慧Discerning Wisdom
別境五之第五。簡擇為性，斷疑為業。
漢zh · Xuanzang 譯
別境五之第五。簡擇為性，斷疑為業。
經
[共傳] 《雜阿含經》卷二十六（647 經，T2n0099），五根相應之慧根定義：
何等為慧根？若比丘苦聖諦如實知，苦集聖諦如實知，苦滅聖諦如實知，苦滅道跡聖諦如實知，是名慧根。
亦見同卷 SA 646 之 schematic 句:「慧根者，當知是四聖諦。」漢譯展開句對應 Pāli SN 48.10 之 udayatthagāminī paññā ... ariyāya nibbedhikāya sammā dukkhakkhaya-gāminiyā。
[大乘] 《解深密經》卷三·分別瑜伽品（玄奘譯，T16n0676，T16.0698a11-14）—— 毘鉢舍那（vipaśyanā）之經典大乘定義：
即於如是三摩地影像所知義中，能正思擇、最極思擇，周遍尋思、周遍伺察，若忍、若樂、若慧、若見、若觀，是名毘鉢舍那。
論
《成唯識論》卷五：
慧謂於所觀境，簡擇為性，斷疑為業。謂觀德、失、俱非境中，由慧推求，得決定故。
按：三層引文呈慧義之義理縱深——阿含 SA 647 立慧根為四諦如實知（修道之本體終點）；解深密經以毘鉢舍那（「能正思擇、最極思擇」）定慧為止觀架構之主動觀察一翼，五項展開（忍／樂／慧／見／觀）之中央即慧；唯識論則於心所層面拆慧為「簡擇⋯由慧推求得決定」，將慧之 outcome 連於勝解（→#15，印持）—— 別境五循環復起。三層皆指：慧為認知之主動觀察，其終於決定，成下一念之基。共傳定慧 = 四諦智，大乘標慧 = 毘鉢舍那之核心，唯識論立慧 = 心所（cetasika）階之 simple-and-decide 操作。
梵saṃskṛta
pra-（「前、向前」）+ √jñā（PIE *ǵneh₃- 「知」）—— 直譯「前知／向前之知」=「洞察、揀擇」。√jñā 同根諸瑜伽行派心識詞——同一印歐祖語根，加不同前綴，切分認知功能：
| 詞 | 構造 | 功能 |
|---|---|---|
| saṃ-jñā（想，→#12） | "together-know" | 取像、施設名言 |
| pra-jñā（慧，本條 #18） | "forth-know" | 揀擇、斷疑 |
| vi-jñāna（八識，→#1-#8） | "apart-know" | 了別 |
| ā-jñā | "toward-know" | 教法、命令 |
| a-jñāna | "non-know" | 無明 |
拉丁同源：(co-)gnōscō（< 印歐祖語 *ǵn̥h₃-sḱéti）；希臘同源：gignṓskō, gnōsis（直接借入英文成 gnosis）；英文同源：know (< OE cnāwan)、cognition, recognize, prognosis。注意：英文 wisdom 之詞源實為印歐祖語 *weyd-（同 vedanā 之 √vid 根），非 *ǵneh₃- 系——故「wisdom」譯 prajñā 屬語用慣譯，非語源精譯；精譯應為「(pro-)cognition / fore-knowing」。希臘語借入之 gnosis 為 prajñā 於英語中最近之語源鏡像。
《阿毘達磨集論》（Abhidharma-samuccaya，Pradhan 校本）：
prajñā katamā / upaparīkṣya eva vastuni dharmāṇāṃ pravicayaḥ / saṃśaya-vyāvartana-karmikā //
何為慧？於所觀察境（upaparīkṣya eva vastuni —— 同 samādhi 之所觀境），諸法之揀擇（dharmāṇāṃ pravicaya）為性。斷疑（saṃśaya-vyāvartana）為業。
| 梵文 | 玄奘譯 | 義 |
|---|---|---|
| upaparīkṣya eva vastuni | 於所觀境 | 於同（eva）所觀察之境 |
| dharmāṇāṃ pravicaya | 簡擇 | 諸法之揀擇 |
| saṃśaya-vyāvartana-karmikā | 斷疑為業 | 以遣斷（vyāvartana）疑（saṃśaya）為業 |
按：成唯識論卷五「於所觀境，簡擇為性，斷疑為業」即此梵文之逐字對應—— pravicaya = 簡擇；saṃśaya-vyāvartana* = 斷疑。「upaparīkṣya eva vastuni」之 eva 教義 載重：Asg 用「eva」（即、正同）標示——慧之所緣正是定（→#17）之所緣，非另一境。此即止觀雙運之梵文文本之根：定持之、慧揀之、同一境也。功能子句之轉折亦堪注意：自信→欲→精進→念→定之每一 X-sanniśrayadāna（為下一心所之所依）模式，至 prajñā 變為 saṃśaya-vyāvartana（直接除障）—— 鏈於慧終結並轉外，不再為「下一心所」鋪墊，而直行除疑。*
巴pāḷi
別境心所（pakiṇṇaka cetasika）。三十七道品中以慧為核心之諸法：五根之慧根（paññindriya）、五力之慧力（paññābala）、七覺支之擇法覺支（dhammavicaya-sambojjhaṅga）、八正道之正見（sammā-diṭṭhi）—— 慧於南傳修道架構之諸層皆居要位。
經
《相應部·根相應》 SN 48.10 Dutiyavibhaṅgasutta（與信條 #19 同經，亦定義五根之慧根；CSCD）：
Paññindriyaṃ kho, bhikkhave, idha ariyasāvako paññavā hoti udayatthagāminiyā paññāya samannāgato ariyāya nibbedhikāya sammā dukkhakkhaya-gāminiyā.
比丘！何為慧根？聖弟子有慧——具生滅慧（udayatthagāminī paññā，觀生滅之慧），聖、決擇（nibbedhika）、正趣苦盡。
亦可參《中部》 MN 43 Mahāvedalla——舍利弗於慧定義之問答：
"Pajānāti pajānātī"ti kho, āvuso, tasmā 'paññavā'ti vuccati. Kiñca pajānāti? "Idaṃ dukkha"nti pajānāti, ... "ayaṃ dukkha-nirodha-gāminī paṭipadā"ti pajānāti.
「了知、了知」故，名為有慧者。何所了知？了知苦、苦集、苦滅、趣苦滅道。
按：信條 #19 與本條 #18 共同 SN 48.10 之證攝——五根架構於南傳同一經中完整界定，於信 / 慧兩端揭其首尾呼應；慧根為五根之終，亦為解脫之中道智之所依。
論
《清淨道論》 XIV.7（行蘊·章首慧之四相，paññā 章之 framing 概念）：
| 四相 | Pāli | 義 |
|---|---|---|
| 相 lakkhaṇa | dhamma-sabhāva-paṭivedha | 通達諸法之自性 |
| 業 rasa | moha-andhakāra-viddhaṃsana | 破除覆蔽諸法自性之癡闇 |
| 現 paccupaṭṭhāna | asammoha | 不癡 |
| 足處 padaṭṭhāna | samādhi（引 AN V.3「samāhito yathābhūtaṃ pajānāti」） | 定 |
按：Vism paṭivedha（通達）與 Asg pravicaya（揀擇）兩語名同一認知操作；Vism moha（癡）較 Asg saṃśaya（疑）為廣（疑為癡之一分位）。Vism 以 samādhi 為 paññā 之足處，正是 Asg 中 samādhi 功能子句 jñāna-sanniśrayadāna 之鏡像——Asg 從定言「為慧依」，Vism 從慧言「定為我足」；同一架構，雙向陳述。Pāli 有 paññā / ñāṇa 之雙詞對：paññā 為心所（cetasika）之慧根，ñāṇa* 為慧操作於具體所緣所生之認知事件—— 梵文 prajñā / jñāna 同此別。南北傳於慧—定架構 relation 完全一致。*
漢綜述zh-synthesis
「慧」之梵文 prajñā 為 pra-（「前、向前」）+ √jñā（印歐祖語 *ǵneh₃- 「知」）——直譯「前知／向前之知」即「洞察、揀擇」。印歐祖語 *ǵneh₃- 為印歐語系保存廣泛之認知根（拉丁、希臘、日耳曼、印度-伊朗四大支皆有完整繼承）：拉丁同源 (co-)gnōscō（< *ǵn̥h₃-sḱéti）→ cognitio；希臘同源 gignṓskō / gnōsis（後者直接借入英文成 gnosis）；英文同源 know（< 古英 cnāwan）、cognition、recognize、prognosis。√jñā 於唯識心所學中以前綴切分諸認知功能：saṃ-jñā（想，→#12，共知）、pra-jñā（慧，本條，前知）、vi-jñāna（八識，→#1–#8，了別）。值得記錄之精讀校正：英文 wisdom 之詞源為印歐祖語 *weyd-（同 vedanā 之 √vid 根），非 *ǵneh₃- 系——故「wisdom」譯 prajñā 屬語用慣譯，非語源精譯；精確語源鏡像當為「gnosis」或「pro-cognition」。
《阿毘達磨集論》定義慧（別境五之第五）：「prajñā katamā / upaparīkṣya eva vastuni dharmāṇāṃ pravicayaḥ / saṃśaya-vyāvartana-karmikā //」——「於所觀察境（upaparīkṣya eva vastuni，「正同」定（→#17）之所觀境），諸法之揀擇（dharmāṇāṃ pravicaya）為性；斷疑（saṃśaya-vyāvartana）為業。」《成唯識論》卷五「於所觀境，簡擇為性，斷疑為業。由慧推求，得決定故」乃此梵文之逐字對應——pravicaya = 簡擇；saṃśaya-vyāvartana = 斷疑。Asg 之「eva」（即、正同）載重義理：慧之所緣正是定所已安立之所緣，非另一境——此為止觀雙運（śamatha-vipaśyanā-yuganaddha）之梵文文本根：定（止）持境，慧（觀）揀境，同一境也。此功能子句之轉折詳 #17 paradigm 義理段。
《雜阿含》卷二十六 SA 647（五根相應展開句）：「何等為慧根？若比丘苦聖諦如實知……是名慧根。」亦見 SA 646 之簡句：「慧根者，當知是四聖諦。」Pāli《相應部》SN 48.10（Dutiyavibhaṅgasutta）之慧根（paññindriya）定義：「聖弟子有慧——具生滅慧（udayatthagāminī paññā），聖、決擇、正趣苦盡。」慧於三十七道品中有四重：慧根（paññindriya）、慧力（paññābala）、擇法覺支（dhammavicaya-sambojjhaṅga）、正見（sammā-diṭṭhi）。《清淨道論》XIV.7 以四相析慧（置於章首，作全章之貫穿概念）：相 dhamma-sabhāva-paṭivedha（通達諸法之自性）、業 mohandhakāra-viddhaṃsana（破除覆蔽諸法自性之癡闇）、現 asammoha（不癡）、足處 samādhi（引 AN V.3「samāhito yathābhūtaṃ pajānāti」）。Vism 以 samādhi 為慧之足處——Asg 從定之功能子句言「為智之所依」（jñāna-sanniśrayadāna，→#17），Vism 從慧之足處言「定為我基」——同一架構，雙向陳述；南北傳於定→慧之修習序列完全一致。Vism paṭivedha（通達）與 Asg pravicaya（揀擇）名同一認知操作；Vism moha（癡）較 Asg saṃśaya（疑）為廣——疑為癡之一種顯現，巴利傳統就廣義立目，Asg 就狹義立目。
慧通三性——如實揀擇之慧趨向解脫；被煩惱牽引之慧（詳 §譯者按）則為輪迴頑固之支撐（成 satkāya-dṛṣṭi 等帶 prajñā 之我執架構）。修持上之核心：慧必以定（→#17）為所依，定必以念（→#16）為基礎，念持所學之境——別境五之修習鏈在此以慧之「斷疑」終結並轉外。《成唯識論》卷五附加「由慧推求，得決定故」——慧之推求所得之「決定」，恰是下一輪勝解（→#15）之所依；別境五因此非嚴格之一次性線序，而是以慧之「得決定」回饋於勝解之一個認知循環。修持之警醒：慧與定缺一不可——定無慧為枯定（單純止息而無觀察）；慧無定則無安立之地；同一修行事件之止觀雙運，已在 Asg 之「upaparīkṣya eva vastuni」（正同所觀境）一詞中內建。
玄奘以「慧」取 prajñā，漢字含「洞徹明察」之義，合 pravicaya（揀擇）之核心。英譯 Wisdom（通行）為語用慣例，語源上對應 vidyā 而非 prajñā（見詞源段）；精確之英文語源等位詞為「gnosis」，或合成之「discerning wisdom」（區辨性的智）。 Discernment 直取 pravicaya 之操作義，保留「揀擇」的主動感。⭐ 慧居定（→#17）之後，為別境五修習鏈之終端；功能 saṃśaya-vyāvartana 終結鏈內「為 X 之所依」之傳遞模式，直行斷疑而轉外。
慧 ——於所觀境，簡擇為性；斷疑為業。
英綜述en-synthesis
Sanskrit prajñā compounds pra- ("forth, forward") with √jñā ("to know"), reflecting PIE *ǵneh₃- "to know" — the same root that yields Latin (co-)gnōscō, Greek gignṓskō / gnōsis, and English know, knowledge, cognition, recognize, prognosis. Within Yogācāra, the root √jñā yields a family of cognitive terms divided by prefix: saṃ-jñā (#12, together-knowing → recognition), vi-jñāna (apart-knowing → consciousness, the eight 心王 #1-#8), ā-jñā (toward-knowing → command, instruction), a-jñāna (non-knowing → ignorance), and here pra-jñā — fore-knowing, knowing-forth, the act of discerning that goes ahead of belief. A precision worth preserving for English readers: wisdom descends from PIE *weyd- (the root of vidyā, vedanā, Latin videō, English vision), not from *ǵneh₃-. The conventional rendering "wisdom" therefore papers over an internal Sanskrit etymological distinction. The exact English cognate of prajñā is pro-cognition or, awkwardly, fore-gnosis; Greek's gnōsis — borrowed directly into English — is prajñā's closest one-word cognate; recognize is the cognate of saṃjñā; wisdom is the cognate of vidyā. The conventional translations cross the etymological lines, but the English reader who tracks these threads sees a network of distinctions the Chinese loses.
Prajñā is the fifth and last of the object-determining mental factors (viniyata, 別境五) in Yogācāra and the most-canonically-named factor in the Theravāda contemplative path: paññindriya (faculty), paññābala (power), dhammavicaya-sambojjhaṅga (the awakening factor of investigation-of-dhammas), sammā-diṭṭhi (the path-limb of right view). Asaṅga's Abhidharma-samuccaya defines it as upaparīkṣya eva vastuni dharmāṇāṃ pravicayaḥ — "with respect to the very same object being investigated, the discerning-among-dharmas" — with function saṃśaya-vyāvartana-karmikā: cutting away of doubt. Two doctrinal points are encoded by the brief Sanskrit. First, the particle eva — "the very same" — is load-bearing: prajñā's object is the same object samādhi (→#17) has stabilized, not a different one. This is the Sanskrit-textual root of 止觀雙運 (śamatha-vipaśyanā-yuganaddha, the union of stilling and insight): not a Mahāyāna elaboration but already encoded in Asaṅga's word choice. Samādhi holds the object steady; prajñā discerns within that same object. Second, the function clause shifts mode. The preceding cetasikas all carry X-sanniśrayadāna clauses ("provides basis for the next link"); prajñā alone carries saṃśaya-vyāvartana — outward-acting removal of obstacle. The cultivation chain terminates and turns outward at prajñā: no further cetasika is to be propped up; the work now is to remove what blocks seeing-as-it-is.
Visuddhimagga XIV.7 — placed at the chapter's framing position rather than interleaved with the cetasika list — names paññā's characteristic as dhamma-sabhāva-paṭivedha ("penetrating the intrinsic natures of dhammas") and its function as moha-andhakāra-viddhaṃsana (destruction of the darkness of delusion that obscures dhamma-natures). Paṭivedha (penetration) is the Pāli for what Asaṅga names pravicaya (discernment); both name the same act under slightly different metaphors — discrimination into something. The Visuddhimagga gives the proximate cause as samādhi, citing the canonical Pāli formula samāhito yathābhūtaṃ pajānāti ("the concentrated knows things as they are"). The architectural mirror is exact: Asaṅga gives samādhi's function as jñāna-sanniśrayadāna (basis for jñāna); the Visuddhimagga gives paññā's proximate cause as samādhi. Same structural claim, opposite vantages. The Pāli moha (delusion) is broader than Asaṅga's saṃśaya (doubt) — doubt is one mode of delusion among others; the Visuddhimagga generalizes the obstacle that paññā eradicates. North and south traditions converge on the samādhi → prajñā / paññā sequence, with prajñā defined as the discriminating-penetrating cognitive operation that breaks the obscuration.
Prajñā is morally graded by what it discerns and what guides it: when correctly aimed, it issues right view; when misaimed, it issues the five views (pañca-dṛṣṭi) — including satkāya-dṛṣṭi, the discerning-but-mistaken identification of the ālaya-vijñāna's seeing-portion as a "self." This is why prajñā is the only object-determining mental factor that manas (→#7, the seventh consciousness, the kliṣṭa-manas) takes up: the I-grasping at the heart of saṃsāra is not blind; it is a discerning, articulated, pseudo-rational grasp that uses prajñā's discriminating power in the wrong direction. The persistence and subtlety of self-grasping is, structurally, the persistence of prajñā operating with mistaken aim. Prajñā also has a kleśa-yoked corruption pair in the upakleśa range: asaṃprajanya (→#54 不正知, kleśa-saṃprayuktā prajñā) — prajñā operating in conjunction with affliction such that body, speech, and mind move without clear seeing. The two faces of prajñā — the discerning power that eradicates doubt, and the same power yoked to affliction — show that prajñā is morally mode-sensitive in a way that bare cognitive factors are not. The Saṃdhinirmocana-sūtra's definition of vipaśyanā through five operations (忍 / 樂 / 慧 / 見 / 觀) places prajñā (慧) at the center of the five, with vipaśyanā itself being prajñā's active deployment in meditation. At full purification, prajñā transforms into the pratyavekṣaṇā-jñāna (妙觀察智, Wisdom of Marvelous Investigation) — prajñā's discriminating function fully cleared of moha, operating with samādhi's stability as ground.
Discerning Wisdom — with respect to the very same object that has been investigated, the discriminating-among-dharmas: this is its nature. To cut away doubt: this is its function.
譯translator's note
譯者按： 結構分析詳 S3-P08。慧（prajñā，本條 #18）為別境五心所中唯一與末那（→#7）相應之條目——第七識以辨擇之慧誤執阿賴耶見分為「我」，故我執非盲目而為帶 prajñā 之頑固；慧之染位於隨煩惱段為不正知（→#54 asaṃprajanya = kleśa-saṃprayuktā prajñā）—— 同一心所（cetasika），染淨二用：清淨 prajñā 為解脫終端之對外-acting tool，染污 prajñā 為輪迴最頑固之 articulator。