身根Body-faculty
色法十一之第五（末根）。五根之第五。為四大種所造之淨色，身識（→#5）之所依，觸境（→#69）之能取。不可見、有對。⭐ 身根遍布全身——與其他四根（眼耳鼻舌）局限於頭部不同——是五根中所緣境最廣者。
漢zh · Xuanzang 譯
色法十一之第五（末根）。五根之第五。為四大種所造之淨色，身識（→#5）之所依，觸境（→#69）之能取。不可見、有對。⭐ 身根遍布全身——與其他四根（眼耳鼻舌）局限於頭部不同——是五根中所緣境最廣者。
經
[共傳] 《雜阿含經》卷十三（經322，T2n0099_p0091c05–06）：
眼是內入處，四大所造淨色，不可見，有對。耳、鼻、舌、身內入處亦如是說。
⭐ SA 322「亦如是說」之攝至此涵全五根。
[大乘] 《大佛頂首楞嚴經》卷五（畢陵伽婆蹉身根圓通章），二十五圓通之第十：
畢陵伽婆蹉，即從座起，頂禮佛足，而白佛言：我初發心從佛入道，數聞如來說諸世間不可樂事。乞食城中，心思法門，不覺路中毒刺傷足，舉身疼痛。我念有知，知此深痛；雖覺覺痛，覺清淨心，無痛痛覺。我又思惟：如是一身，寧有雙覺？攝念未久，身心忽空。三七日中，諸漏虛盡，成阿羅漢，得親印記，發明無學。佛問圓通，如我所證，純覺遺身，斯為第一。
——⭐⭐ 畢陵伽婆蹉之身根圓通呈現一個現象學上獨特之觀照工夫：「雖覺覺痛，覺清淨心，無痛痛覺」——觀察「痛之覺」與「清淨心之覺」二者之間隙（「一身寧有雙覺」），由此間隙而入「身心忽空、純覺遺身」。此乃五根圓通中現象學上最精細之入路：不於身外、不於身轉，而於身與覺之介面處消融二元。
論
《大乘五蘊論》（玄奘譯，T31n1612_p0848b15）：
云何身根？謂所觸為境清淨色。
⚠ In Review · 《大乘五蘊論》 此處作「所觸為境」（非平行之 prefix），保留一分（ekadeśa）之限定——身根之所緣為「所觸」之分位，非觸塵之全體（四大種本身為觸塵之初級部分，非所造；故 《大乘五蘊論》 之 prefix 結構於身根原文上獨見）。
按：身根於 baifa 之三獨特處——(1) 遍布全身（其他四根局限於頭部）；(2) 觸境最廣（《雜集論》列二十二觸：滑澁輕重軟緩急冷飢渴飽力劣悶癢黏病老死疲息勇）；(3) 《大乘五蘊論》 之「所觸」prefix 保留一分之精細結構，乃身根之文本獨特標記。
梵saṃskṛta
kāya-indriya < kāya（身、所積聚者）+ indriya（根；詳 #60）。
kāya < √ci「聚、集、積累」+ -aya（抽象/結果後綴）。⚠️ 印歐祖語同源不確：可能與印歐祖語 *kʷei- 「堆積」有關，但 Indo-Iranian 之外無穩固對應。en 段不主張 IE 同源鏈；honest 位置為「印歐祖語不確、限於 Indo-Iranian」。
⭐⭐⭐ kāya 之語源即教義——Skt kāya 字面義為「所積聚者」、「堆」；身為四大種之 aggregation 而非 substantial 個體，乃此語源之直接 implication。漢「身」字本義亦含「人形之集合」（甲骨文象人形腹大者，孕之原字）。kāya 與 skandha（蘊、堆）共「集合」之義理義——兩詞於佛法破實體論派解剖中作為「身體不是實體而是聚合」之 lexical 雙重錨。Pāli kāya 直承同形（無音變）。
⚠ In Review · Pāli kāya 之 lexical 廣度（同 Skt）：可指（1）身根（abhidharmic 官能，本條義）、（2）身全體（全身，色身廣義）、（3）泛指「集合、群」（如 dhamma-kāya、saṅgha-kāya）。⭐ 此三義之系統地 ambiguity 正 reflect 「身=堆=集合」之語源核心——三義共 ci-/√聚 之動詞語義基底。
《阿毘達磨集論》（Abhidharma-samuccaya，Pradhan 校本 [Abhidh-s 3]）：
kāyendriyaṃ katamat / catvāri mahābhūtānyupādāya kāyavijñānāśrayo rūpaprasādaḥ //
何為身根？依四大種，為身識之所依，淨色。
按：Asg 公式同 #60；《大乘五蘊論》「謂所觸為境清淨色」之「所觸」prefix 為 5 根中之獨例，preserves ekadeśa 之精細結構。
巴pāḷi
南傳 28 色法之 kāya-pasāda，5 種 pasāda-rūpa 之第五（末位）。
| 瑜伽行派 | 南傳 | 對應度 |
|---|---|---|
| kāya-indriya | kāya-pasāda | ✅ 直接對應 |
Skt → Pāli：kāya → kāya（identity；無音變）。
經
Kāyañca paṭicca phoṭṭhabbe ca uppajjati kāya-viññāṇaṃ. 緣身與觸，生身識。
⭐ 身根之經層 practice 錨尤深：四念處（cattāro satipaṭṭhānā）之第一即身念處（kāyānupassanā），《長部》DN 22 Mahāsatipaṭṭhāna-sutta、《中部》MN 10 Satipaṭṭhāna-sutta：
Kāye kāyānupassī viharati ātāpī sampajāno satimā vineyya loke abhijjhā-domanassaṃ. 於身觀身而住，熱誠、正知、具念，調伏世間貪憂。
——身念處之 kāya 為 kāya 廣義（全身、色身）而非 kāya-indriya 狹義（身根）；但身根作為觸覺之功能性錨，是身念處所依之物理基底。
論
⚠ In Review · Vism XIV.51 kāya-pasāda 四相，結構同 #60，逐字 Pāli 待字元核校：
| 四相 | Pāli | 義 |
|---|---|---|
| lakkhaṇa | phoṭṭhabb'âbhighātârahaṃ bhūtappasādaṃ ⚠️ | 堪受觸境之大種淨色 |
| rasa | phoṭṭhabbesu āviñchanaṃ ⚠️ | 於諸觸中令意趣向 |
| paccupaṭṭhāna | viññāṇassa ādhārabhāvo ⚠️ | 為身識之所依 |
| padaṭṭhāna | phusitukāmatā-nidāna-bhūta-sambhūta ⚠️ | 由「欲觸」之業所成大種 |
按：身根之南北彙合結構同典範。⭐ 身根之跨傳承 practice 彙合與 #62 同強——身念處（kāyānupassanā）為南北傳共傳之根本禪修（四念處之首），其物理基底即此身根。Asg / 瑜伽行派之 abhidharmic 定義 + Vism / 南傳之 satipaṭṭhāna 框架 + 楞嚴 [大乘] 之圓通入路——三系統共指同一官能，三系統共認此官能為 contemplative entry-point 之立基-zero。
漢綜述zh-synthesis
「身根」之梵文 kāya-indriya 為兩段合成——kāya（身、所積聚者）+ indriya（根，詳 #60 詞源段）。kāya < √ci「聚、集、積累」+ -aya（抽象/結果後綴），字義「所積聚者」「堆」。⚠️ 印歐祖語同源不確：可能與印歐祖語 *kʷei-「堆積」有關，但 Indo-Iranian 之外無穩固對應；印歐祖語鏈不確（同眼根、鼻根），honest 位置為「IE 不確、限於印度伊朗語族內部」。en 段不主張 IE 同源鏈。Pāli kāya 直承同形（identity，無音變）。⭐⭐⭐ 此條之語源即教義——Skt kāya 字面義「所積聚者」「堆」，已蘊含佛法非實體論身體觀之核心主張：身為四大種之 aggregation 而非 substantial 個體。Skt 內部同根：citi（積、火堆）、caya（積、堆）、saṃcaya（積累）。⭐⭐ kāya 與 skandha（蘊）之語義雙重錨：skandha（蘊）本義亦為「堆、積」——兩詞共指「聚集而非實體」之佛法身體觀，於梵文內部形成語義雙重錨定。漢字「身」字甲骨文象孕婦腹大形（積聚之意象），亦獨立達「聚積」而非「實體」之義。⚠️ 身根 vs 心法之「身」之術語分判：kāya 於梵巴文中兼指（1）身根（abhidharmic 官能，本條義）、（2）色身全體（廣義身體）、（3）泛指「集合、群」（dharma-kāya、saṅgha-kāya 等）；漢傳之「意生身」（manomayakāya）等複合詞中之「身」為廣義 kāya（色身集合義），非 kāya-indriya 之官能義——此術語 ambiguity 於閱讀唯識心所與色法條目時需辨。prasāda（淨）之印歐祖語 *sed- 詞源鏈為五根共用語源骨幹（詳 #60 詞源段）；kāya-pasāda 之 pasāda 同此詞根。
身根為色法十一之第五（末根）、五根之第五。義理核心同 #60 典範三軸：四大種所造之淨色（catvāri mahābhūtānyupādāya rūpaprasādaḥ）+ 身識（→#5）之所依（vijñānāśraya）+ 觸境（→#69）之能取。Asg 公式「kāyendriyaṃ katamat / catvāri mahābhūtānyupādāya kāyavijñānāśrayo rūpaprasādaḥ」為 #60 公式之單字代換（cakṣur- → kāya-）。⭐ 《大乘五蘊論》之文本獨特標記：《大乘五蘊論》「云何身根？謂所觸為境清淨色」——五根《大乘五蘊論》漢譯中唯身根以「所觸」（而非平行之「觸」）為境之 prefix，保留梵文 spraṣṭavya-ekadeśa（觸之一分）之限定精義：觸境之全體中，四大種本身為初級 bhūta-rūpa（大種色），身根之所緣唯取 upādāya-rūpa（所造色）之分位，非觸塵全體；《大乘五蘊論》此 prefix 為五根之文本獨例。「不可見、有對」之義理分判詳 #60 典範義理段。⭐⭐ 身根之三個架構獨特處：(1) 遍布全身——kāya 之物理分布覆全身（對比眼/耳/鼻/舌 4 根之 localized 部位）；(2) 觸境域具二十二子目——《瑜伽師地論》等列二十二觸（滑澁輕重軟緩急冷飢渴飽力劣悶癢黏病老死疲息勇），Asg 觸境（→#69）展開最為豐富；(3) 《大乘五蘊論》「所觸」prefix——五根中之文本獨例，見上。色法架構（阿賴耶異熟變現、無 āśraya-parāvṛtti）詳 #60 義理段。本條為五根之第五（五根末位）。
身根之南北傳對應同 #60–#63 典範之完全收斂模型：南傳 kāya-pasāda（身淨色）與瑜伽行派 kāya-indriya 對應——名同、義同（淨色 + 識所依）、位置同（5 pasāda-rūpa 之末 / 5 indriya 之末）。Skt → Pāli：kāya → kāya（identity，無音變）——五根唯一之 identity pair。Vism XIV 之 kāya-pasāda 四相結構與 Asg 雙義收斂。⭐ 南傳 Vism 尚有一入身根之獨特比喻：kāya-pasāda 遍布全身「如油入棉」（結構性指引；精確 Pāli 俟字元級核校）——此喻直觀呈現身根之非點狀分布，補足 Asg 公式之未明。⭐ 身根之跨傳承修持彙合廣且深——身念處（kāyānupassanā，觀身四念處之首，DN 22 Mahāsatipaṭṭhāna、MN 10 Satipaṭṭhāna）以身根為修觀之立基處；南傳 vipassanā、藏傳身觀修持、漢傳楞嚴之身根圓通（畢陵伽婆蹉「純覺遺身」，→#64 §漢段已引）三系統共指此一根為修觀之立基。注意：四念處之kāya（「於身觀身而住」之kāya）為色身廣義，非單指 kāya-indriya 官能義；身根作為觸覺之功能性錨，是身念處所依之物理基底。
身根之修持涵涉廣闊——涉身念處 / 食前五觀 / 安般 / 不淨觀 / 觀身受等多重修持架構。觸覺之修持特性：身根所緣之觸（spraṭṭavya）是禪定中持久在場的感官現象——坐姿之重量、呼吸之身體感、疼痛之現起——皆由身根所知。身根於修觀中之獨特貢獻（畢陵伽婆蹉之楞嚴段所精細呈現）：身根同時以兩個模式向修行人開放——（1）身作為被感之物（感覺、疼痛、樂受、中性）；（2）身作為從其感之處（能知感覺之覺，有別於感覺本身）。觀察兩個模式之間隙（「一身寧有雙覺」），即 vipassanā 於漢傳之精細呈現：「雖覺覺痛，覺清淨心，無痛痛覺」（→#64 §漢段已引原文）。「純覺遺身」（身心忽空、純覺遺身）是此間隙被持續觀照後之開放——「遺身」者非修行人拋棄身體，乃身根之「被感之物」面向不再遮蔽「能知之覺」。身念處之普遍性：安那般那念（鼻根，→#62）在深修中亦回落為身體感（呼吸在胸腹之觸）——修觀諸多法門最終皆回到身根之觸覺層面，是身根作為修觀之共同回歸處之意涵。⚠️ 楞嚴經之引用依據詳 #60 譯者按 [大乘] 引文選用說明。
漢譯「身根」為玄奘之既譯——「身」為 kāya 之意譯（取「身體」義），「根」字取「根本所依」義（詳 #60 譯名段）。英譯 Body-faculty（平行譯，本譯沿用），輔以「distributed across the entire body rather than localized」之釋義性補充——明示身根之遍布全身特性（vs 其他四根之頭部局限）。Kāya < √ci「聚」之語源核心英文呼應：英文 body < 古英 bodig（語源不明）與拉丁 corpus < 印歐祖語 *kʷrep-「形、體」皆非 kāya 之同源詞——梵文之命名選擇（kāya = 「積聚」）正是佛法非實體論之語言學 embodiment，而西方語言以「形/體」命名身體之選擇則隱含不同之本體論預設；此差異本身即一義理觀察，非翻譯問題。「所觸為境」之英文處理：《大乘五蘊論》之「所觸」prefix 對應 spraṭṭavya-ekadeśa（a portion of the touchable），英譯用「the touchable domain, specifically its derived-matter portion」之釋義策略，以免 touch 一詞之籠統掩蓋原文之精細結構。
身根 ——依四大種，為身識（→#5）之所依，觸（→#69）之能取；淨色為性，不可見、有對。
英綜述en-synthesis
Sanskrit kāya-indriya compounds kāya ("body, aggregate") and indriya ("faculty," see #60). Kāya derives from √ci ("to gather, accumulate, pile up") with abstract suffix -aya, literally "what is gathered" or "the heap." The IE attestation is uncertain: a possible PIE *kʷei- ("pile up") root has only Indo-Iranian internal evidence; no securely-established cognate set exists in Latin, Greek, or Germanic. Pāli kāya preserves the form unchanged. The doctrinal payload of this etymology is more important than the IE chain: the body, in Sanskrit, is named for what it is in Buddhist anti-substantialist analysis — an aggregation, a heap, not a substance. The same root and the same semantic field generate skandha ("heap, aggregate" — the five khandhas are literally "the five heaps"); saṃcaya ("accumulation"); kāya in extended senses (dharma-kāya "the body of doctrine" as accumulation of teachings; saṅgha-kāya "the body of community" as accumulation of practitioners). The Chinese character 身 in its archaic form depicts a person with a swollen abdomen (originally meaning "pregnant," extended to "body") — an image of accumulation rather than substance. Where Indo-European languages typically name the body with a substance-suggesting term (English body < Old English bodig, etymologically obscure but semantically substance-like; Latin corpus < PIE *kʷrep- "form, body"), Sanskrit's kāya encodes the dharmic claim directly into the word: "body" means "what is gathered." (False-cognate alert): English body and Latin corpus are not etymologically related to Sanskrit kāya; the doctrinal-semantic resonance does not rest on cognate-status but on the language's own semantic choice.
The body-faculty in Yogācāra is the fifth and final of the five indriyas, structurally identical to the preceding four in all architectural respects — clarified material substrate (rūpa-prasāda) derived from the four primary elements, serving as internal support (āśraya) for body-consciousness (→#5) to arise with respect to the touchable (→#69). The Asg formula gives kāya-indriya with single substitution from the eye-faculty template; the five-channel parallelism and ālaya-projection points apply unchanged. Three features make the body-faculty distinctive within the five: (1) Spatial extension — unlike the eye, ear, nose, tongue (all localized in the head region), the body-faculty is distributed throughout the entire physical body; touch-receptivity is not point-localized but extended across the whole skin-surface and into the body's interior. (2) Object-domain breadth — the touchable (spraṣṭavya) is the most enumerated of the five sense-objects. The Yogācāra Abhidharma-samuccaya-vyākhyā lists twenty-two touch-types: smooth, rough, light, heavy, soft, slow, swift, cold, hunger, thirst, satiation, force, weakness, faint, itch, sticky, sick, old, dying, weary, rest, vigorous. (3) The "ekadeśa" qualifier in 《大乘五蘊論》 — among the five Yogācāra Chinese-canonical definitions, only the body-faculty's renders as 「所觸為境」 (rather than the parallel-form 「觸為境」), preserving the Sanskrit spraṣṭavyānām ekadeśaḥ ("a portion of the touchable") qualification: not all of the touch-domain is upādāya-rūpa (derived matter); the four primary elements themselves are bhūta-rūpa (primary matter), and the body-faculty grasps only the upādāya portion of the touch-domain. This minor 《大乘五蘊論》 variation is doctrinally significant.
Theravāda's kāya-pasāda maps one-to-one onto Yogācāra's kāya-indriya at every architectural joint: same structural position (fifth of five pasāda-rūpas / indriyas), same definition (clarified matter, four great elements, support for body-consciousness, the touchable as object), same morphological qualifier, same Skt → Pāli phonological identity (kāya → kāya, no sound change). Vism's four-fold for kāya-pasāda structurally converges with Asg's compact definition. The body-faculty is also the deepest cross-traditional practice convergence point in the five-indriya cluster: kāyānupassanā ("contemplation of the body") is the first of the four foundations of mindfulness (satipaṭṭhāna) in canonical Theravāda (Mahāsatipaṭṭhāna-sutta DN 22, Satipaṭṭhāna-sutta MN 10) and is preserved as a primary contemplative discipline across all Buddhist schools — Tibetan lus tsa lung practices, East Asian Chan body-scan, Theravāda vipassanā body-noting. The Mahāyāna Śūraṅgama-sūtra's body-faculty yuán-tōng (Pilindavatsa's "pure-awareness leaving the body") works at the same physical substrate as the satipaṭṭhāna body-contemplation. Three independent doctrinal frameworks — abhidharmic faculty-definition, satipaṭṭhāna foundational practice, yuán-tōng Mahāyāna entry-point — all anchor at the body-faculty.
The body-faculty is the contemplative anchor that almost all practical Buddhist meditation systems return to. Body-scanning, breath-following (which in deep practice is felt as a body-sensation), posture awareness, the felt sense of weight and contact at the cushion — the body-faculty is what makes any of this possible. The body-faculty's distinctive contribution to contemplation — and what the Pilindavatsa yuán-tōng surfaces with unusual phenomenological precision — is that the body presents two modes simultaneously to a sufficiently attentive practitioner: (1) the body as felt object (sensation, pain, pleasure, neutrality — what the body-consciousness immediately knows), and (2) the body as felt-from (the awareness that knows the body, distinct from the sensation itself). Pilindavatsa's poison-thorn injury becomes the meditative lens precisely because the pain is too acute to ignore: "I had the awareness of the deep pain; while there was awareness aware of pain, the pure-mind awareness had no painful pain-awareness" (雖覺覺痛，覺清淨心，無痛痛覺). The contemplative move is to notice the gap between these two — "does one body have two awarenesses?" (一身寧有雙覺). When the gap is held, body and mind both empty (身心忽空), and what remains is pure awareness leaving the body (純覺遺身). This is vipassanā in its Mahāyāna register: the same contemplative seam that the Theravāda kāyānupassanā tradition develops through systematic noting, the Śūraṅgama develops through the phenomenology of acute body-sensation. The body-faculty's deepest practitioner-relevance is that it is always-already on (sensation does not cease while the body lives), always close-at-hand (no apparatus or scripture needed), and structurally suited to the central Buddhist contemplative move of disentangling the knowing from the known. ⚠️ Provenance: Śūraṅgama disclaimer per v1 introduction.
Body-faculty (kāya-indriya) — the clarified material substrate, derived from the four primary elements, that serves as the internal support of body-consciousness with the touchable domain as its object; non-visible, occupying physical space, distributed across the entire body rather than localized; regenerated continuously by the maturation-projection of the storehouse-consciousness; fifth and final of the five sense-faculties; named by a Sanskrit root meaning "what is gathered, the heap" — the body as aggregation rather than substance.
譯translator's note
譯者按： 五根範式之結構分析詳 S3 色法論文（⚠️ 論文編號待確認）。值得標記之 #64 獨特觀察為 kāya 之語源即教義——kāya < √ci「聚」之語源本身已蘊含佛法非實體論身體解剖之核心主張：身為四大種之積聚而非實體；同根 skandha（蘊）之「堆」義（→各蘊條目）構成梵文內部之語義雙重錨定，與 kāya 共指「聚集而非實體」之佛法身體觀；漢「身」字甲骨文象孕婦腹大形（聚集之意）亦獨立達同義。身根作為五根之終，亦是四念處之首（身念處）、楞嚴圓通之現象學上最精細入路（畢陵伽婆蹉「純覺遺身」）——三系統共指此一根。（[大乘] 楞嚴圓通引文之來源框架詳 #60 譯者按 §[大乘] 引文選用說明。）