瑜伽師地論 無尋無伺地 · 無尋無伺地：尋伺俱歇，從二禪到有頂——看的是離欲的根，不是現行的相
教理單元（定義型地）。地05 無尋無伺地不另立本體——它與地03、地04 共一套五門（三地合說）。本單元把它在「尋伺坐標」上的位置標清楚，並拈出兩個最要緊的判準，再指回共本文。
論怎麼定義它
「從第二靜慮，餘有色界及無色界全，名無尋無伺地。此中由離尋伺欲道理故，說名無尋無伺地，不由不現行故。」（本論）
從第二靜慮起，往上一切色界、乃至無色界全部（直到非想非非想處），都屬「無尋無伺地」。在尋伺這把尺上，這是粗細俱歇的最上一段。
關鍵一：看的是『離欲的根』，不是『現行的相』
論特意點破一個極易誤會處：叫它「無尋無伺」，憑的是「離尋伺欲」這個道理（已斷離尋伺的貪），不是憑「尋伺這會兒沒現行」。為什麼要這樣立？論自己舉了兩面：
「未離欲界欲者，由教導作意差別故，於一時間亦有無尋無伺意現行。已離尋伺欲者，亦有尋伺現行。如出彼定、及生彼者。」（本論）
——還沒離欲界欲的人，偶爾也會有無尋無伺的念頭閃過；已離尋伺欲的人（譬如出了定、或生在彼地者），偶爾也還會有尋伺現行。可見『一時的有無』靠不住，修證論的是斷沒斷那個根。這一判準，是整個尋伺三地分判的命脈。
關鍵二：無漏初靜慮，何以也叫「有尋有伺」
順著同一判準，論拈出一個極要緊的例外：
「若無漏界有為定所攝初靜慮，亦名有尋有伺地。依尋伺處法，緣真如為境入此定故，不由分別現行故。」（本論）
無漏的初靜慮明明已極深細，卻仍叫「有尋有伺」——因為它是「依尋伺處之法、緣真如而入」，不是憑粗分別現行。這一句把「尋伺」從凡夫定一路通到無漏聖定：尋伺之名，定於「依何法、離何欲」，不定於相之動靜。此義跨通三地，是讀無尋無伺地時不可略過的一筆。
指回共本文
無尋無伺地的「界·相·如理作意·不如理作意·雜染」五門義理，與有尋有伺地、無尋唯伺地合說，不另立、不重出——詳見 03-01 界施設 ～ 03-05 雜染。本單元只標其坐標位置與兩大判準；五門全幅，請於地03 共本文讀取。
A doctrine-pointer unit (a definition-type stage). Stage 05, the Stage with Neither Applied nor Sustained Thought, sets up no substance of its own — it shares one set of five gates with Stage 03 and Stage 04 (the three stages are expounded together). This unit marks clearly its position on the "applied-and-sustained-thought coordinate," draws out the two most essential criteria, and then points back to the shared main text.
How the Treatise Defines It
「從第二靜慮，餘有色界及無色界全，名無尋無伺地。此中由離尋伺欲道理故，說名無尋無伺地，不由不現行故。」 tr. "From the second dhyāna, the remainder of the form realm and the whole of the formless realm are called the Stage with Neither Applied nor Sustained Thought. Herein it is by reason of freedom from the craving for applied and sustained thought that it is called the Stage with Neither Applied nor Sustained Thought — not by reason of their non-operation." 〔the treatise〕
From the second dhyāna upward, the whole of the form realm and even the whole formless realm (up to the sphere of neither-perception-nor-non-perception) belong to the "Stage with Neither Applied nor Sustained Thought." On the measure of applied and sustained thought, this is the topmost segment, where coarse and fine are both at rest.
The First Key: What It Looks To Is the "Root of Freedom from Craving," Not the "Aspect of Present Operation"
The treatise deliberately breaks open a point exceedingly easy to mistake: to call it "neither applied nor sustained thought" rests on the reason of freedom from the craving for applied and sustained thought (the craving for applied and sustained thought having been cut and forsaken), not on "applied and sustained thought not operating just at this moment." Why establish it this way? The treatise itself gives both sides:
「未離欲界欲者，由教導作意差別故，於一時間亦有無尋無伺意現行。已離尋伺欲者，亦有尋伺現行。如出彼定、及生彼者。」 tr. "For one not yet free of the craving of the desire realm, by a particular attention under instruction there is at one time an operation, too, of a mind neither applied nor sustained. For one already free of the craving for applied and sustained thought, there is also an operation of applied and sustained thought — as when he emerges from that attainment, or is born onto that level." 〔the treatise〕
— One not yet free of the craving of the desire realm will at times, too, have a thought neither applied nor sustained flit past; one already free of the craving for applied and sustained thought (for instance, one who has emerged from the attainment, or is born onto that stage) will at times still have applied and sustained thought in operation. Plainly, "momentary presence or absence" cannot be relied upon: what practice-realization looks to is whether or not that root has been cut. This criterion is the very lifeline of the whole threefold division by applied and sustained thought.
The Second Key: Why the Uncontaminated First Dhyāna Is Also Called "With Both Applied and Sustained Thought"
Following the same criterion, the treatise draws out an exceedingly important exception:
「若無漏界有為定所攝初靜慮，亦名有尋有伺地。依尋伺處法，緣真如為境入此定故，不由分別現行故。」 tr. "The first dhyāna subsumed under the conditioned attainment of the uncontaminated realm is also called the Stage with Both Applied and Sustained Thought. For it is by depending on the dharmas that are the ground of applied and sustained thought, and taking suchness as object, that one enters this attainment — not by reason of the operation of discrimination." 〔the treatise〕
The uncontaminated first dhyāna is manifestly already exceedingly deep and fine, yet is still called "with both applied and sustained thought" — because it is one that "depends on the dharmas that are the ground of applied and sustained thought and enters by taking suchness as object," not by the operation of coarse discrimination. This line carries "applied and sustained thought" all the way through, from the concentration of the ordinary being to the uncontaminated concentration of the noble one: the name "applied and sustained thought" is fixed by "which dharmas one depends on, which craving one is free of," and is not fixed by the movement or stillness of the aspect. This sense runs across all three stages, and is a stroke not to be passed over when reading the Stage with Neither Applied nor Sustained Thought.
Pointing Back to the Shared Main Text
The doctrine of the five gates of the Stage with Neither Applied nor Sustained Thought — element, characteristic, attention in accord with principle, attention contrary to principle, and defilement — is expounded together with the Stage with Both Applied and Sustained Thought and the Stage with Sustained Thought Only; it is not set up separately, nor repeated — see in full 03-01 Designation of Elements through 03-05 Defilement. This unit only marks its position on the coordinate and its two great criteria; for the full span of the five gates, read them in the shared main text of Stage 03.