paricCheda 1 - apacCheda nyAya vaiShamya bhanga:

The shruti, according to the advaitin, reveals the world to be mithyA. Perception reveals it to be real. These two means of knowledge are accepted as valid by the advaitin, but when the two are in contradiction, which takes precedence? In the bhAmati, Sri VAchaspati MiSra has argued that shruti takes precedence, and cites a mImAmsa principle, apacCheda nyAya, in support.

In summary, apacCheda nyAya is a rule that is used to determine the relative strength of two non-simultaneous, mutually independent, contradictory cognitions. According to this maxim, the cognition that arises last (and is itself not sublated by another pramANa later) is stronger than the cognition that occured previously.

Sri AnandabodhAchArya, in his pramANamAla has argued that perception of the world first leads to the cognition of its existence. Later, upon the study of vedic scriptures and mental contemplation upon their subject matter, one understands that the world is mithyA. Because this knowledge occurs after the perception of the world, it overrules perception by apacCheda nyAya.

Before we proceed to review the application of the nyAya in the current context, it may be useful to understand it in its original context.

The context of apacCheda nyAya 
During the morning pressing of the soma (prAtassavanam) in the jyotiShToma sacrifice, the priests performing the sacrifice along with the sacrificer, walk from the location of the AhavanIya inside the house to the cAtvAla (a trench or pit, the earth from which is used to construct the mahAvedi or altar) outside, where the bahiShpavamAna hymn is to be sung.

shruti prescribes a very particular order and way by which the five officiating priests and the sacrificer need to proceed to that place. It is said that they need to walk in a single file, led by the adhvaryu in the front, followed by the prastotA, then the pratihartA, then the udgAta, then the brahmA and finally the yajamAna, the sacrificer. While walking thus, each person in the procession needs to grab hold of the tucked-up waist cloth of the person in front. If, for whatever reason, any one of the prastotA, pratihartA or udgAtA lets go (apacCheda, or disconnection) of the cloth, then depending on which particular priest has the apacCheda, certain expiatory rites are to be followed.

If the priest called the udgAta lets go, as an expiation, the current round of the sacrifice (called a prayoga) is completed without dakshiNA (ritualistic fees paid by the sacrificer to the officiating priests), and it is restarted from scratch a second time (with dakshiNA). If the priest called the pratihartA lets go, the expiation is that all the material wealth of the sacrificer is to be offered to the priests (sarvasva dakshiNA) in the current prayoga.

This arrangement raises a question, if there are multiple apacCheda-s in one prayoga, what is the expiation? If the two mutually independent nimitta-s (circumstantial causal factors) occur simultaneously, either expiation is permissible, but if they occur in sequence, Jaimini rules that the latter nimitta prevails in determining the specific expiation required - पौर्वापर्ये पूर्वदौर्बल्यं प्रकृतिवत् (mImAmsa sUtra 6.5.54).

The argument of advaitin-s prior to the nyAyAmRta
The use of apacCheda nyAya in the context of advaita was first adopted by Sri MaNDana MiSra, the author of brahma siddhi. VAcaspati MiSra, the author of bhAmati, taking the brahma siddhi argument as his basis, used this maxim to argue in the context of the commentary to the adhyAsa bhAShya, that because the knowledge of the self as limited as known from perception is contradictory to knowledge of the self as unlimited as revealed by shruti, and because the knowledge revealed by the shruti is logically subsequent to the knowledge revealed by perception, it is shruti-'s conclusion that overrules perception.

The advaitin uses the same principle to argue that as both shruti and the inference of the world's mithyAtva are logically subsequent to the perception of the world's reality, they should overrule perception.

They are logically subsequent to perception because a denial of reality presupposes an apparent comprehension of reality first. Thus perception, which reveals the reality of the world must necessarily come before the denial of reality conveyed by shruti and inference. Secondly, an understanding of shruti requires one to have heard the words first, and inference requires both that the hetu is perceived in the paksha, and that the hetu and sAdhya have been perceived to be invariably coexistent elsewhere. Thus both shruti and inference require perception to have occurred first. Due to these reasons, it is appropriate to hold that inference and shruti are logically consequent to perception.

That being the case, when the two (inference and shruti on one hand, and perception on the other) are in contradiction, by the application of apacCheda nyAya, the cognition revealed by shruti and inference should overrule the cognition revealed by perception. 

The argument of the nyAyAmRtakAra
The nyAyAmRtakAra disagrees and argues that the application of apacCheda nyAya is inadmissible in the scenario because of certain differences. In his view, there are three conditions for the application of apacCheda nyAya -
1) there is a sequence in the application of the pramANa-s,
2) the two pramANA-s are contradictory to each other,
3) despite the contradiction, as a rule, the former pramANa is not completely sublated by the application of apacCheda nyAya.

In the case of the jyotiShToma, all three conditions are met. There are two nimitta-s that occur in sequence, each of which is backed by a shruti injunction. There is a contradiction because if the udgAtR apacCheda and pratihartR apacCheda both occur, one is left with the doubt whether dakshiNA is payable or not. The udgAtR apacCheda requires that no dakshiNA is payable in the current prayoga, whereas the pratihartR apacCheda requires that everything is donated as dakshiNA in the current round.

Despite this, even if the expiation for the udgAtR apacCheda is overruled by the expiation of the pratihartR apacCheda on account of the latter taking precedence because that nimitta occurs later,  there are still instances where the former expiation has scope for application. Three such incidents are highlighted in the text (discussed below).Thus, he concludes that the validity of the prior injunction is not denied - it is merely not applicable in the current instance of the sacrifice.

However, in the context of advaita shruti and perception, apacCheda nyAya is inadmissible because the conditions for its operation are not met. While there is a sequence of pramANa-s (perception reveals the world's reality first, and later shruti/inference reveal its unreality), and they are contradictory to each other,  if it is held that apacCheda nyAya is admissible, perception ends up losing its status as a valid means of knowledge - in other words, the third condition for the application of this maxim is not met. Thus, he argues in a chapter titled apacCheda nyAya vaiShamya in the nyAyAmRta that apacCheda nyAya is inadmissible in this context.

The siddhikAra refutes this in this chapter of the advaita siddhi, titled apacCheda nyAya vaiShamya bhanga: - the refutation of the inadmissibility of apacCheda nyAya.

He says:
किं चापच्छेदन्यायेनाप्यागमस्य प्राबल्यम् | shruti is the stronger (means of knowledge), because of apaccheda nyAya.

यथा हि 'पौर्वापर्ये पूर्वदौर्बल्यं प्रकृतिव' दित्यधिकरणे उद्गात्रपच्छेदनिमित्तकादक्षिणयागेन परेण प्रतिहर्त्रपच्छेदनिमित्तकसर्वस्वदक्षिणयागस्य पूर्वसिद्धनिमित्तकस्य बाध इति स्थितम्,
यथा हि 'पौर्वापर्ये पूर्वदौर्बल्यं प्रकृतिव' दित्यधिकरणे Following the section from the pUrva mImAmsa sUtra-s (6.5.54) titled 'When there are two sequential (nimitta-s), the former is weaker, like in the current instance",
उद्गात्रपच्छेदनिमित्तकादक्षिणयागेन परेण प्रतिहर्त्रपच्छेदनिमित्तकसर्वस्वदक्षिणयागस्य पूर्वसिद्धनिमित्तकस्य बाध इति स्थितम् the performance of the sacrifice without dakshiNA, which is the expiation needed as a result of the udgAtR apacCheda, overrules the expiation needed as a result of the pratihartR apacCheda, which is the performance of the sacrifice where all of the sacrificer's material wealth is given away,
because the expiation resulting from the first occurring causal factor is deemed to have been overruled by the expiation resulting from the second causal factor.

तथेहापि उदीच्यागमेन पूर्वस्य प्रत्यक्षस्य बाध: | Similarly, it follows that here too, shruti, which reveals its object subsequent to perception's revelation, it is the prior perception that is overruled.

The opponent objects:
ननु - प्रतिहर्त्रपच्छेदनिमित्तकसर्वस्वदक्षिणयागस्य प्रतिहर्तृमात्रापच्छेदे, युगपदपच्छेदे, क्रमेणापच्छेदेऽपि प्रतिहर्त्रपच्छेदस्य पश्चात्वे च अवकाश इति युक्त: उद्गात्रपच्छेदनिमित्तकादक्षिणयागेन बाध:,
प्रतिहर्त्रपच्छेदनिमित्तकसर्वस्वदक्षिणयागस्य प्रतिहर्तृमात्रापच्छेदे, युगपदपच्छेदे, क्रमेणापच्छेदेऽपि प्रतिहर्त्रपच्छेदस्य पश्चात्वे च अवकाश Because the sacrifice involving the dakshiNA of all the material wealth has scope for application when one of the following occurs
1) the pratihartR apacCheda alone occurs, or
2) if the pratihartR apacCheda occurs simultaneously (with udgAtR apacCheda), or
3) if it occurs in sequence, the pratihartR apacCheda occurs last,

इति युक्त: उद्गात्रपच्छेदनिमित्तकादक्षिणयागेन बाध: Therefore, it is appropriate to hold that the sacrifice without dakshiNA occurring as a result of udgAtR apacCheda can overrule the sacrifice involving the dakshiNA of all material wealth occurring as a result of pratihartR apacCheda. 
अन्यथा 'यदि प्रतिहर्ता अपच्छिद्येत सर्ववेदसं दद्या' दिति शास्त्रमप्रामाणम् स्यात्, Otherwise, the scriptural injunction prescribing that "upon the occurrence of pratihartR apacCheda, sacrifice all the material wealth", would be rendered invalid, apramANa.

If there was no scope for its application, the validity of the scriptural injunction would be lost.

अत एव 'विप्रतिषेधाद्विकल्प: स्या 'दित्यधिकरणे द्वयोर्युगपदपच्छेदे विकल्प उक्त: | Therefore (in order to preserve the validity of either scriptural injunction), the mImAmsa sUtra (6.5.51) "Because there is conflict of texts, choosing either is optional" rules that where there is a simultaneous apacCheda, one can use the expiation for either option.

किञ्च 'यद्युद्गाता जघन्य: स्यात्पुनर्यज्ञे सर्ववेदसं दद्यादथेतरस्मि' न्नित्यधिकरणे उद्गात्रपच्छेदस्य प्रतिहर्त्रपच्छेदात्परत्वे उद्गात्रपच्छेदनिमित्तं पूर्वं प्रयोगं दक्षिणाहीनं संपाद्य कर्तव्यज्योतिष्टोमस्य द्वितीयप्रयोगे 'तद्दद्यात्यत्पूर्वस्मिन् दास्यन् स्यात् ' इति श्रुत्युक्ता या दक्षिणा सा पूर्वभाविप्रतिहर्त्रपच्छेदनिमित्तकपूर्वप्रयोगस्थसर्वस्वदित्साया अबाधेन सर्वस्वरूपैव, न तु या ज्योतिष्टोमे नित्या द्वादशशतरूपा |
किञ्च 'यद्युद्गाता जघन्य: स्यात्पुनर्यज्ञे सर्ववेदसं दद्यादथेतरस्मि' न्नित्यधिकरणे Moreover, from the sUtra (6.5.55) titled "When the udgAtR (apacCheda) occurs last, perform the sacrifice again with the dakshiNA of all material wealth, as in the case of the other",
उद्गात्रपच्छेदस्य प्रतिहर्त्रपच्छेदात्परत्वे उद्गात्रपच्छेदनिमित्तं पूर्वं प्रयोगं दक्षिणाहीनं संपाद्य it is said that, when the udgAtR apacCheda occurs after the pratihartR apacCheda, then after completing the first round of the sacrifice without any dakshiNA, pursuant to the expiation required for the udgAtR apacCheda,
कर्तव्यज्योतिष्टोमस्य द्वितीयप्रयोगे 'तद्दद्यात्यत्पूर्वस्मिन् दास्यन् स्यात् ' इति श्रुत्युक्ता या दक्षिणा the dakshiNA, which is to be given the second time the jyotiShToma is performed, is, in accordance with the shruti injunction "perform a sacrifice again with the dakshiNa that was determined to be given the first time"
सा पूर्वभाविप्रतिहर्त्रपच्छेदनिमित्तकपूर्वप्रयोगस्थसर्वस्वदित्साया अबाधेन सर्वस्वरूपैव, is certainly all the material wealth, because that has not been overruled, having been the desire of the sacrificer following the occurrence of the pratihartR apacCheda in the first round of the sacrifice (before the udgAtR apacCheda occurred).
न तु या ज्योतिष्टोमे नित्या द्वादशशतरूपा | and not the the regular dakshiNA prescribed for jyotiShToma, which is 112 (cows).

तस्मान्न प्रतिहर्त्रपच्छेदस्य सर्वथा बाध:, Therefore, the absolute invalidation of the expiation following pratihartR apacCheda does not occur.
किं तु प्रयोगान्तरे निक्षेप इत्युक्तम्, उक्तं हि टुप्टीकायाम् - 'तस्य प्रयोगान्तरे निक्षेप ' इति | Rather, that expiation occurs in the next round of the sacrifice. As has been said in the TupTIkA (of KumAriLa BhaTTa),"It is taken to the next round".

अपिच क्रमिकनिमित्तद्वयेन क्रमेणादक्षिणसर्वस्वदक्षिणयो: प्रयोगयो: संभवेन विरोध एव नास्ति; यथा बदरीफले क्रमिकनिमित्तवतो: श्यामरक्तयो: | Further, there is no contradiction in holding that, where the causal factors occur sequentially, the sacrifice is without dakshiNA first and later the same sacrifice has the dakshiNA of all wealth. It is like the example of a berry, and it is no contradiction to say that it starts off green first and later turns red.

उक्तं ह्यपच्छेदाधिकरणे - 'नैमित्तिकशास्त्रस्य ह्ययमर्थ:, 'निमित्तोपजननात् प्रागन्यथाकर्तव्योऽपि क्रतुर्निमित्ते सत्येवं कर्तव्य: ' इति | This has been said in the apacCheda chapter of shAstra dIpikA of PArthasArathi MiSra (6.5.19) - "The intended meaning of the scripture dealing with circumstantial occurrences is this - even if the sacrifice had to be otherwise performed prior to the occurrence of the circumstantial condition, it should, after the arrival of the circumstantial condition, be performed in concordance with the circumstantial injunction".

This does not imply there is a universal invalidation of the previous way in all situations as a result of the occurrence of the circumstantial condition.

तस्मादपच्छेदन्याय: सावकाशविषय:, अद्वैतागमेन प्रत्यक्षबाधे तु न प्रत्यक्षप्रामाण्यस्यावकशोऽस्ति - Therefore, the maxim of apacCheda nyAya must be interpreted in such a way that there is scope for the validation of all scripture. However, in the case of its application where perception is overruled by advaita shruti, there would be no scope for the validity of perception at all.

The siddhikAra offers his reply.
- इति चेन्न ; If this is the argument, no.

उद्गात्रपच्छेदाभावे युगपदुभयापच्छेदे प्रतिहर्त्रपच्छेदस्य उद्गात्रपच्छेदे पाश्चात्ये च ज्योतिष्टोमद्वितीयप्रयोगे प्रतिहर्त्रपच्छेदनिमित्तसर्वस्वदक्षिणयागप्रतिपादकशास्त्रस्य सावकाशत्ववद्व्यावहारिकप्रामाण्ये प्रत्यक्षस्यापि सावकाशत्वात्, Perception too has scope for application, as an empirical means of knowledge, just like the scriptural injunction for the performance of the sacrifice of all material wealth upon the occurrence of pratihartR apacCheda has scope in certain scenarios - 1) in the absence of udgAtR apacCheda 2) when the two apacCheda-s occur simultaneously 3) when it occurs after the udgAtR apacCheda.

तत्रैकप्रयोगे विरोधवदत्रापि तात्त्विकांशे विरोधात् | If there was a requirement for both to occur in the same sacrifice (that is, if no dakshiNA was to be given in the same sacrifice where dakshiNA of all material wealth had to occur) there would be a contradiction. Similarly, here too, a contradiction with perception is only in the aspect of revealing the ultimate reality of the world (that is perception still has scope in revealing the phenomenal reality of the world).  

अत एव सगुणसप्रपञ्चश्रुत्योर्निर्गुणनिष्प्रपञ्चश्रुतिभ्यामपच्छेदन्यायेन बाध इति सुष्ठूक्तम् | Therefore, vivaraNAchArya's statement is appropriate - "it is by the maxim of apacCheda nyAya that texts describing Brahman with attributes, or reality of the world are overruled by texts postulating Brahman without attributes and unreality of the world."

तदुक्तमानन्दबोधाचार्यै: - 'तत्परत्वात्परत्वाच्च निर्दोषत्वाच्च वैदिकं | पूर्वस्य बाधकं नायं सर्प इत्यादिवाक्यवत्  ||' इति |
In this context, AnandabodhAchArya had declared - "Vedic texts overrule all prior cognitions, like the statement "this is not a snake, (it is a rope)", due to three reasons - 1) tatparatvAt - the import of shruti is in advaita, 2) paratvAt - it arises after other cognitions and 3) nirdoShatvAt, it is free from defects

The opponent objects to this:
ननु - मानान्तरविरोधे श्रुतेस्तत्परत्वमसिद्धम् , परत्वं तु प्रमानन्तरभ्रमे व्यभिचारि | Where the meaning of shruti is contradictory to other forms of cognition, it cannot be said to be its import. As regards to it possessing primacy on account of it arising after other cognitions, that rule fails in the case of an illusion arising after valid cognition.

दृश्यते च 'न क्त्वा सेडि' ति परं प्रति 'मृडमृदगुधकुषक्लिशवदवस: क्त्वे' ति पूर्वमपि बाधकम्, In PANini's ashtAdhyAyi, the sUtra न क्त्वा सेट् (1.2.18) occurs after the sUtra मृडमृदगुधकुषक्लिशवदवस: क्त्वा (1.2.7). Despite occurring first, the sUtra 1.2.7 which says क्त्वा becomes कित् for सेट् verbs like मृडमृद etc., overrules sUtra 1.2.18 which says that क्त्वा does not become कित् for सेट्  Therefore, the rule that something occurring later necessarily overrules the former does not apply.

निर्दोषत्वं त्वर्थान्तरप्रामाण्येनान्यथासिद्धम्, In relation to the veda being without defects, that can be true even if the meaning of the veda is different from the one given by the advaitin.

Therefore, none of the three reasons given for shruti overruling perception are correct.

तदुक्तं - 'तत्परत्वमसिद्धत्वात्परत्वं व्यभिचारत: | निर्दोषताऽन्यथासिद्धे: प्राबल्यम् नैव साधयेत्' - Thus it is said in the following verse - "The import of shruti being in advaita is not proven, its primacy owing to it occurring subsequently is not true universally, and it being defect-free does not prove the outcome desired by the advaitin. Therefore, shruti's superiority to perception is not proven."

The siddhikAra responds:
इति चेन्न ; प्रत्यक्षादेर्व्यावहारिकम् प्रामाण्यं, श्रुतेस्तु तात्त्विकमिति विरोधाभावेन तत्परत्वसिद्धे: | If this is the argument, no. The validity of perception is empirical, whereas shruti's validity is ultimately real. Therefore, there being no contradiction between the two, the import of shruti in advaita is certainly present.

परशब्देन च मानान्तराबाधितपरत्वं विवक्षितम्, तेन प्रमानन्तरभ्रमे न व्यभिचार:, तस्य तदुत्तरभाविमानबाधितत्वात् | By paratva, what is meant is that it is the last cognition and is unsublated by any other means of cognition. Therefore the argument that an illusion occurring after valid cognition is an exception to this rule is not relevant, because the illusion itself is sublated by another valid cognition later.

In relation to aShTAdhyAyi, the sUtra न क्त्वा सेट् is saying that the suffix क्त्वा cannot be considered कित् (kit) for a सेट् verbal root (a verb containing इट्). The sUtra मृडमृदगुधकुष क्लिशवदवस: क्त्वा is a counter-rule which says that in the case of सेट् verb roots such as मृड, मृद etc, they can be considered kit, like in the case of mRDitvA, mRditvA, etc. 

The siddhikAra says:
'न क्त्वा से'डित्यस्य तु पाठत: परत्वेऽपि स्वभावसिद्धकित्त्वस्यानेनापाकरणं विना पुनस्तत्प्रतिप्रसवार्थं 'मृडमृदे' त्यादेरप्रवृत्तेस्तादपेक्षया अर्थत: पूर्वत्वमेव;
कित् will naturally apply wherever the suffix क्त्वा is used. Without this being first denied in the case of सेट् verbs with the न क्त्वा सेट् sUtra, there would be no need to reassert (pratiprasava -  the denial of a negation) that it will specifically apply in the case of the verbal roots मृड, मृद, etc. From this, it follows that, despite न क्त्वा सेट् sUtra (1.2.17) being textually subsequent to the  मृडमृदगुधकुषक्लिशवदवस: क्त्वा (1.2.7), it logically precedes the मृडमृद sUtra.

There is a mImAmsa rule - "पाठक्रमादर्थक्रमो बलीयान्" - a logical sequence is always more powerful than a textual sequence. In this case, logical sequence takes precedence, and as the negation of negation in the मृडमृद sUtra must logically follow the negation in the न क्त्वा sUtra, it is no surprise that the मृडमृद logically overrules the न क्त्वा sUtra. 

अपवादापवादे उत्सर्गस्यैव स्थिरत्वात् अतो निर्दोषत्वमपि नान्यथासिद्धम् ; When the denial is denied, it is the second denial that will prevail. Therefore, the veda-s being defect-free does not result in dvaita / saguNatva shruti prevailing.

तात्पर्यविषय एव प्रामाण्यस्याभ्युपेयत्वात् इत्यबोधमात्रविजृम्भितमपच्छेदन्यायवैषम्याभिधानमिति || As the validity of scriptures is in things of import alone, to say that apacCheda nyAya does not apply in this case stems from a lack of understanding alone.
इत्यपच्छेदन्यायवैषम्यभङ्ग: || This concludes the chapter on the denial of inapplicability of apacCheda nyAya in relation to the world's unreality.

Post script:           

The direct meaning of the mImAmsa sUtra पौर्वापर्ये पूर्वदौर्बल्यं प्रकृतिवत् is - When two occur sequentially, the former is weaker, like in the current instance.

The sUtra does not explicitly say which two items occur sequentially. The potential pairs could be  - either the two apacCheda-s, or the two expiations covering the apacCheda-s, or the two injunctions in the veda for the two apacCheda-s, or the sentence meaning of those two injunctions, or the two cognitions arising in the mind of the sacrificer, following his perception of the two apacCheda-s and the understanding of the vedic requirement upon each apacCheda's occurrence.

As the subject matter of the sUtra is the determination of relative strength or weakness between a pair, it presupposes that the two items constituting the pair must occur in sequence and be in contradiction with each other (a discussion on relative strength is not needed if there is no contradiction). Vedic sentences cannot be said to be in sequence, so the pair referred to in the sUtra cannot be the two vedic injunctions. Therefore, nor can it be the sentence meaning of the two injunctions, or the corresponding expiations. Neither can it be the two apacCheda-s, as they do not mutually contradict each other, for both are seen to occur, sometimes even simultaneously. That being so, the consideration of the relative strength between the two pairs is most appropriate if it is between the two opposing cognitions arising in the mind of the sacrificer - whether a sacrifice with dakshiNA ought to be performed, or whether a sacrifice with no dakshiNA ought to be performed in the current prayoga.

The nyAyAmRtakAra on the other hand, considers that the pair being referred to in the sUtra to be the two injunctions (or more generally, pramANa-s), and takes it as the sublation of the former pramANa, by the latter pramANa. However, as the validity of any sentence in the veda cannot be denied, he postulates that the scope of apacCheda nyAya needs to necessarily be within the purview of the non-sublatability of the prior pramANa, and claims that it is on these grounds that the application of apacCheda nyAya is deemed inadmissible in a situation where perception is completely overruled. 

This however, is not the intention of the pUrva mImAmsa sUtra, or for that matter, the application of apacCheda nyAya by VAchaspati MiSra and other advaitin-s in the context of advaita shruti / mithyAtva inference. It is not the validity of the prior means of knowledge that is being denied by the maxim, rather it is the relative weakness of the prior comprehension in the mind of the subject in comparison to the latter comprehension.  

When the first apacCheda occurs, the sacrificer becomes cognisant of the need for a particular course of expiation. When a different apacCheda occurs later, the sacrificer dismisses his prior thinking as no longer applicable, and then thinks that the second expiation is appropriate. Thus the relative prAbalya / daurbalya, strength and weakness is not of the means of knowledge, but the validity of the cognition - whether "no dakshiNA should be given", or whether "everything ought to be given as dakshiNA" in a particular prayoga.

Secondly, the nyAyAmRtakAra had argued that there is no contradiction for there to be a test of relative strength and weakness. In one instance of the sacrifice, dakshiNA is not given, and in a subsequent instance, everything is given. He had compared it to the case of the raw berry changing colour when it ripens. To say that the green berry has become red, does not invalidate that it was red in the past. This was his contention.

This is an incorrect comparison because the contradiction being referred to is within one instance of the sacrifice - should dakshiNA be given now or not, and if so, what should be given? The sacrifice that was without dakshiNA did not become the sacrifice with dakshiNA, like in the instance of the green berry turning red. A prayoga without dakshiNA is different from the next prayoga with dakshiNA, whereas a berry which is green is not different from the berry which is red. The berry cannot be green and red at the same time - that would be a contradiction. Neither can the prayoga be both with and without dakshiNA  simultaneously.

Thus, it is the validity of two contradicting cognitions occurring one after the other that is the subject matter of apacCheda nyAya, not the validity of contradicting pramANA-s. A question may be asked here -  isn't the validity of cognition ultimately a test of the validity of the pramANa that gave rise to it? Not necessarily. When shruti says "if udgAtR apacCheda occurs, perform the sacrifice with no dakshiNA", what is really meant is that if that happens to be the final apacCheda, do so. The same applies in the case of the injunction governing pratihartR apacCheda. As one cannot predict the future to say whether an apacCheda that has occurred is the final one or not, one notionally assumes that it is the last one - until the earlier of the completion of the sacrifice, or the occurrence of another apacCheda. That notion of finality and the conclusion that "this is the expiation that needs to be performed" is the one that is disproved upon another apacCheda. This ignorance of whether the course of action that one is pursuing is the correct one or not, is that which is the cause for the future sublatability of the underlying cognition that one had assumed to be true.

The same holds good for the perception of the world's reality. Until one is convinced of the import of shruti lying in advaita, one continues to hold on to a notion of reality assumed as a result of perception. Perception is not incorrect, the notion that perception reveals ultimate reality is incorrect. When one understands that the import of scripture is in non-duality, the notion of reality arising from perception is cast aside, like in the case of apacCheda nyAya.