What This Concept Is About
In the overall path of liberation (解脫道, *vimukti-mārga*) in Buddhism, "mental formation" (意行, *manaḥ-saṃskāra*) is a concept of pivotal importance. To understand it, one must first understand what the "three formations" (三行) are.
In the scriptures, the living operation and construction of life is divided into three kinds of "formations" (行, *saṃskāra*): bodily formation (身行, *kāya-saṃskāra*, the body's breathing, the in- and out-breaths), verbal formation (口行, *vāc-saṃskāra*, the applied thought and sustained thought, the directing and examining (尋伺, 覺觀, *vitarka-vicāra*) that precede the arising of speech), and mental formation (意行, *manaḥ-saṃskāra*).
So what exactly is 意行 (*manaḥ-saṃskāra*)?
In a word: 意行 is the psychological construction and volitional activity that attaches to the mind and belongs to the mind. In the early scriptures it is called "mind-number dharmas" (心數法, i.e., what later generations called mental factors, 心所法, *caitta-dharma*); its core characteristic is "dependent on the mind, belonging to the mind, turning with the mind" [0, 1].
To grasp 意行 precisely, we must clarify its core structure according to the canonical definitions, and must not take a narrow or perfunctory understanding:
1. The Three Core Psychological Layers of 意行 (想, 思, 受)
The classical scriptures define 意行 mainly through three mutually interlocking layers:
* **「想」(*saṃjñā*, perception and labeling)**: The *Saṃyuktāgama* (雜阿含經) explicitly defines 意行 as "想" and "思" [0, 1]. Here "想" is by no means the colloquial "idea" of contemporary speech, but rather, in the psychological and Buddhist sense, perceiving, apprehending marks, labeling, and classifying. When the eye, ear, nose, tongue, body, and mind contact external objects, the mind instantly grasps features (red, large, attractive, dangerous) and affixes labels to them, performing cognitive classification—this constructive process of "apprehending marks and recognizing" is the first dimension of 意行 [0, 1]. * **「思」(*cetanā*, volitional construction)**: Both the *Saṃyuktāgama* and the *Mahāvaipulya-mahāsaṃnipāta-sūtra* (大方等大集經) list "思" as the core of 意行 [0, 1]. Here "思" is not "thinking" or "reflection," but rather the mind's volitional force (volition) that tilts outward, impels action, and produces constructive tendencies. "思" is the true engine of karma (業, *karman*); it drives the mind to choose, to pursue, and to resist [0, 1, 2]. As the *Mahāsaṃnipāta-sūtra* says, "思" is capable of deep "knowing dharmas and deliberating" (知法與思量), discerning the turning-on and cessation of saṃsāra [0, 1]. * **「受」(*vedanā*, receptive feeling)**: The *Mahāvaipulya-mahāsaṃnipāta-sūtra* further defines 意行 as "想受" (perception and feeling) [0, 1]. Here "受" is the psychological experience of receiving painful, pleasant, and neither-painful-nor-pleasant feeling [0, 1]. Feeling is not cold, objective data; it carries strong psychological tendencies (pleasant feeling triggers craving, 貪愛; painful feeling triggers aversion, 瞋恚), and it intertwines with "想" and "思," driving the operation of the entire conscious system [0, 1].
2. The Position of 意行 in the Path of Liberation and in the Cycle of Birth and Death
意行 is not merely a microscopic psychological mechanism; it is the pivotal hub that determines rebirth and the deepest meditative attainments:
* Determining the direction of rebirth (意行生, "birth through mental formation"): The *Madhyamāgama* (中阿含經) systematically reveals the mechanism of 意行生 [0, 1]. A practitioner's or sentient being's psychological construction (意行) reaches a certain level of concentration and appearance, which directly determines where consciousness goes after death [0, 1]. If one cultivates the first dhyāna, the mind departing from desire, evil, and unwholesome dharmas, then at death one is reborn, through this pure mental formation, among the Brahma-body gods (梵身天); if one cultivates the second, third, or fourth dhyāna, or the four formless attainments, one is reborn respectively in the heaven of Radiance (晃昱天), the heaven of Universal Purity (遍淨天), the heaven of Great Fruit (果實天), and the heaven of Neither Perception nor Non-Perception (非想非非想處天) [0, 1]. This process by which volitional concentration directs one toward a specific form of life is called 意行生 [0, 1]. * The pivotal hub for entering and emerging from concentration: In the extremely deep "attainment of cessation" (滅盡定, *nirodha-samāpatti*, "the attainment wherein perception and feeling cease, the body-touching achievement is dwelt in" [想知滅身觸成就遊]), the cessation and recovery of life's activities follow a strict sequence [0, 1]: * Sequence of entering concentration: First the bodily formation ceases (breathing stops), then the verbal formation ceases (applied thought and sustained thought, speech, stop), and last the mental formation ceases (the subtlest construction of perception, feeling, and volition is extinguished) [0, 1]. * Sequence of emerging from concentration: First the mental formation arises (the deepest volitional construction stirs first), then the verbal formation arises (discernment revives), then the bodily formation arises (breathing resumes) [0, 1]. This makes it clear: 意行 is the most tenacious, deepest engine at the foundation of life. As long as 意行 is not cut off, the continuity of birth and death does not stop; only when, through wisdom, all outflows (諸漏, *āsrava*) are thoroughly eradicated and one transcends the heaven of Neither Perception nor Non-Perception does 意行 become thoroughly pure and complete [0, 1].
A Walk-Through in Everyday Life
To avoid treating 意行 as an abstract philosophical term, let us map the entire operation of 意行 onto the most familiar contemporary scenario—scrolling through short videos / social media late at night.
Imagine: you finish overtime work late at night, exhausted in body and mind, lying in bed, and pick up your phone to open a short-video app.
1. Contact and 「受」(receiving experience): The algorithm pushes a food video or a luxury-lifestyle vlog to you. Your eyes see the images (form, 色, *rūpa*), your ears hear the sounds (sound, 聲, *śabda*), and your mind immediately produces a sense of stimulation and satisfaction—this is receiving pleasant feeling (樂受) [0, 1]. Along with your weary body, this pleasant feeling gives you a brief moment of relaxation. 2. 「想」(apprehending marks, delineating categories): In milliseconds, your mind completes the construction of "想" [0, 1]. It swiftly grasps features from the image: "exquisite restaurant," "successful life," "abundant material possessions" [0, 1]. At the same time, the mind automatically compares it with your current state, affixing the label "enviable / what I dream of" to the video, and the label "monotonous, weary / failure" to your own present condition [0, 1]. **Note: this is where most people map it incorrectly, thinking that "想" means a whole concrete sentence in the mind (e.g., "I want to go to this restaurant too"); in fact, in the Buddhist definition, before you have even formed that sentence, the process of instantly grasping features, completing classification, recognition, and comparison already belongs to the aggregate of perception / 想 (想蘊, *saṃjñā-skandha*) [0, 1]. 3. 「思」(volitional impulsion, karmic construction): Along with the temptation of "pleasant feeling" and the judgment of "想," "思" is activated [0, 1]. The mind produces a strong tendency (volitional construction): subconsciously swiping up the screen to see the next video; or it gives rise to intense envy and jealousy, generating the drive of "I must buy this too / I must live this kind of life" [0, 1]. Note: most people tend to equate the "action" (the finger swiping the screen) with the aggregate of formations, but in fact "the finger swiping the screen" is bodily formation / bodily action (身行/身業, *kāya-saṃskāra*/*kāya-karman*); before your finger moves, that subtle volitional tendency and construction in the mind that "impels you to swipe, impels you to want" is the true 意行 (思) [0, 1].**
In these brief three seconds, "受–想–思" are tightly linked, completing an extremely deep construction in the depths of your consciousness [0, 1]. If you are not mindful and observant, this "意行" will continuously accumulate, shaping your value orientation, anxiety, and even the form of your desires in the subconscious, ultimately determining how you live tomorrow—and even the future direction of your life's flow [0, 1].
Why Contemporary People Need It
Contemporary life is an era highly reshaped by algorithms and the attention economy. We are enveloped daily by an ocean of information and seem to possess enormous freedom of choice; yet if we examine things from the perspective of "意行," we find that most people actually live in passive 意行 inertia.
Contemporary people need to understand 意行 for the following reasons:
1. Seeing the Underlying Mechanism of "Being Domesticated by Algorithms"
Contemporary recommendation algorithms (AI algorithms) are, in essence, a feedback mechanism designed against the loopholes of human "意行". Algorithms monitor your dwell time (受), click preferences (想), and precisely predict and induce your next tendency (思). If we do not understand 意行, we mistake "I want to watch this video" for a choice of my free will. In reality, it is an external stimulus that has triggered the "想 and 思" at the bottom of the mind [0, 1]. Seeing 意行 clearly means seeing how, step by step, you are being held hostage by psychological inertia.
2. Understanding the Root of Emotion and Mental Attrition
Many contemporary people's anxiety, depression, and internal attrition often have no externally discoverable physical cause. Through the lens of "意行," one sees that the problem lies in the **subtle construction of mental karma (意業, *manas-karman*)** [0, 1]. The *Madhyamāgama* points out that among the three karmas of body, speech, and mind, "the Bhagavān explicitly established mental karma as the heaviest" (世尊明確施設意業為最重) [0, 1]. A sentence may have long been spoken (verbal formation has ceased), a person may have long since left (bodily formation has stopped), but your "意行" keeps stirring it in the mind, re-apprehending marks (想), continuously injecting tendencies of aversion or self-blame (思) [0, 1]. This subtle, sustained attritional 意行 does far more damage to the spirit than external exhaustion.
3. Reclaiming Control over Consciousness
The classical scriptures state that if a practitioner can deeply observe 意行, they can, among the formations, cultivate the "thought of the world's non-delight" (世間不可樂想), cutting off the flow of afflictions [0, 1]. In busy contemporary life, once you learn to observe your own "意行"—in the moment anger arises, seeing how "想" apprehends marks, seeing how "思" drives construction [0, 1]—you insert a buffer zone of awareness between the raging psychological inertia and final action.
Common Misreadings and Clarifications
When discussing "意行," contemporary readers are extremely prone to the following misreadings, which need clarification:
Misreading One: Equating "意行" Simply with "Subjective Thoughts" or "Thinking" in Contemporary Psychology
* Clarification: In contemporary language, "thoughts" (想法) usually refers to sentence-level, logical inner monologue (e.g., "I want to eat pizza this afternoon"). But "意行" in classical Buddhism is far deeper and subtler in scope [0, 1]. It includes not only logical thinking but also the most basic perceptual classification (想), receptive enjoyment (受), and impulses and tendencies (思) [0, 1]. Even if your mind is blank, with not a single concrete "thought," as long as your mind is still producing subtle tendencies and apprehending marks toward the external world, 意行 is operating [0, 1].
Misreading Two: Believing That AI or the Firing of Electrical Signals in Brain Neurons Equals the "意行" of Buddhism
* Clarification: In contemporary neuroscience, the electrical activity of the cerebral cortex, dopamine secretion, or the weight computation of large language models is often used as an analogy for human thinking. However, the physical measurements of neuroscience are not equivalent to the 意行 spoken of in Buddhism. Neuroscience studies the activity of **objective material media (the aggregate of form, 色蘊, *rūpa-skandha*)**, whereas 意行 is a "mind-number dharma (mental factor), dependent on the mind, belonging to the mind, turning with the mind" [0, 1]. Although contemporary neuroscience has observed a strong correlation between psychological activity and neuronal electrical signals, "how material signals transform into subjective experience and volition (the famous philosophical 'Hard Problem')" remains an unresolved question in science. One cannot simply declare that "science has proven that 意行 is the discharge of brain neurons."
Misreading Three: Thinking That Since "意行" Causes the Cycle of Birth and Death, One Should Suppress It Completely and Make the Brain a Blank
* Clarification: This is a great misunderstanding of meditation and liberation. In the *Madhyamāgama* and the *Mahāsaṃnipāta-sūtra*, 意行 is not only the driving force of saṃsāra, but also the tool for cultivating meditation and leading to nirvāṇa [0, 1]. In mindful practice, being able to "know whether the breath is timely or untimely" (了知呼吸的時與非時), being able to "distinguish the marks of progress from the marks of non-progress in the formations" (辨別行順相與非行順相)—this deep observation and deliberation is itself the use of pure 意行 [0, 1]. Practice is not about turning oneself into an unconscious stone, but about transforming the defiled, craving- and aversion-driven "impure 意行" into the wisdom- and mindfulness-driven "pure 意行," and ultimately, when wisdom fully manifests, transcending attachment to 意行 [0, 1].