Why do Viśiṣṭādvaita Vedāntin authors care for a Mīmāṃsā-related text which Mīmāṃsākas ignore, and which only seems to deal with minor ritual topics?

The Saṅkarṣakāṇḍa (henceforth SK) is a set of 465 sūtras divided into four books (adhyāya), within which are 16 pādas and 386 adhikaraṇas (Verpoorten 1987, p. 6). As for its content, Verpoorten writes that “The SK deals with sundry ritual problems, such as a subsidiary of the agniṣṭoma called anuvaṣaṭkārayāga, the sacrificial post (yūpa), the avadāna or cutting of the oblations for each deity, the varaṇa or appointment of the priests, and lastly, various kinds of mantra” (Verpoorten 1987, p. 6).

Verpoorten notes as indirect support of the date and Mīmāṃsā-status of the SK an inscription of “Anur (Chingleput district, Tamil Nadu) of 999 A.D.” where the single śāstra made of Pūrva and Uttara Mīmāṃsā is said to consist of 20 books, i.e., presumably, the 12 of the Pūrva Mīmāṃsā Sūtra (henceforth PMS), the 4 of the Brahma Sūtra (henceforth BS) and the 4 of the SK. As for manuscript evidence, “manuscripts have been discovered only lately”. A note specifies that manuscript evidence seems also to point to South India, since manuscripts are “[m]ainly from South India: Malabar, Trivandrum, Madras; all of them seem to proceed from the same origin” (Verpoorten 1987, pp. 6–7). Among contemporary scholars, opinions diverge, regarding the authorship of the SK (in favour of its attribution to the same author of the PMS, see Ramasvami Sastri 1933) and its antiquity (see Sandal who claims that it is “spurious” and late, whereas the above-mentioned passages by Verpoorten seem to be more open towards its possible antiquity).

As for secondary testimonies, Śabara seemingly refers to it in his commentary ad PMS 10.4.32, where he adds that a certain topic will be said in the Saṅkaṛṣa (saṅkarṣe vakṣyate). The Ṭīppaṇī (a gloss to the PMS  in the form of footnotes added by Ganeśaśāstrī Jośī) explains: “The meaning is that it is will be said in the Saṅkarṣakāṇḍa 14.4.21” (a° 14 pā° 4, sū° 21 ity atra saṃkarṣakāṇḍe vakṣyata ity arthaḥ). A similar passage is found in Śābarabhāṣya (henceforth ŚBh) ad PMS 12.2.11, where Śabara says that “it will be said in the Saṃkarṣa” (saṅkarṣe vakṣyate). Nothing is added in the Ṭīppaṇī. The usage of a future tense seems to suggest the sequence PMS-SK, although it is by no means clear that saṅkarṣe refers to the title of a work. I did not find any other case of iti+title of a work+vakṣyate in the ŚBh, although vakṣyate is frequently used to refer to later passages of the PMS and/or of the corresponding ŚBh. Kumārila does not comment upon these references, nor could I find any other reference to the SK in authors prior to the 9th c. apart from an interesting passage by Śabara, in his commentary on BS 3.3.43, where he says: “Therefore it has been said in the Saṅkarṣa: ‘Verily the deities are many, because they are distinctly known’ ” (tad uktaṃ saṃkarṣe nānā vā devatā pṛthagjñānāt iti). Here the sūtra referred to seems to be clear, namely SK 2.2.36, nānā vā devatā, pṛthaktvāt. This is a key element, as we will see.

Departing from the 9th c., Veṅkaṭanātha (alias Vedānta Deśika) and other authors and evidences  (as far as I know, all from South India) situate the SK after the PMS and before the BS and hold different views re. its authorship.
The first commentary we possess upon the SK is that of Devasvāmin (11th c.), who could be the same author who commented upon the Āśvalāyana Śrauta Sūtra. This hypothesis could be reinforced by the fact that, as acknowledged also by the ones who support its authenticity (see a few lines below), the SK “is more in the nature of the Kalpasūtras”, since, unlike the PMS, it “has not got any separate principle to enunciate and, therefore, is a miscellaneous supplement” (Ramasvami Sastri 1933, p. 297). A further commentary, the Bhāṭṭacandrikā by Bhāskara or Bhāskararāya explicitly states that the text lacks the connection (saṅgati) among adhikaraṇas. Appayya Dīkṣita describes the SK as follows: “After having composed the PMS for the sake of investigating on dharma, since there he had not defined in sūtras some rules, for the sake of collecting them, Jaimini, the best of the great ṛṣis, composed the SK, which is a supplement to the PMS”. Thus, all same to agree on the less systematic nature of the SK, which might have been an appendix of the PMS composed to account for further minor issues. Why did it become so central for the Vṛttikāra, Rāmānuja and Veṅkaṭanātha? Why did they decide to explicitly focus on it?

The answer probably lies in the way they refer to it: as we have seen, the SK is mainly a sort of Kalpasūtra discussing trivial ritual matters. This cannot have been of particular interest for the Vṛttikāra, Rāmānuja and Veṅkaṭanātha (whose Seśvaramīmāṃsā never enters into ritual details). By contrast, they present the SK as introducing the topic of the deity (devatā). This is also the context in which Śaṅkara inserts his reference to the SK, so that its connection with the topic appears to predate Rāmānuja and Veṅkaṭanātha. In this way, the SK becomes a way to make theism be present in the unitary śāstra since its very beginning.

However, this leaves still many questions open, such as: In which milieu has the specific connection of SK and theism been crafted? In which context and when has the SK been composed? What was the Pūrva Mīmāṃsā stance on it?
On Veṅkaṭanātha, follow the links from this post. On the Vṛttikāra, Veṅkaṭanātha’s agenda and the SK in it, see also this presentation of mine.