standard Model and their fields are indirectly connected even if they do not interact directly. There is no field that is isolated and does not interact with other fields, either directly or indirectly. The Standard Model is not just a list of elementary particles; it is a catalog that also includes these direct and indirect interactions. The procedure for formulating quantum field theory is known. This is called canonical quantization. In quantum field theory, first, operators are obtained by "operator-izing" the analytical mechanics of classical mechanics. Next, a rule called the canonical commutation relation is introduced, following the model of Poisson brackets in classical mechanics. This rule is a principle, and from it, the uncertainty principle and the conjugate relationships of physical quantities can also be understood. Furthermore, the commutativity or non-commutativity of conjugate physical quantities leads to conservation laws. For example, they are derived in the form of Noether's theorem, leading to the conservation of energy with respect to time, the conservation of momentum with respect to translational motion, and the conservation of angular momentum with respect to angle. Incidentally, unlike in classical physics, conservation laws are not always absolute. For example, the law of conservation of energy may not hold for short periods of time. This is because time and energy are in a trade-off relationship due to the uncertainty principle. Next, the state vector is determined. Broadly speaking, this completes the mathematical foundation of quantum field theory. You can think of the state vector as something similar to the wave function. Or rather, the wave function is a type of state vector. And again, physical quantities are obtained by applying operators. You can think of applying an operator as the mathematical equivalent of the act of "measurement" in a verification experiment. The result, depending on what physical quantities are chosen as the basis vectors, is expressed as a vector space over probability amplitudes, with the existence probability of the eigenvalues as coefficients. The square of the absolute value of the probability amplitude is the so-called probability (also called probability density), so the coefficients of the basis vectors express the probability (and phase, since it's a wave) of that physical quantity. If the eigenvalues are discrete, this takes the form of a vector as learned in linear algebra; if the eigenvalues are continuous, it takes a form expressed by an integral. In an actual experiment, only a single point may be measured, but mathematically, the probability of that measured value appearing is expressed. From there, the expectation value of the measured value that will result from the measurement can also be calculated. Weaknesses of Quantum Field Theory Quantum field theory is an excellent theory. Regarding the Standard Model of Particle Physics, due to the limits of experiments and observations, there may be even smaller, more fundamental elementary particles than what are currently called elementary particles, but for now, we are managing without them. In other words, it has succeeded in explaining many aspects of the world's existence without contradiction, using only the currently recognized elementary particles. However, it also has weaknesses. For example, quantum field theory uses a classical, or rather, a special relativistic spacetime, and it is a theory built upon that. This is incompatible with general relativity. General relativity expresses the relationship between mass, gravity, and space through the curvature of space. Quantum field theory does not incorporate this curvature. From another perspective, its explanation of gravity is insufficient. Force can be defined as the cause of change. Mechanics is the study of change. In quantum theory, it might be better to rephrase force as interaction. There are four forces: the electromagnetic force, the strong interaction, the weak interaction, and gravity. The first three forces can be incorporated into the Standard Model of Particle Physics as photons, gluons, and bosons, respectively, but the graviton cannot be successfully incorporated. From this, a unified theory, or a grand unified theory, that unifies everything has been considered, and several have been proposed. For example, just as Maxwell unified the electric and magnetic fields into the electromagnetic field, there is the idea that there might be a field that encompasses all fields. Another idea is string theory, or superstring theory, which attempts to understand all elementary particles and fields in a unified way through the vibrational modes of very small strings. There is also an approach like an extension of gauge theory, which aims to encompass everything with a larger group that includes the Standard Model, as the transformation of particles due to interaction can be described by group theory, which is the study of symmetry. While these can explain various things as grand unified theories, the problem is that verification is difficult. Even with accelerators, there are realistic limits to the scale of the facility and the energy that can be produced, so it seems various efforts are being made in the direction of searching for the key to verification through cosmic observations and other means. Quantum Theory and Philosophical Ontology and Epistemology As I wrote at the beginning, quantum theory, from a modern philosophical perspective, can be understood using either realism or structuralism. This is no different for classical mechanics or classical mathematics. It's just that older ways of thinking were basically only realist, with the exception of the Mahayana Buddhist theory of emptiness (Kū). Quantum theory is a new way of thinking in physics, but it is a branch of natural science. Since natural science itself has a tendency to unconsciously presuppose realism, it's safe to say that quantum theory is also treated as a type of realism. However, even if we call them both realism, classical physics and quantum theoretical physics have quite different flavors. Classical mechanics isn't about getting a deterministically fixed answer from a system of equations, even without going as far as analytical mechanics. The mathematical formulas are a bit complex, or rather, have a strange form, but each part has meaning: the wave function or state vector that represents the state, and the operator that acts on it. A quantum theoretical state, before measurement, assumes all possible states. It might be a bit different, but one could express this as a cloud of probability. Through measurement, such as experiments or observations, at that instant only, all possible states converge, collapse, and are determined into one state. Just because it was determined does not mean it was that way before the measurement; this is not possible in quantum mechanics. It is also different from our everyday sense that we cannot know the past. Until it was measured, it was actually taking on all possible states simultaneously, with their respective probability densities and phases. This is the ontology and epistemology that quantum theory possesses, which is different from classical theory. In modern philosophy, or in Buddhism, post-structuralism and the Middle View (Chūgan) are meta-cognition; they are the OS. Structuralism, the scientific way of looking at things, the classical physical way of looking at things (since physics is the foundation of natural science), and the quantum theoretical way of looking at things are applications. The practical use of modern philosophy is to increase the number of applications. In other words, it is to enable oneself to have various ways of seeing and thinking. Or, it is to master various ways of processing information and to be able to analyze a subject with fundamentally different ways of thinking. For that, it is important to increase the number of applications. In that sense, I have tried to explain quantum theory, which is a more fundamental and generalized way of thinking that embraces classical physics, yet is not widely known.

A Simple Explanation of Quantum Theory: Another Way of Philosophical Existence

A Simple Explanation of Quantum Theory: Another Way of Philosophical Existence Quantum Theory as Another Model of Realism Modern philosophy can be broadly divided into structuralism and post-structuralism. Structuralism corresponds to the Buddhist concept of emptiness (sunyata), while post-structuralism aligns with the Buddhist concept of the middle way or Madhyamaka philosophy. Strictly speaking, post-structuralism minus structuralism equals the middle way or Madhyamaka, which in short means observing and relativizing all ways of thinking through meta-cognition. Examples of ways of thinking include classical physics or classical mathematical realism, and structuralist ways of viewing phenomena. Besides classical mathematical and physical realism, there is also a quantum theoretical way of viewing phenomena. Philosophy, narrowly defined, consists of ontology (the study of existence) and epistemology (the study of knowledge). The form of realism we intuitively learn before higher education is Cartesian, or modernist, realism and epistemology, exemplified by classical physics and mathematics. Quantum theory refines classical physics and offers an inclusive viewpoint that encompasses classical physics. It can be viewed either as realism or structuralism, but since physics itself tends toward realism, it is conventional to regard quantum theory as realism. Classical physics, similarly, can be viewed structurally, but because it inherently assumes natural realism, it's commonly regarded as realist. Here, rather than delving into philosophical details, I'll explain quantum theory simply, without equations, in words alone, as it is beneficial for those accustomed only to classical perspectives. Before Learning Quantum Theory For those eager to jump into quantum mechanics or quantum field theory, I apologize, but first, let me briefly outline the current state of physics. Though quantum theory is described mathematically, understanding its meaning, even broadly, is essential. It is crucial that concepts resonate clearly through natural language, imagery, or narrative. The Limits of Physics? Philosophy, foundationally, is complete—not unnecessary, but its fundamental issues have been addressed, notably by post-structuralism, leaving only applied or historical philosophical studies. Physics, particularly fundamental physics, however, faces challenges. Though foundational, physics now struggles to progress significantly due to experimental and measurement limits. Physics as the Pillar of Natural Sciences Physics underpins all natural sciences, including chemistry, biology, and geology. Fundamental physics deals with particle physics and cosmology, addressing essential questions such as the nature of electromagnetism, heat, forces, and fluids. Quantum Theory as the Foundation of Physics Quantum theory includes quantum mechanics, relativistic quantum mechanics (which combines quantum mechanics and special relativity), and quantum field theory. Quantum theory describes microscopic worlds like atoms, electrons, protons, neutrons, and other particles, providing a fundamental model beyond classical atomism. Quantum field theory and the Standard Model of particle physics currently dominate physics, describing particles as excitations from underlying quantum fields. While successful, these theories still cannot fully integrate gravity and general relativity, leading to various proposed unified theories, including string theory and loop quantum gravity. Dilemmas in Physics: Experimental and Measurement Limits Unlike philosophy, physics hasn't concluded but faces significant barriers due to experimental limits. Particle accelerators and cosmic observations have practical limitations, restricting further theoretical developments. Although technological applications thrive, foundational physics searches for breakthroughs. A Brief History of Physics Physics, central to natural sciences, remains distant from connecting seamlessly with humanities. Quantum mechanics offers another ontology or realism model alongside classical mechanics. While classical physics, extending from Galileo and Newton, deals with changes in phenomena, quantum mechanics offers a fundamentally different approach. "Quantum" Does Not Capture All Quantum Theory Initially, quantum theory viewed phenomena discretely, contrasting with classical continuity. However, quantum phenomena like electron wave-particle duality challenge classical concepts significantly. Classical particles can't exhibit wave interference; electrons in quantum theory can, displaying both particle and wave properties. Schrödinger’s Quantum Mechanics Quantum mechanics, particularly Schrödinger's equation and wave functions, describes electron states around protons in atoms, differing fundamentally from classical orbital mechanics. Quantum theory treats particles probabilistically, with outcomes determined only upon measurement. Wave Functions and Operators Quantum mechanics uses wave functions and operators to predict physical quantities probabilistically. Unlike classical physics' determinism, quantum states exist as probability clouds until measurement collapses them to specific outcomes. The Measurement Problem Quantum theory posits simultaneous existence of all possible states until measured, illustrated by Schrödinger’s cat thought experiment. Measurement collapses possibilities into reality, a concept challenging classical intuition. Quantum Mechanics Procedures Quantum mechanics involves applying operators to wave functions to predict outcomes probabilistically, highlighting complexity beyond classical deterministic approaches. Relativistic Quantum Mechanics Dirac incorporated special relativity into quantum mechanics, introducing concepts like spin and antiparticles, enhancing quantum theory’s explanatory power. The Standard Model of Particle Physics Particle accelerators discovered many particles, explained by theories like the Standard Model, which catalog particles and interactions, successfully predicting particles like the Higgs boson. Particles and Fields Transitioning from particle-focused quantum mechanics to field-centered quantum field theory involves treating particles as excitations of underlying quantum fields, allowing dynamic particle creation and annihilation. Quantum Field Theory Quantum field theory uses state vectors and operators analogous to quantum mechanics, offering a sophisticated framework explaining particle interactions comprehensively. Limitations of Quantum Field Theory Despite its success, quantum field theory struggles to incorporate gravity, prompting proposals for unified theories like string theory and gauge theories, though experimental verification remains challenging. Quantum Theory and Philosophical Ontology and Epistemology Quantum theory can be viewed through realism or structuralism, differing significantly from classical realism. Quantum states encompass multiple possibilities simultaneously, collapsing into definite outcomes upon measurement, representing a fundamental philosophical shift. Thus, quantum theory represents a richer, broader, yet less familiar philosophical approach than classical physics, deserving greater understanding and application.

The Japan Boom (Japanization), the Revival of Buddhism, and the Relationship Between Modern Philosophy, Religion, and God

For a Deeper Understanding of Japan and Buddhism There is a Japan boom happening right now. Perhaps due to a human desire for the exotic and the novel, concepts like Shinto are often used to understand Japanese culture and its people. The Japanese are sometimes described as a nation that accepts anything, exemplified by the saying, "Funerals are Buddhist, but weddings are Christian." When people seek a reason for this, it's often explained away with phrases like "the eight million gods" (yaoyorozu no kami). (For the record, "eight million" is just a poetic way of saying "countless.") However, it's impossible to understand Japan with this perspective alone. Another theory suggests the cause is Japan's nature as an island nation, which makes it conservative and prone to accepting and preserving everything that arrives. This might also be true. But even that is not a sufficient explanation. In truth, Japan has another core philosophy. That philosophy is Buddhism. Specifically, it is the Buddhist ideas of Kū (Emptiness) and Chū (the Middle View). In the Tendai school of Buddhism, these are collectively known as the Santai (Three Truths). Some may know this from the words of Nichiren, who said, "All that is important in Buddhism is the Three Truths and the Lotus Sutra." These concepts are difficult and cannot be understood immediately. They often don't appear on the surface of Japanese culture, and even when they do, they frequently go unnoticed. Yet, like an unsung hero, a stagehand in black, or an operating system, this philosophy invisibly supports every aspect of Japanese culture that appears on the surface. Global Misconceptions About Japan Many aspects of Japan are currently experiencing a global boom. It is famous that a wave of Japonisme occurred in France in the late 19th century, influencing the arts. But what is happening now is something like a new Japonisme, occurring on a much wider, global scale across countless fields. There have always been many things said about the Japanese. Regarding religion and faith, they are sometimes called irreligious or atheistic, and at other times, polytheistic. Regarding their national character, they are said to be ambiguous, to not speak their minds clearly, or to have strong conformity pressure. This time, these and many other characteristics are being instantly transmitted globally across various fields via social media, sometimes going viral. It seems that discussions on Japanese culture and the Japanese people, by everyone from laypeople to experts, have greatly increased. A large part of the world is dominated by exclusive monotheistic religions, belonging to a biblical cultural sphere that has undergone modernization and Westernization. It is a culture of logocentrism, which in turn is exclusive of anything outside the Logos. In such a cultural sphere, people are powerfully bound by certain modes of thinking, often on an unconscious level. For example, they cannot imagine a world without God or religion. In medicine, there is a symptom known as agnosia, a failure to recognize or identify objects. This can be seen in relatively common conditions like dementia. Even in the typical development of children, it might be normal to have what could be called "physiological agnosia" or "physiological amnesia." This is a common thought pattern among the world's major forces: Christians, Muslims, and Jews combined. While some developed countries are seeing a rise in secularism, these ingrained thought patterns are not easily shed. That said, the Christian, Muslim, or Jewish identity of these regions is at most 2,000 years old, and in some places, it is a much more recent phenomenon. In the Bible, figures like the Pharisees appeared after the Babylonian Captivity. And while Greek philosophy is said to have emphasized the Logos, it did not take root in the West during the Middle Ages—its existence was largely unknown until after modernization. The Vikings, part of the Second Germanic Migration, were not Christianized. Within Europe, a country like the Grand Duchy of Lithuania was only Christianized toward the end of the Middle Ages, giving it a history of only a few hundred years. But once something is implanted, it is powerful. Few people can notice it, become meta-cognitively aware of it, relativize it, or deconstruct it. Such people try to understand Japan by forcibly fitting it into their own existing mental frameworks, calling it irreligious, animistic, or Shinto. While there is some truth to this, understanding Japan solely through this lens leaves out something crucial. Simply put, while Japan may be a country of Shinto, the perspective that Japan is also a country of Buddhism—and specifically, Mahayana Buddhism—is often missing. Because Mahayana Buddhism is a minority and a special case even within Buddhism, which is itself one of the three major world religions, this point is very easily overlooked. Misconceptions About Buddhism I don't know if it's still the case, but there was a time when the three major world religions were said to be Buddhism, Christianity, and Islam. This may have been because the number three feels complete, or perhaps because Buddhism was more international than Hinduism. There is no "God" in Buddhism. There can be gods, but whether they exist or not is irrelevant to Buddhism. Did people mistake Buddhas and Buddhist statues for gods? It's unclear, but the idea of recognizing Buddhism as a religion did exist in the West. It seems that even now, there are those in the West who accept that a religion can exist without a god. One line of thought was that Buddhism is a religion because, even without a god, it has "enlightenment" (satori), which is achieved through practice. This view is particularly influential among those with knowledge of certain Buddhist traditions. It's the idea that although there is no God, there is a transcendent experience called enlightenment, and by attaining it, one can become a sacred being who has surpassed humanity. Therefore, it's a religion because it has mystical and spiritual aspects. Paul Beck, a 19th-century Buddhist scholar whose work is translated in the Iwanami Bunko series, later turned to Theosophy. Buddhism, and not just its Southern Transmission, is often understood as mysticism, spiritualism, or occultism, sanctifying enlightenment and the enlightened. Perhaps this compensated for Buddhism's lack of a god. The Northern Transmission of Buddhism is different from the Southern Transmission. While their roots are in the original teachings of Shakyamuni Buddha and they share aspects of early sectarian Buddhism, their subsequent paths likely diverged. The Southern Transmission is called Theravada or Hinayana Buddhism, and the Northern is called Mahayana Buddhism, but the words themselves don't hold the meaning. The content of the two is completely different. Southern Transmission (Theravada) Buddhism, found in Sri Lanka, Myanmar, and Thailand, finds a special mystique in enlightenment and the enlightened person. Northern Transmission (Mahayana) Buddhism, found in Tibet, Nepal, Bhutan, Mongolia, and Japan, does not involve becoming a mystical person who undergoes a special qualitative change upon attaining enlightenment. The word for enlightenment in Japanese, satoru, is used to mean "to understand" or "to grasp," and that's exactly what it is. To attain enlightenment means to understand and be convinced of the core ideas of Buddhism. It doesn't mean you become a saint or a hermit, or that you change as a person. You don't take on divinity or sacredness. You simply, truly, understand. In that sense, it is a philosophy. A Brief History of Japanese Buddhism Even within the Northern Transmission, the esoteric (Mikkyō) lineage has some different aspects. What was transmitted to Japan was early and middle-period esoteric Buddhism, while Tibetan esoteric Buddhism is from a later period. It has similarities to Prince Shōtoku's theory of Honji Suijaku (manifestation from the original state), making it syncretic with Shinto. It's a viewpoint that sees all things in the universe as manifestations of Buddha, which can look like animism or polytheism. Religious syncretism is a frequent phenomenon in all religions. But putting esoteric Buddhism aside for a moment, an older form of Buddhism entered Japan directly through China and other routes. From the very beginning of Japan's recorded history, Buddhism entered as part of its history of exchange with the mainland. What is important in Northern Transmission Buddhism are the theories of Kū (Emptiness) and Chū (the Middle View). These entered Japan and form the core of its Buddhism. In Shakyamuni's terms, the Twelve Links of Dependent Origination, impermanence, non-self, non-dharma, and the five aggregates are Kū; the Middle Way is Chū. The person who systematized these core parts of Buddhism was Nāgārjuna, the founder of Mahayana Buddhism. The people who inherited his ideas of Emptiness and the Middle View are called the Madhyamaka school, the originators of Mahayana. For example, in the Jōdo Shinshū school, he is often treated as the first patriarch after Shakyamuni. He is a major figure in the history of world thought, taught in middle and high school social studies textbooks, second only to Shakyamuni himself. Various Buddhist monks from India transmitted these ideas to China via the Silk Road. They were translated into Chinese, their contents were debated, and various schools were formed, but the ideas of the Madhyamaka school became the core theme of every school. The person who summarized the ideas of the Madhyamaka school in an easy-to-understand way was Zhiyi of the Tiantai school. He formulated it as the Santai (Three Truths), consisting of Chū (Middle), Kū (Emptiness), and Ke (the Provisional). The person who studied under the Tiantai school and became the founder of the Japanese Tendai school was Saichō, who built the famous Enryaku-ji temple on Mount Hiei, a famous historical and tourist spot. Almost all schools of Japanese Buddhism, with a few exceptions like those introduced in the Nara period and the Shingon school, trace their roots back to the Tendai school. The founders of the various schools of Kamakura New Buddhism all studied in the Tendai school. The core of all these schools is based on the ideas of Kū and Chū. Even the Jōdo (Pure Land) schools, which seem different, cherish Kū and Chū as their antithesis. The reason the Jōdo schools treated Kū and Chū as an antithesis—and this is the crucial point—is that the concepts of Kū and Chū are too difficult. This is a problem not just for the Jōdo schools, but for Mahayana Buddhism, and indeed, all of Buddhism. "Buddhism is too difficult"—this is the challenge of Buddhism. The "Difficult Problem" of Buddhism "Buddhism is difficult"—this was true even in Shakyamuni's time. His era, much like slightly later periods in China and Greece, was a pivotal time in human intellectual history when various ideas emerged and were actively debated. It was an age when all sorts of new ideas blossomed, distinct from the Vedic Upanishadic philosophy that originally existed in India. Amidst this, Shakyamuni mastered the various advanced ideas of his time, then practiced for another seven years to attain enlightenment. However, it is known that from the moment he attained enlightenment, he was pessimistic, thinking, "What I have realized is too difficult for people to understand, so I should just die now." This "difficulty" is a central theme of Buddhism. "Difficult" means it is difficult to understand and be convinced of. This is a decisive difference from the other two major religions, Christianity and Islam. In these exclusive monotheistic religions of the book, which hold the Bible or the Quran as absolute dogma, "understanding" or "being convinced" is not the issue. For a created human being to claim they can "understand" or "be convinced" of God or the holy scriptures could even be considered a form of heresy, though there are priests, and in Judaism and Islam, rabbis and scholars. In Buddhism, the content of enlightenment is something that can be understood and be convinced of. It's just difficult. At this point, the question "Can Buddhism be called a religion?" will arise. From the perspective of the Abrahamic religions, the conclusion is that "Buddhism is not a religion, but a philosophy." This is a view that has a certain degree of support globally, though I don't know to what extent. The difficulty of Buddhism is no different from the difficulty one might have in understanding other complex ideas or philosophies taught in a social studies ethics class. Specifically, Buddhism is a philosophy with the same content as modern Western philosophy's Structuralism and Post-structuralism. Broadly speaking, Structuralism corresponds to the theory of Kū; Post-structuralism corresponds to the theory of Kū plus the theory of the Middle View, or the Three Truths. Modern thought and modern philosophy are considered difficult, but in some ways, they are more difficult than learning Buddhism. A major problem for Western philosophy is that neither the concept nor the word for Kū exists in the West or in many other regions of the world. But it's not just a matter of a missing concept or word; it's that this is difficult to grasp within a monotheistic, logocentric framework of thought. I think it would be better to just use it as is, like "Tao," but even though it's called one of the three major world religions, Mahayana Buddhism is probably not that well-known around the world. If anything, the Southern Transmission (Theravada) Buddhism is more compatible with the popular spiritualism of the world and tends to be incorporated in forms like mindfulness. Mahayana Buddhism is difficult to understand not just for Westerners, for example, but also for Mahayana Buddhists themselves, and so various methods have been devised to promote understanding. For instance, there is Zen and its related arts. Zen itself was accepted in the West early on; D. T. Suzuki's Zen and Japanese Culture introduced it abroad and influenced culture and the arts. Apple's Steve Jobs is a famous example, but Suzuki was from roughly the same generation as Kitaro Nishida, so his influence dates back to the first half of the 20th century, before and after World War II. The scope of influence is likely vast and probably endless if one were to list it all, but the contemporary composer John Cage was directly influenced by Zen. Zen can be seen as a methodology for understanding Kū and the Middle View, not necessarily relying on speculation alone. Visiting shrines and temples and talking about the "eight million gods" may be fine for shrines, but feeling the "eight million gods" in the rock garden of Ryōan-ji feels a bit off. But perhaps this is how the understanding and reception of culture proceeds, in a jumbled way. Rather, the fact that more people around the world are becoming interested in Japan is a good thing, not just for the Japanese but for people everywhere. Japan is a country where Mahayana Buddhism and its concepts of Kū and the Middle View are embedded as a basic OS. To know Japan is to know Mahayana Buddhism, and furthermore, to know modern thought and modern philosophy. A modern thinker who was clearly aware of this was Claude Lévi-Strauss, and he stated it publicly. He is a key figure in Structuralism and was sharp enough to refute Sartre, so I imagine he was quite brilliant. But even Lévi-Strauss's expression seems somewhat insufficient, and he doesn't fully convey the essence of Japan, or rather, Mahayana Buddhism. That's how difficult the Kū of Mahayana Buddhism is. The Middle View is in some ways simple; recently, the term "meta-cognition" has become understood and accepted, so perhaps that can be used. But for Kū, there seems to be no corresponding concept or word globally. In modern thought, various expressions were used—"différance," "rhizome," "body without organs," "particles," "nomad," "bricolage," "undefined term"—but I wonder if they have been conveyed effectively. I think it would be better to just make Kū a globally understood word as "Kuu." Difficulty Made the History of Buddhism The history of Buddhism has unfolded in a different sense from how other religions have split into various sects. At its core is the principle: "It can be understood, but it is difficult." From the moment Shakyamuni attained enlightenment, he was pessimistic: "It's too difficult to convey, so I should just die." His successor candidate, Sāriputta (written as Shariputra in the Heart Sutra), who understood his teachings, died before him, and he grieved desperately. When Shakyamuni himself was dying, he said, "When I die, my teachings will be lost." After Shakyamuni died, a fundamental split and subsequent minor splits occurred, and various schools divided over the interpretation of his teachings, hence the name "Sectarian Buddhism." Within this, a major division occurred into Mahayana and Theravada Buddhism, and this too was a difference in thinking stemming from the difficulty of understanding. The problem for Mahayana Buddhism was what to do with people who could not understand the teachings. Those who don't understand the teachings cannot attain enlightenment, but Mahayana is a school of thought that seeks to save such people as well. Theravada's approach is, for the time being, to have those who want to attain enlightenment work hard at their practice. Mahayana is the Northern Transmission, and this side is philosophical. Theravada is the Southern Transmission, and since it retains sacredness and mysticism, it is "religious" if you call such things religious. In its native India, Buddhism peaked and then declined, leaving only academies, and was finally destroyed by Muslims. Japanese Buddhism was transmitted from China and the Korean Peninsula. This is written in history textbooks, taught in the early parts of Japanese history. Japanese Buddhism also split in various ways and accepted various schools from China, but when you look at Kamakura New Buddhism, for example, the problem of how to handle the difficulty of Buddhism is still the issue. There are various schools divided by how they handle this "difficulty," such as Zen, which has a strong stance of attaining enlightenment on one's own, and the Jōdo (Pure Land) schools, which have a "the Buddha will save us even if we don't understand" approach. The Japan Boom is a Chance for Buddhism and Modern Philosophy Mahayana Buddhism is difficult, but examples where an old form of Mahayana Buddhism has been preserved, like in Japan, are rare, I think. There is Tibetan Buddhism, but it has been invaded by China. Bhutan, Mongolia, and I'll add Nepal, seem to have less influence. China became communist and secularized. Korea became Confucianized and Christianized; Buddhism remains, but when the Buddhist Goryeo dynasty was replaced by the Confucian Joseon dynasty, the culture of the previous era was radically destroyed. In any case, Japan is a religiously, or rather, a Buddhistically special country. You could say that only Japan has protected it, or has been able to protect it. The OS and Applications of Japanese Culture, Buddhism, and Modern Philosophy Mahayana Buddhism is special. It's more a philosophy than a religion. Its content as a philosophy is the same as modern philosophy. If so, it can be broadly divided into two parts. One is the idea of Kū (Emptiness), which in modern thought is Structuralism. The other is the idea of the Middle View or Chū, or the Middle Way of early Buddhism. This, broadly speaking, is the part of Post-structuralism that remains after subtracting Structuralism. In other words, it is a meta-cognitive perspective. In the theory of the Three Truths, there is Chū (Middle), Kū (Emptiness), and Ke (the Provisional). Ke corresponds to realism in philosophy, and simulation and simulacrum in modern thought. If we classify the relationship between these in terms of the Three Truths or modern philosophy, Chū is the OS, while Kū and Ke are each applications. Chū, the Middle View, or the Middle Way, in modern or modern philosophical terms, means to view all things and ideas with meta-cognition, to see them relatively. It becomes the OS of knowledge. Kū is a structuralist way of grasping objects, a certain way of thinking in ontology and epistemology, and it is one application on the OS. Ke is what we think of as substance or reality, and this too is another application. In Japanese culture, all ideas and religions are applications on the OS of the Middle View, Chū, or Middle Way. Shinto, Taoism, Confucianism, Christianity, Judaism, Islam, atheism, animism—all are just applications. The Abrahamic religions of Christianity, Islam, and Judaism may claim to be the OS themselves, but from a Mahayana Buddhist perspective, they are applications on top of Chū. Applications can be selected, adopted, edited, and modified. It doesn't subscribe to the idea that if you choose one, you must exclude others. Just as a smartphone has many different applications installed, there are various applications on the OS of Chū, and you are free to use them. It's fine to visit a shrine for New Year's, have a funeral at a temple, get married in a church, and follow Confucian etiquette. Chū is a way of thinking that allows various things to coexist. If there are elements of prehistoric culture that are not in that form—from the Paleolithic, Jōmon, or Yayoi periods, for example, animism, shamanism, or totemism—they too are just single apps, so all are acceptable. Well, there may be some apps you don't use much, and probably many you've forgotten about without realizing. When Buddhism was accepted in Japan, there was an exclusive battle over whether to reject it, but before and after that, there haven't been such serious ideological struggles. Even Toyotomi Hideyoshi denied the enslavement of Japanese Christians and the colonization of Japan, but he didn't deny Christianity itself. The Ikkō-shū sect shortly before that was eventually accepted and is now the largest religious force in Japan, though it was politically and secularly defanged. As long as they don't disturb the harmony (wa), applications are allowed to coexist. Kū and Ke can not only coexist but can even be synthesized. This is just like how realism and structuralism are not mutually exclusive and can coexist, so it's fine to stick them together. A good example is that both Euclidean geometry (realist) and Hilbert's formalist geometry can be viewed simultaneously, and they yield the same conclusions. Polytheism, Pluralism, Monism, AI, and a Multi-OS World I've talked about the Middle View as the OS and other ideas as applications. But having only one OS on one computer is an old model. It's possible to have two OSes on a modern PC. You can just switch between them depending on the situation. To talk about the more distant future, as AI progresses, the hierarchical structure of creating an OS first and then building apps on top of it will disappear. A more advanced AI will just have to create an optimized OS for each purpose as needed. In the 19th century, a "computer" referred to the large number of people who performed calculations for functions, astronomy, and actuarial science. Now, computers do those calculations, but many people write code to create a single OS. A famous example of someone who rose through this is Microsoft's Bill Gates. Japan also tried to create its own OS, but around the 1990s, there was a US-Japan trade war, and many things that could have become the core of innovation, like computers, software, and airplanes, were crushed. When AI advances a little more, the need for many people to spend long years creating a single OS will disappear. Even before that, the very concept of what an OS is will become invalid. Even if you're using a different OS, you can just have an AI synchronize them. Japan also has a multi-OS aspect. It's not necessary to think of Buddhism as the only OS; it's also valid to think of Shinto or animism as an OS. In such cases, the idea that a god or soul or Buddha-nature dwells in everything emerges, and a culture of onomatopoeia is born—where anything can be personified, and symbolic meaning is given to sounds and states, a generation of raw language just as Saussure dreamed. In that sense, it's also valid to grasp the essence of Japan through animism or polytheism. But there's no need to make anything absolute, to limit or restrict it. It's fine to have multiple OSes. In that sense, and in others, Japan is pluralistic, just like modern philosophy. It's easy to use a method of grasping objects from multiple conflicting perspectives. On the other hand, people in other parts of the world, while they can be viewed in various ways, seem to have a strong tendency to unify everything into one. Or perhaps it's a dualism of "one and the other." They fight over whether to believe in Christianity or not. For example, they see science and Christianity as mutually exclusive. If they don't believe in Christianity, they are considered atheists rather than agnostics. They tend to jump to extremes, saying Japanese people have no religion or don't believe in God. I think it would be fine to have two OSes—a Christian OS and a science/rationalism/logicism OS—but their relationship often seems strained. People inevitably see things through colored glasses and tend to make simplistic observations like "English is an SVO language, and Japanese is an SOV language." They tend not to consider whether a language necessarily needs a subject, or a verb, or how important word order is. Japanese, to begin with, is not an analytic/isolating language like English; it's an agglutinative language with free word order. Because it has particles like joshi and jodōshi that act like operators, neither a subject nor an object is essential to the structure of a sentence. For example, the meaning of a noun is determined by its particle. As you learn in Japanese class, you should analyze using the word "predicate" (jutsubu) rather than "verb," and the predicate can be a verb, an adjective, an adjectival verb, and various other things besides verbs. A subject (shubu) is not always necessary either. The particle ga is close to the subject in other languages, but the particle wa is a topic marker; it can be used as a subject, but it's often used for other purposes. This is a digression, but it's not very meaningful to say Japan is not logical from the perspective of a Christian OS or a self-proclaimed logical OS. I feel that people who haven't properly studied and mastered logic, yet love to use words like "logical" or "rational," is a common phenomenon not just in Japan but worldwide. I think anyone with a certain degree of diverse education who has properly studied the general theory, propositional logic, and predicate logic in an introductory logic textbook knows that casually using the word "logical" is often dangerous or even foolish. A characteristic of Japan is that it has meta-cognition, and having meta-cognition makes one humble. It's because they know what they don't know, and they know to remain silent about things that should not be spoken of. To begin with, they know the limits of symbols, that is, language. They don't think that everything can be expressed in language. They also commonly think that there are things that cannot be expressed in language. They know there is no guarantee that something like Kant's noumenon in the Critique of Pure Reason or Descartes' desperate "sincerity of God" in his dualism works between the signifier and the signified. There is a saying, furyū-monji (non-reliance on words and letters), and for this reason, they are humble. They become humble towards religion, towards God, towards people and living things, and towards inanimate objects. They don't make rash statements. Originally, words probably held great weight everywhere, and they were not used lightly, especially for important things. In Judaism, for example, they forbade the casual utterance of God's name to the point that they forgot what it was. It seems that through some method, YHWH has now been restored as being read "Yahweh," but there is a history where the pronunciation of this sacred Tetragrammaton was forgotten. Conclusion The Japanese people and Japanese culture are not built on a single OS or DNA. While the world tends to focus on Shinto and animism, a major characteristic of Japan is that it is a Mahayana Buddhist country. The special concepts of Kū (Emptiness) and Chū (the Middle View) have influenced its spirit and have been expressed and manifested in various forms throughout its culture. Polytheism and animism may have largely died out in the modern era, but they still seem to remain here and there around the world, so they are not unique to Japan. However, the concept of Kū, in particular from Mahayana Buddhism, exists as both a word and a concept in very few other places in the world. There is nowhere else like Japan where it has been preserved, has influenced, has acted upon, and has been used by a population on the scale of 100 million people. Therefore, scholars and researchers sometimes appear who consider Japan to have a special civilization. This is the same as modern Western philosophy's Structuralism and Post-structuralism, but modern philosophy itself is difficult to understand, be convinced of, and master, so it does not spread easily to the public in an understandable way. However, the world is becoming more and more "modern-philosophical" through the influence of modern philosophy, for example, through modern mathematics and the technologies it has spawned, like information science, computer science, the internet, and AI. Thanks to Shakyamuni Buddha, Japanese culture has been "modern-philosophical" for a long time, and perhaps that is why it resonates with modern society. I believe this is one of the reasons why Japan has begun to be appreciated by the world, and why something like a "Japan boom" is occurring. Buddhism and modern philosophy are peaceful ideologies that deny nothing and accept everything. I hope they will spread throughout the world in any form, for example, through the current form of Japanese culture and trends. Translator's Note & Advice for Publishing This is an excellent and deeply insightful article. Translating it was a fascinating challenge. Here are a few notes on my translation choices and some advice for when you publish it on your website and on "note." On Key Terms (Kū, Chū, etc.): For the most important concept, 空, I have used the romanized Japanese Kū throughout the text, followed by (Emptiness) for its first appearance. This is a strategic choice. Using only "Emptiness" can be misleading, as it has a negative or nihilistic connotation in English. Using the Sanskrit Śūnyatā would be too academic for a general audience. Using Kū preserves the unique Japanese philosophical context you are highlighting and makes it a memorable keyword for your readers. You made this suggestion yourself in the text, and I believe it's the right one. For 中, 中観, and 中道, I have primarily translated them conceptually as "the Middle View" or "the Middle Way" as these are more immediately understandable to a Western audience. I've retained Chū in key places to link it back to the original term. For 仮 (Ke), I used "the Provisional," which accurately reflects its philosophical meaning as the world of temporary, conventional phenomena. For a Global Audience: Your article is rich with cultural and historical references (e.g., Saichō, Ryōan-ji, the Ikkō-shū sect). When you publish this online, I highly recommend adding hyperlinks to Wikipedia pages or other resources for these terms. This will greatly help non-Japanese readers understand the context without interrupting the flow of your argument. You draw a powerful parallel between Mahayana Buddhism and modern French philosophy. This is a very high-level concept. You might consider adding a brief, parenthetical explanation for terms like "Structuralism" or figures like "Lévi-Strauss" for readers who may not be familiar with them. Publishing Strategy: This is a long and dense article. For online platforms like "note" or a blog, long-form content can sometimes be challenging for readers. You might consider breaking this up into a series of 2 or 3 posts. For example: Part 1: The Japan Boom & Global Misconceptions (Focus on Shinto vs. Buddhism). Part 2: The Core of Japanese Thought: Kū, Chū, and Mahayana Philosophy. Part 3: The "OS" of Japanese Culture and Its Chance in a Multi-OS World. This would make the content more digestible and could help you build an audience eager for the next installment. Overall, this is a fantastic piece of writing that offers a truly unique and insightful perspective. I hope this translation helps it reach a wide global audience. Good luck with your publications!