Here is a deep, accessible, and grounded exploration of the Fourth Jhana, written for a contemporary reader.
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### 這個概念在说什么 (What is this concept talking about?)
In the Buddhist path of liberation, 第四禪 (The Fourth Jhana / The Fourth Dhyana) is the absolute pinnacle of the form-realm meditations (色界禪定). If we view the journey of meditation as climbing a great mountain, the earlier stages (the first, second, and third jhanas) are about finding immense joy, bliss, and physical rapture to pull the mind away from worldly desires. But the Fourth Jhana is the summit where even the finest spiritual bliss is left behind. It is the realm of absolute, crystalline stillness.
To understand it, we must look at the strict canonical formula found across the *Agama* sutras (such as the *Dirgha*, *Madhyama*, and *Samyukta Agamas*): 「捨滅苦、樂，先除憂、喜，不苦不樂，護念清淨」 (Abandoning pain and pleasure, with the earlier disappearance of distress and elation, entering a state of neither-painful-nor-pleasant feeling, and the purification of mindfulness by equanimity).
Let’s break down its precise structural layers: 1. The Fading of the Waves (憂喜先斷，捨滅苦樂): We possess mental feelings (distress 憂 and elation 喜) and physical feelings (pain 苦 and pleasure 樂). In the lower jhanas, mental distress and elation have already faded. Upon entering the Fourth Jhana, even the profound physical bliss (樂) of the third jhana is abandoned. 2. The Absolute Neutrality (不苦不樂): What remains is a feeling that is "neither-painful-nor-pleasant." This is not a void; it is a highly refined, perfectly balanced affective state. 3. Mindfulness Purified by Equanimity (捨念清淨 / 護念清淨): Because the mind is no longer being pushed by pain or pulled by pleasure, equanimity (捨, *upekkhā*) reaches perfection. This flawless equanimity acts as a supreme polish for mindfulness (念, *sati*), rendering the mind’s awareness perfectly clear, bright, and immovable.
The Buddha used exceptionally beautiful and precise metaphors to ensure we do not misunderstand this state: * The Metaphor of the White Cloth (白疊覆身喻): In the Fourth Jhana, the feeling of purity pervades the entire body. It is described as a person who, after bathing, wraps themselves completely in a pristine, freshly washed white cotton cloth (白疊). There is no part of the body untouched by this immaculate purity. * The Metaphor of the Lamp in a Closed Room (密室燈火喻): The mind in this state is compared to an oil lamp placed inside a sealed, draftless room. Outside, the winds of the world may howl, but inside, untouched by any external disturbance, the flame remains entirely motionless (怗然不動). It does not flicker, grow, or shrink. * The Metaphor of the Well-Provisioned Border Fortress (邊城物資之喻): The *Madhyama Agama* compares this state to a king's border castle perfectly stocked with abundant resources—ghee, honey, meat, and grain. Because it is so completely self-sufficient internally, it is absolutely secure against any external enemies (symbolizing Mara, the personification of worldly temptation and distraction).
In this state, the mind becomes so deeply still that even the physical breath—the very anchor used to calm the mind earlier on—ceases or becomes so exceedingly subtle that it is described as a "thorn" (入息出息為刺). To notice the breath here would be a disturbance.
### 生活里的走查 (Life Walkthrough)
Let’s map this ancient progression onto a contemporary setting so you can feel the exact weight of these definitions. Imagine you are sitting down on a Friday evening after an incredibly intense, high-stakes week of work.
1. 先除憂、喜 (The earlier disappearance of distress and elation): You turn off your phone. The algorithm is no longer feeding you outrage-inducing news, cutting off mental distress (憂). You also aren't waiting for the dopamine hit of a text from someone you have a crush on, cutting off mental elation (喜). Your mind stops swinging on the pendulum of emotional drama. 2. 捨滅苦、樂 (Abandoning pain and pleasure): As your meditation deepens, the physical backache from hunching over a laptop all week (苦) completely dissolves. More subtly, that warm, cozy, vibrating wave of physical relaxation that usually feels so good (樂) is also gently set aside. You realize that even "feeling really good" is a subtle vibration, a burden that requires energy to maintain. 3. 不苦不樂 (Neither-painful-nor-pleasant): *Common Misconception Alert!* Here, contemporary people often mistakenly map this to "numbing out," "spacing out," or a depressive apathy. But apathy is a dull, heavy state grounded in ignorance. The *不苦不樂* (neutral feeling) of the Fourth Jhana is like perfectly clear, distilled water. It is crisp, utterly awake, and free of the exhausting "flavor" of worldly stimuli. 4. 捨念清淨 (Mindfulness purified by equanimity): Imagine your attention is a 4K camera on a high-end gimbal. Suddenly, a notification screen lights up in the corner of the room, or a loud motorcycle revs outside. In a normal state, your mind would immediately dart toward it, judge it ("So annoying!"), and lose its center. In the Fourth Jhana, the sutras define this as "有法而不覺知" (Having phenomena but not perceiving them in a reactive way). The sound hits your ear, the light hits your eye, but the mind’s flame does not flicker (like the lamp in the closed room). You are fully aware, but the mind does not "grip" the object. 5. 入息出息為刺 (Breathing as a thorn): Normally, you take deep breaths to regulate your nervous system. But in this state of profound stillness, the very movement of your lungs expanding and contracting feels as loud and disruptive as a jackhammer. The physical body goes into such deep rest that the breath suspends, leaving only the pure, radiant knowing.
### 当代人为什么需要它 (Why contemporary people need it)
We live in an era where human attention is the most heavily mined resource on the planet. The entire architecture of the contemporary digital world—algorithms, infinite scrolls, targeted ads—is reverse-engineered to hijack our feelings (*vedana*). They operate entirely on the spectrum of *苦, 樂, 憂, 喜* (pain, pleasure, distress, elation).
The Fourth Jhana represents the ultimate "anti-algorithm" sanctuary. It proves that the human mind has the inherent capacity to generate an internal environment of absolute, unshakable sufficiency (the Border Fortress metaphor).
Contemporary neuroscience often studies states of "flow" or the down-regulation of the brain's Default Mode Network (DMN) during deep meditation, noting profound reductions in self-referential anxiety. While science provides fascinating biological correlates, we must be careful not to equate a brain scan with the existential depth of Buddhist liberation. The Fourth Jhana is not just a bio-hack for stress relief; in the Buddhist path, it is categorized as "增上意學" (Higher Mental Training).
Why do we need this pristine stillness? Because it acts as an operating room. If you want to perform the delicate surgery of uprooting your deepest existential ignorance and fears (such as the fear of death, or the clinging to a permanent self), you cannot do it while your hands are shaking with anxiety or while you are intoxicated by pleasure. The Fourth Jhana provides the "清淨無穢、無煩柔軟、善住不動" (pure, unblemished, pliant, and immovably well-established) mind required to see the Four Noble Truths exactly as they are.
### 常见误读与澄清 (Common Misreadings and Clarifications)
Misreading 1: "Reaching the Fourth Jhana means I am fully enlightened (Nirvana)." *Clarification:* The Buddha strictly warned against this. In the *Dirgha Agama*, mistaking the Fourth Jhana's "neither-painful-nor-pleasant" peace for final Nirvana is classified as a dangerous heresy (the fifth type of "Now-Nirvana" wrong view). The Fourth Jhana is a sharpened tool, not the final goal. If you reach this state and just bask in it without using it to investigate reality (contemplating the five aggregates as a disease or a wound: "思惟五陰如病如癰"), upon death, the karmic momentum of this concentration will simply cause you to be reborn in the high form-realm heavens (such as the Vehapphala / 果實天). While pleasant, this is still within the cycle of Samsara. It is temporary.
Misreading 2: "I must attain the Fourth Jhana to be liberated." *Clarification:* While it is the ideal foundation, the *Samyukta Agama* (specifically the *Susima Sutta*) records instances where monks attained complete liberation from the cycle of birth and death without ever possessing the Fourth Jhana (or any formless attainments). They achieved what is called 慧解脫 (Liberation by Wisdom). They developed just enough concentration to see the impermanence of reality and cut the fetters, proving that wisdom, not just meditative bliss, is the true liberator.
Misreading 3: "Equanimity (捨) means becoming like a rock." *Clarification:* Remember the exact canonical phrasing: 護念清淨 (Mindfulness is protected and purified). If you were a rock, the lamp would be blown out. In the Fourth Jhana, the lamp burns brighter than ever. You are not suppressing the world; you have simply stopped letting the world blow your mind around. It is the profound, radiant stillness of a mind that has finally come home and realized it needs absolutely nothing from the outside to be whole.