Rule. The one who prompts (prayojaka) the agent is given the name hetu. He is also given the name kartṛ, "agent". Bhaṭṭoji's gloss: "what prompts the agent receives the designation hetu and also the designation kartṛ".
The word tat, "that", points back to the agent of the preceding sūtra, svatantraḥ kartā (SK 559). Bhaṭṭoji's commentators agree on this. The one prompted is called the prayojya, "the one to be prompted".
Example.
"Yajñadatta makes Devadatta cook": pac + ṇic.
→ Devadatta does the cooking; he is the agent by SK 559
→ Yajñadatta sets that agent going; by this rule he is hetu
→ by this rule he is also kartṛ.
In bhāvayati likewise: the one who impels is hetu and kartṛ; the one who becomes is the prompted agent.
Applies when / blocked by. Why two names? One of Bhaṭṭoji's commentators explains. Only Devadatta is the locus of the cooking, so without this rule the prompter would not be kartṛ. And without the name hetu, his being a cause would be credited to the prompted agent.
The other commentator gives each name its use. The name hetu is used in SK 2594 and SK 2595 (hetubhaye, "when the fear comes from the hetu"). The name kartṛ lets the lakāra express the prompter, by SK 2152 (laḥ karmaṇi ca…).
How does the word ca add the second name? One commentator says ca gathers in the name kartṛ from SK 559. The other says ca sets aside the heading by which a thing takes only one name. Both reach the same double name.
Watch out. There are now two agents in the sentence. The prompted one is the agent of the root's own action. The prompter, being kartṛ too, is the one the lakāra expresses: in bhāvayati the ending -ti speaks of him.
What prompts the agent (kartuḥ prayojakaḥ) receives the designation hetu and also the designation kartṛ.
- commentary BM: the word tat refers back to the kartṛ taken up in the preceding sūtra svatantraḥ kartā; tatprayojaka = the one who sets that agent going (pravartayitā); the ca gathers (samuccinoti) the designation kartṛ from the preceding sūtra. The kartṛ designation is taught because in 'Yajñadatta impels Devadatta, who cooks' only Devadatta is the locus of the activity that is the meaning of pac, so the prompter would not be kartṛ; the hetu designation is taught because the prompter's being a cause would otherwise be accounted for by the prompted agent. Followed: 'of that [agent]' and the bracketed kartṛ, added by the ca (samuccaya; BM speaks of gathering, not of anuvṛtti).
- commentary TB (sk.2575.t1, re-filed from the tail of sk.2574.t1 on 2026-10-05): tat refers to the kartṛ of svatantraḥ kartā; the prayojaka is the one who impels (preraka), whose activity is conducive to that [agent's] activity; the ca sets aside the governing rule that a thing takes only one designation (ekasaṃjñādhikāra), hence 'hetusaṃjñaḥ kartṛsaṃjñaś ca'. Purpose of hetu: the prompter is spoken of as hetu in bhīsmyor hetubhaye (SK 2594) and bhiyo hetubhaye ṣuk (SK 2595); purpose of kartṛ: the lakāras etc. by laḥ karmaṇi ca bhāve ca… (SK 2152) when the prompter is to be expressed. Agrees with BM on tat; followed. TB's account of the ca (setting aside the ekasaṃjñā rule) differs in emphasis from BM's (gathering the kartṛ designation); both yield the double designation, which is all the English states.
- textual Collation (batch06), NSP p. 428 (scan page-0438): the print heads this section 'tiṅante ṇyantaprakriyā 51'; our prakaraṇa name tiṅantaṇicprakaraṇam and number 54 follow the Wikisource style and our own numbering. Informational; the kaumudī text of this unit agrees with the print.