After a verb ending in the affix ṇi (causal) the ātmanepada is used, provided that when the object in the non-ṇi or non-causal sense becomes the agent in the causal; and when it does not mean 'to remember with regret', even when the fruit of the action does not accrue to the agent.,
The causatives (णिच्) are conjugated in the atmanepadi, when they are used in the passive voice, that is to say when a word which was an objective case in the ordinary verb becomes nominative case in the causative; and the nominative case of the ordinary verbs becomes objective case in the causative. In short when causatives are used in the passive voice, they are atmanepadi. This round-about phraseology has been employed, because the base of the active and the passive causatives do not differ in form; as आरोहते हस्तिपकान् हस्ती.
The phrase 'णेः (after the causatives)' of this sutra governs the four succeeding sutras and is understood in them. The sutra consists of the following words:- णेः 'after the causative;' अणौ 'in the non-causative;' यत् 'what;' कर्म 'object;' णौ 'in the causative;' चेत् 'if;' सः 'that;' कर्ता 'nominative;' अनाध्यान 'except to remember.'
In general, by sutra 1.3.74, the causative verbs take the terminations of the atmanepada, when the fruit of the action accrues to the agent. The present sutra applies to the case where fruit of the action does not accrue to the agent.
After the verbs that take the affix णिच्, the terminations are those of the atmanepada. How? When that which was the object when the primitive verb was used non-causatively, becomes also the object when the derivative verb is used causatively; and even that object becomes also the agent as well. There is exception, however, in the case when the verb means to 'remember with regret.' As आरोहन्ति हस्तिनं हस्तिपकाः 'the elephant-keepers mount the elephant.' Let us paraphrase this sentence by transforming the primitive non-causative verb आरोहन्ति into a causative form. The sentence then will be, आरोहयते हस्ती स्वयमेव 'the elephant makes itself to be mounted.' Similarly उपसिंचन्ति हस्तिनं हस्तिपकाः 'the elephant-keepers sprinkle the elephant'; and उपसेचयते हस्ती स्वयमेव 'the elephant makes itself to be sprinkled;' पश्यन्ति भृत्या राजानम् 'the attendants see the king'; and दर्शयते राजा स्वयमेव 'the king makes himself to be seen.'
Why do we say 'after the causatives?' Because the rule of this sutra, will not apply, if the verb though conveying the sense of a causal verb, is, however, not formed by the affix णिच्; as आरोहन्ति हस्तिनं हस्तिपकाः 'the elephant-keepers mount the elephant;' and आरोहयमाणो हस्ती साध्वारोहति 'the elephant that is being mounted, mounts gracefully'. Here the terminations are of the parasmaipada in the second case also.
Why do we say 'in the non-causative non-ni'? For this rule will not apply when the primitive verb itself is formed by the affix णिच्; such are the roots of the tenth class or churadi in which the nich is added in the self-descriptive sense, and not for a causative purpose. Thus the root गण belongs to churadi class; whose causative and primitive forms are the same. As गणयति गणं गोपालकः 'the cowherd counts the herd;' and the causative form is गणयति गणः स्वयमेव 'the herd makes itself to be counted.' The terminations in both cases are those of the parasmaipada.
Why do we say 'when the object (karma) becomes the agent?' Because the rule will not apply, when any other karaka or case, than the karma or object, of the primitive verb becomes the agent in the causative. Thus लुनाति दात्रेण 'he cuts with the scythe,' लावयति दात्रं स्वयमेव 'the scythe is made to cut of itself.' Here the word datra was the instrument of the primitive verb which became agent in the causative, and therefore in the causative the terminations are of the parasmaipada only.
Why do we say 'if in the causative' in the sutra? It is for the purpose of indicating that the verb must be one and the same, both in the primary sentence and the causative sentence. Therefore the rule does not apply here where the causative verb सेचयति in the second sentence was not used in the first sentence; आरोहन्ति हस्तिनं हस्तिपकाः 'the elephant-keepers mount the elephant;' and आरोहयमाणो हस्तीभीतान् सेचयति मूत्रेण 'the elephant that is being caused to mount is made to sprinkle with urine the frightened men'.
The word सः 'that' is employed in the aphorism to show that the objects in both sentences must be the same and not different. Therefore in the following example where the objects are different, the terminations of parasmaipada are only used. आरोहन्ति हस्तिनं हस्तिपकाः 'the elephant-keepers mount the elephant'; and आरोहयमाणो हस्ती स्थलमारोहयति मनुष्यान् 'the elephant, that is being caused to mount, makes men mount on the land.'
Why do we use the word karta (agent) in the sutra ? If the former object is not the agent in the second case, the terminations of the parasmaipada only would be used. As आरोहन्ति हस्तिनं हस्तिपकाः 'the elephant-keepers mount the elephant;' and तानारोहयति महामात्रः 'the elephant-driver makes it to mount.'
Why do we say 'except when meaning to remember with tenderness?' Observe, स्मरति वनगुल्मस्य कोकिलः 'the dove remembers, with regret, the forest tree;' and स्मरयत्वेनं वनगुल्मः स्वयमेव 'the forest tree is made to be remembered of itself.',