虛空Space-as-designation
無為法之首。「色之缺無」（*rūpa-abhāva*）為體，「容受一切作用」（*sarva-kṛtya-avakāśatā*）為用——非實有色法之外另立一空，乃於有色法所不及處假立「容受」之名。
漢zh · Xuanzang 譯
無為法之首。「色之缺無」（rūpa-abhāva）為體，「容受一切作用」（sarva-kṛtya-avakāśatā）為用——非實有色法之外另立一空，乃於有色法所不及處假立「容受」之名。
經
無為作為阿毘達磨之獨立本體範疇（asaṃskṛta-dharma），於阿含／尼柯耶不作明確列位；其經藏概念線索可由禪定所緣詞群追溯，如ākāśānañcāyatana（空無邊處）為四無色定之首，以虛空為所緣之禪定境（《雜阿含經》卷十七等多處散見），然此類用法為現象的教證描述（虛空作為禪定 ālambana 或物理性 ākāsa-dhātu 空界），非本體「無為」之 dharma 立位。論藏將此現象學重編為獨立本體範疇，乃 Sarvāstivāda 阿毘達磨時期始見三無為（虛空／擇滅／非擇滅）；瑜伽行派進一步擴為六（《大乘百法明門論》）／八（《阿毘達磨集論》），並於《成唯識論》卷二系統重判為假立（prajñapti）。
[大乘] 《楞嚴經》卷九（T19n0945, T19.0147b09）：
當知虛空生汝心內，猶如片雲點太清裏。
——虛空非外在客觀容器，乃心中所現之相分；「片雲點太清」之喻倒置常識（一般以為心於空中起，此云空於心中起），與下文《成唯識論》卷八「心等變似虛空等相，隨心生故」之依他起判攝同向。
論
虛空之論藏定義由淺入深五層：
《大乘五蘊論》（T31n1612, T31.0850a19，世親早期前唯識立場）：
云何虛空？謂若容受諸色。
——四無為列（《大乘五蘊論》 缺不動／想受滅）中之最簡形式，承 Vaibhāṣika 之「容受諸色」為定義要核。
《大乘阿毘達磨雜集論》卷二（T31n1606, T31.0702b23，安慧釋《集論》）：
虛空者，謂無色性，容受一切所作業故。
——此措辭與《阿毘達磨集論》梵本（rūpa-abhāvaḥ sarva-kṛtya-avakāśatām upādāya）為逐語素仿譯：「無色性」＝ rūpa-abhāva，「容受一切所作業」＝ sarva-kṛtya-avakāśatā。
《顯揚聖教論》卷一（T31n1602, T31.0484c01–02，無著菩薩造）：
虛空者，謂諸心心法所緣外色對治境界性。
——無著於《顯揚》瑜伽行派-distinctively 重詮：虛空非物理空間，乃心心所之所緣，是外色之對治境界（pratipakṣa-viṣayatā）——禪修以ākāśa作意破除對外色之執取。此一義 Asg 集論本身未明示，乃《顯揚》之瑜伽行派推進。
《成唯識論》卷二（T31n1585, T31.0006c05–17）以「五依真如假立」框架統攝六無為，此為cluster之doctrinal 錨 passage：
然契經說，有虛空等諸無為法，略有二種：一、依識變假施設有……二、依法性，假施設有。謂空、無我所顯真如，有、無、俱非，心言路絕，與一切法非一、異等，是法真理，故名法性。離諸障礙，故名虛空；由簡擇力，滅諸雜染，究竟證會，故名擇滅；不由擇力，本性清淨，或緣闕所顯，故名非擇滅；苦、樂受滅，故名不動；想、受不行，名想受滅。此五皆依真如假立，真如亦是假施設名。
——《成唯識論》將六無為之「假立」分為兩 modes：①依識變假施設（識所變似之相）②依法性假施設（真如之面相）。後五（虛空／擇滅／非擇滅／不動／想受滅）皆屬②，為真如之面向命名——離諸障礙之面向曰虛空，簡擇之面向曰擇滅……。真如自身亦是假施設名，非心外實體（→#100 真如承擔 the 統合者 role）。
《成唯識論》卷八（T31n1585, T31.0046c13–17）以三性框架另詮虛空：
心等變似虛空等相，隨心生故，依他起攝；愚夫於中，妄執實有，此即遍計所執性攝；若於真如，假施設有虛空等義，圓成實攝。
——同一虛空於三性框架下分屬三層：作為心變相分（依他起）、作為被執實之對象（遍計所執）、作為真如之假施設義（圓成實）。卷二之「五依真如假立」與卷八之三性分判互補：卷二從「無為 vs 有為」之本體軸、卷八從「依他／遍計／圓成」之認知軸——兩軸於虛空交會。
按：論藏五層由淺入深：《大乘五蘊論》 之 Vaibhāṣika-形式「容受諸色」→ 《大乘阿毘達磨雜集論》 之 Asg 逐語素仿譯「無色性容受一切所作業」→ 《顯揚聖教論》 之瑜伽行派認知-antidote 重詮「外色對治境界性」→ 《成唯識論》卷二之 tathatā-面相假立「離諸障礙」→ 《成唯識論》卷八之三性分位（依他／遍計／圓成）。卷二「此五皆依真如假立」一句為本cluster之架構樞紐——百法將 Asg 八無為（三層真如分善／不善／無記＋五止息）合為六（一真如統＋五止息），《成唯識論》卷二即此合併之義理許可。本條（#95）為cluster之首，承擔「假立形態雙分」之articulate 工作；#96／#97／#98 之三框架樣板由本條之梵段表鎖定；#100 真如承擔 the 統合者 role.
梵saṃskṛta
ākāśa < ā-（向、強化前綴）+ √kāś（顯、現、光）+ -a——「彰顯之處」「光之所在」。同根詞 prakāśa「光明」、ā-vakāśa「空隙、機會」。⚠️ √kāś 之印歐祖語同源不甚明確：偶見二手文獻提議 *(s)kewh₁- 「光、閃」，然 Mayrhofer / Lubotsky 未予 secure；保留為 Indo-Aryan-internal，不上推印歐祖語。
asaṃskṛta < a-（否定）+ saṃskṛta（已造作，過去分詞）——「不被造作」「無為」。saṃskṛta < sam- + √kṛ（作）+ -ta。⚠️ √kṛ 之印歐祖語重構 *kʷer- 「作、造」存在但有爭議：英文 create（拉丁 creare）、culture（拉丁 colere）、cosmos（希臘 κόσμος）多歸別根，與 √kṛ 之關係為間接者；保留 ⚠️ 不上推為 secured 同源鏈。
《阿毘達磨集論》（Abhidharma-samuccaya，Pradhan 校本，asaṃskṛta-dharma 段，[Abhidh-s 13]）：
ākāśaṃ katamat / rūpābhāvaḥ sarva-kṛtya-avakāśatām upādāya //
何為虛空？以容受一切作用之故（sarva-kṛtya-avakāśatā ＝為一切作用提供場所之屬性），即色之缺無（rūpa-abhāva）。Asg 以負面定義（rūpa-abhāva）配正面功能子句（sarva-kṛtya-avakāśatā）——upādāya「以……之故」之構式為Asg prajñapti-style 之 signature：將功能子句吸收為負面定義之因而非「相＋業」並列，以保留無為之 prajñapti 性格。
無為類於Asg之定義式有別於心所——無 svabhāva / karman 雙結構（心所為「X-svabhāvā / Y-karmikā」格式）。此格式之精簡本身即為義理立場：勿予無為以「自體＋業用」之雙軸描述，免落實有之執。
| 文本 | 虛空為…… | Frame |
|---|---|---|
| Asg [Abhidh-s 13] | rūpa-abhāva + sarva-kṛtya-avakāśatā | Vaibhāṣika-style negative-with-功能性 |
| 顯揚卷一（T31.0484c01–02） | 心心法所緣外色對治境界性 | 瑜伽行派認知-antidote-field |
| 《成唯識論》卷二（T31.0006c12–13） | 離諸障礙（真如之面相） | tathatā-面相假立 |
⚠ In Review · 名稱衝突（→#70 法處所攝色之 ② ābhyavakāśika 極迥色）：本條 #95 之 ākāśa（ā- + √kāś）為無為（unconditioned, asaṃskṛta），與 #70 法處所攝色 sub-type ②ābhyavakāśika（abhi-ava- + √kāś + -ika，「居於空之屬」「於極遠處所現之色」）為有為色法之假立（有為 prajñapti-rūpa）。同一 √kāś 根，前綴與所攝層級根本不同——一為無為假立（依真如），一為色法假立（依色心分位）。讀者當警此名根近似而本體異層之陷阱。
按：三框架表 Asg／顯揚／《成唯識論》卷二為本詞族之方法論樣板——#96 擇滅／#97 非擇滅／#98 不動滅之三框架結構皆由本表鎖定（→#96 #97 #98）。Asg → 顯揚之推進為瑜伽行派-distinctive：Asg 承 Vaibhāṣika 之負面加功能定義，顯揚將其重置為認識論進路（外色對治境界），即虛空非「有色法外另立之空間」而為「破色執之 meditation-object」。《成唯識論》卷二再進一層，將虛空與其他四止息合判為真如之五面相命名——此一合併許可百法 8→6 之架構收攝（→#100 承擔 the 統合者）。同時，本條與 #71 得闡明之假立框架成對照：#71 闡明「依色心分位假立」（依有為法之配置差別）；本條闡明「依真如假立」（依無為法性之面相命名）——同樣 prajñapti-sat 機制，二異本體層（有為分位 vs 無為法性），不可混同。
巴pāḷi
於上座部阿毘達磨，虛空不立為 asaṃkhata。南傳唯立 Nibbāna 為單一 asaṃkhata-dhamma（Vism XVI；《Abhidhammattha-saṅgaha》VI.34）；空之現象學散入三條件性處理層：①paññatti（概念）、②dhātu（界、元素）、③pariccheda-rūpa（界劃色）——三者皆有為，無一立位於 paramattha-asaṃkhata。此乃南北於本cluster 之範疇之架構層級分歧——非語詞分歧，乃法目層級之系統設計差異：瑜伽行派立六（或 Asg 八）asaṃskṛta，南傳唯立一。
經
阿含／尼柯耶共傳階層，「虛空」之經典出現多為禪定 ālambana（如 ākāsānañcāyatana 空無邊處）或物理 ākāsa-dhātu 空界，皆於有為現象學 範疇內處理；asaṃkhata 範疇之獨立教證僅關於 Nibbāna，未及虛空。本條巴段之跨傳承分歧乃論藏層級之系統地分歧，非可由經藏共傳教證直接闡明。
論
南傳對應論——三條件性處理層之分散：
①ākāsa-paññatti（空之假名，《Abhidhammattha-saṅgaha》VIII.4）：列為六 paññatti 子類之一（santati- / samūha- / ākāra- / kāla- / pajā- / nāma-paññatti + ākāsa-paññatti），但 paññatti 整類不入勝義法（paramattha-dhamma）名單——非 paramattha 即非 asaṃkhata 候選。
②ākāsa-dhātu（空界）：作為四大（paṭhavī / āpo / tejo / vāyo）之外之第五元素或色法之間隔，屬有為色法現象學之描述。
③pariccheda-rūpa（界劃色，Visuddhimagga XIV.63）：28 色法中之「界劃」一類——色法團聚之間之邊界空間，作為 upādā-rūpa（依大色之色）。有為，色聚輔助項。
⚠ In Review · Vism XIV.63 pariccheda-rūpa 之確切 Pāli 措辭為「kammādisamuṭṭhānānaṃ rūpānaṃ paricchedo」（業等所生諸色之界劃）類；本段未字元精準校勘，引為段落參照而非逐字引文。
三層俱為有為：paññatti 為概念施設、dhātu 為色界元素、pariccheda-rūpa 為色聚界劃。瑜伽行派將有為層之 pariccheda 類 phenomenon 重編入 #70 法處所攝色（極迥色等），同時於無為層另立 ākāśa-asaṃskṛta（本條 #95）——一同根詞於兩本體層各立一位。南傳拒此雙層分立，唯保有為層之 pariccheda-rūpa 與 paññatti，並以 Nibbāna 為唯一 asaṃkhata。
按：南北於本cluster 之分歧為 baifa 全 100 條中最深之範疇之架構分歧——大於 #60–#70 色法之 28-vs-11 分歧（→#60），大於 #71–#94 不相應行之 24-vs-0 分歧（→#71）。瑜伽行派立 6/8 asaṃskṛta（多元無為加真如統），南傳立 1 asaṃkhata（Nibbāna* 唯一）；非語詞或內容之異，乃對「無為應如何 categorize」之系統決定。本條為cluster 之首，闡明此南北分歧之頭一輪；#100 真如承擔該分歧之一元論-vs-pluralism 終極形態（→#100）。*
漢綜述zh-synthesis
「虛空」之梵文 ākāśa 為 ā-（強化前綴）+ √kāś（「顯、現、光」）+ -a——「彰顯之處」「光之所在」。同根詞：prakāśa（「光明、顯現」）、avakāśa（「空隙、機會」）。⚠️ √kāś 之印歐祖語同源不甚明確：偶見提議 *(s)kewh₁-「光、閃」，然 Mayrhofer EWAIA 與 Lubotsky Indo-Aryan Inherited Lexicon 未予 secure；保留為印度雅利安語系內部，不上推印歐祖語。asaṃskṛta（無為）< a-（否定）+ sam- + √kṛ（「作」）+ -ta（過去分詞）——「不被造作」；√kṛ 之印歐祖語重構 *kʷer- 有爭議，保留 ⚠️。漢字「虛空」：「虛」= 空洞、缺無，「空」= 無礙、容受——雙字並用強化「無色法之容受性」義，高於 ākāśa 之「光顯之處」本義，為玄奘義理加固之漢譯策略。
虛空為無為法之首（6 無為之第一），承擔本 cluster 之三項架構任務：①8→6 架構攝合：《集論》原立 8 無為（三層倫理面相之真如＋五止息），百法合三層真如為一統，收攝為 6——此合併由《成唯識論》卷二「此五皆依真如假立」一語架構許可（→#100 承擔統合者角色）。②「五依真如假立」教義：《成唯識論》卷二（T31n1585, T31.0006c12–13）明判後五無為（虛空、擇滅、非擇滅、不動、想受滅）皆為「依法性假施設有」形態——真如之面相命名，依不同角度之假施設，而非獨立實有；「此五皆依真如假立，真如亦是假施設名」為本 cluster 之義理樞紐（→#100）。③Asg／顯揚／《成唯識論》三框架方法論：本條之梵段三框架表（rūpa-abhāva + 功能子句 → 認知 antidote 重詮 → tathatā 面相假立）為 #96 #97 #98 之方法論樣板（→梵段）。本條自身之義理核心：「色之缺無」（rūpa-abhāva）為體，「容受一切作用」（sarva-kṛtya-avakāśatā）為功能——非實有色法之外另立一空，乃於有色法所不及處假立「容受」之名，依真如之「離諸障礙」面相而立（《成唯識論》卷二：「離諸障礙，故名虛空」）。《成唯識論》卷八三性判攝：心等變似虛空等相（依他起）、被執實有（遍計所執）、真如假施設義（圓成實）——卷二與卷八兩軸（無為 vs 有為本體軸 + 依他／遍計／圓成之認知軸）於本條交會。
南傳唯立 Nibbāna 為單一 asaṃkhata-dhamma（Vism XVI；Abhidhammattha-saṅgaha VI.34）；虛空於南傳分散入三有為層：ākāsa-paññatti（空之假名，不入勝義法名單）、ākāsa-dhātu（空界，有為元素）、pariccheda-rūpa（界劃色，Visuddhimagga XIV.63，色聚邊界，有為）。三層俱有為——南傳拒絕瑜伽行派之「將空之施設性從概念層提升至無為 dharma 層」此一判攝移動。此乃 6-對-1 無為 cluster 南北範疇-架構分歧之首條闡明，分歧詳見各條巴段（→#100 收攝終局闡述）。
虛空為本 cluster 之教學入口。《楞嚴經》卷九「當知虛空生汝心內，猶如片雲點太清裏」倒置常識（通常以為心於空中起，此云空於心中起）：禪定中所覺之「開廣無礙」乃虛空假立（真如「離諸障礙」面相之顯現），非真如自身。真如（→#100）於喧鬧之心與廣闊之心中同等在場；「開廣」為現象學成就，真如為其底層原理。將禪定中之空曠感誤認為真如，乃本條之修行保護所指向之誤識。
「虛空」玄奘既譯。英譯 Space-as-designation 以 Space 對 ākāśa 之容受性義，以 -as-designation 明示 prajñapti 性格（依真如假立，非實有 dharma）。⚠️ 注意 #70 法處所攝色 sub-type ② ābhyavakāśika（極迥色）亦出同一 √kāś 根——一為無為假立（依真如），一為有為色法假立（依色心分位），同根異層，勿混。
虛空 ——於離諸障礙之 dharmatā-面相中，假立「虛空」（ākāśa，Pāli ākāsa）之名；性為色法缺無（rūpa-abhāva）所示之容受性（sarva-kṛtya-avakāśatā），業為破外色執之認識論對治；不變不滅之究竟實，依真如（→#100）之離諸障礙面相假立。
英綜述en-synthesis
Sanskrit ākāśa compounds ā- (intensive prefix) + √kāś "to shine, to appear, to be visible," literally "the place of shining" or "the open expanse where things can appear." Cognate within Sanskrit: prakāśa "luminosity, manifestation," avakāśa "interval, opportunity, room-to-appear." The PIE chain for √kāś is uncertain; secondary literature occasionally proposes *(s)kewh₁- "to gleam, to shine," but Mayrhofer's Etymologisches Wörterbuch des Altindoarischen and Lubotsky's Indo-Aryan Inherited Lexicon do not secure the reconstruction. Honest position: Indo-Aryan-internal cognate set is rich; PIE upstream is open. The compound asaṃskṛta — a- (privative) + saṃ- + √kṛ "to make" + -ta (past participle) — means "not put-together, unconditioned." For √kṛ, the PIE root *kʷer- "to make" is sometimes adduced as a parallel to Latin creāre (English create) and Latin colere (English culture), but the boundary is contested in the etymological literature; the Latin terms more securely derive from *ker- / *kel- family branches that may or may not connect to Indo-Iranian √kṛ. Marking ⚠️ rather than asserting kinship is the right discipline.
Ākāśa is the first of six unconditioned dharmas (asaṃskṛta) in the Yogācāra 100-list and the cluster's paradigm-setter. Asaṅga's Abhidharma-samuccaya defines it negatively-with-functional: "the absence of rūpa taken as the room-providing for all activities" (rūpābhāvaḥ sarva-kṛtya-avakāśatām upādāya). The upādāya construction — "by way of, on the basis of" — absorbs the functional clause into the negative definition's causal grounding, encoding prajñapti-status into the formula's syntax: ākāśa is not a positive thing with a function; it is a designation imputed because the absence of rūpa provides room. The cluster has two architectural distinguishers from prior baifa clusters. First, the 8-versus-6 collapse: Asg lists 8 unconditioneds (tathatā threefold by ethical aspect — wholesome / unwholesome / indeterminate dharmas — plus 5 cessations); the Daśa-bhūmi-mukha (《大乘百法明門論》, Vasubandhu) collapses to 6 by reducing the threefold tathatā to one. The collapse is doctrinally licensed by Cheng Weishi Lun fascicle 2's claim 「此五皆依真如假立」 — the five cessations are all designations dependent on tathatā, so the system can be presented either as 8 (with tathatā tripled by ethical aspect) or as 6 (with tathatā unified at the bottom). Baifa adopts the 6, retaining the unifier role for #100 tathatā. Second, prajñapti-sat re-applied at the unconditioned layer: where #71's prāpti and the rest of the 不相應行 cluster are designations on configurational differentials of conditioned dharmas (依色心分位假立), the six unconditioneds are designations on aspects of unconditioned dharma-nature (依真如假立). CWS 卷二 surfaces the bifurcation explicitly: ① 依識變假施設有 (designation by mind-transformation, the mode for #70's ābhyavakāśika-class projections under the paratantra lens) ② 依法性假施設有 (designation by dharmatā, the mode for #95–#99). Ākāśa belongs to mode ②. The same prajñapti-sat machinery operates at two ontological strata; conflating the strata loses the cluster's whole architectural point.
Convergence is the wrong word for this entry; the relationship to Theravāda is the deepest categorial-architectural divergence in baifa. Yogācāra (extending the Sarvāstivāda baseline of three) lists six unconditioneds; Theravāda lists one (Nibbāna alone, per Visuddhimagga XVI and Abhidhammattha-saṅgaha VI.34). The phenomenology is not in dispute — both traditions agree that space exists in some sense, that analytical cessations of kleśa occur, that fourth jhāna is immovable, that saññā-vedayita-nirodha can be entered, that there is a suchness to phenomena. What divides them is whether these phenomena merit separate dharma-status. Yogācāra says yes (as imputations on tathatā); Theravāda says no (subsume under conditioned-event-status or paññatti-status). For ākāśa specifically, Theravāda has three conditioned analogs at three different layers: ākāsa-paññatti (concept-only, excluded from the paramattha-dhamma scheme); ākāsa-dhātu (the space-element among the physical elements); and pariccheda-rūpa (the boundary-form between rūpa-clusters per Visuddhimagga XIV.63). All three are conditioned; none is asaṃkhata. The Yogācāra move that Theravāda rejects is the promotion of space's "designation-only" status from concept-layer to unconditioned-dharma-layer. Both agree space is "designation-only"; they disagree about whether designation-only-ness therefore counts as a kind of dharma at all. This pattern — categorial-architecture divergence at unconditioned strata — recurs in sharper form at #98 āniñjya and #99 saṃjñā-vedayita-nirodha, where Pāli has cognate terms (aneñjābhisaṅkhāra, saññāvedayitanirodha) but classifies them as conditioned rather than unconditioned. Same words, opposite verdicts. The opposite verdicts trace back to the architectural commitment: Yogācāra-pluralism (with tathatā unifier) vs. Theravāda-monism (with Nibbāna as sole unconditioned).
Ākāśa is the cluster's pedagogical entry-point because it is the most accessible misidentification. The image at Śūraṅgama-sūtra fascicle nine — "vast space arises within your mind, like a small cloud appearing in the clear sky" — inverts intuition: we usually think mind appears in space; here space appears in mind. The image is doctrinally aligned with CWS fascicle 8's reading that mind-transformations appear as space, taking paratantra-svabhāva as their ontological mode. The practitioner's risk lies in mistaking the expansive openness of a settled meditation for tathatā-realization. The expansive openness is closer to ākāśa-asaṃskṛta: it is what the receptivity-for-form looks like phenomenologically when the activity of grasping has thinned. Tathatā as principle (dharmatā, 法性) is the underlying suchness of all dharmas in all conditions — present equally when the mind is clamorous and when it is open, equally in kuśala and akuśala dharmas. The expansiveness is a phenomenology; tathatā is the principle of which all phenomenologies (open and clamorous alike) are aspects. The cluster's architectural point — that ākāśa is one aspect of tathatā (the un-obstructed-ness aspect, per CWS 卷二's 「離諸障礙」), not tathatā itself — is the practitioner's protection against this misidentification. Tathatā does not become "more present" in expansive sittings; the unconditioned does not vary with the conditioned states in which it is glimpsed.
Space-as-designation (ākāśa) — The absence of form, taken on the basis of providing room for all activities. Not external container, not positive substance: a designation imputed on the un-obstructed-ness aspect of dharma-nature. First of the six unconditioneds, paradigm-setter for the four cessations (#96–#98) and pointing forward to tathatā (#100) as the unifier on which all five rest.
譯translator's note
譯者按： 結構分析詳 S3-P13。本條為「無為」詞族之首，鎖定三項詞族共通結構：8→6 architectural collapse（Asg 三層真如攝合為一統，→#100 承擔 the 統合者）、「五依真如假立」教義（《成唯識論》卷二之 prajñapti-sat 統綱，#96 #97 #98 inheritance）、Asg／顯揚／《成唯識論》三框架方法論（梵段表為詞族樣板）；並於梵段表面與 #70 法處所攝色 ② ābhyavakāśika 極迥色之 √kāś 同根異層 collision（→#70），闡明同一 prajñapti-sat 機制於有為色法（依分位）對 無為法性（依真如）之雙層應用——本條與 #71 得共立 prajñapti-sat 雙層之詞族錨。