Nyāya Sūtras 78.8

78.8

vṛkṣāyodakam āsiñcatīti āsicyamānenodakena vṛkṣam abhipraitīti sampradānam/ vṛkṣāt parṇaṃ patatīti ``dhruvam apāye 'pādānam'' ity apādānam/ vṛkṣe vayāṃsi santīti ``ādhāro 'dhikaraṇam'' ity adhikaraṇam/ evam ca sati na dravyamātraṃ kārakam, na kriyāmātram/ kiṃ tarhi? kriyāsādhanaṃ kriyāviśeṣayuktaṃ kārakam/ yat kriyāsādhanaṃ svatantram sa kartā, na dravyamātraṃ na kriyāmātram/ kriyayā vyāptum iṣyamāṇatamaṃ karma,

In 'he pours water for the tree', it is the recipient because he intends the tree by means of the water being poured. In 'a leaf falls from the tree', it is the point of departure according to 'that which is fixed in moving away is the point of departure'. In 'birds are in the tree', it is the locus according to 'the substrate is the locus'. And this being so, a mere substance is not a grammatical role, nor is a mere action. What then? A means of action endowed with a specific action is a grammatical role. That means of action which is independent is the agent, not a mere substance, not a mere action. What is most desired to be reached by an action is the direct object,