Dharmakīrti states in Pramāṇavārttika 2.1 that pramāṇa (valid cognition) is avisaṃvādi-jñāna (reliable cognition) and that avisaṃvādana (reliability) means arthakriyāsthiti (the confirmation of causal efficiency). Whereas Dharmottara regards pramāṇa as avisaṃvādaka-jñāna, he explains avisaṃvādakatva, which is equal in meaning to avisaṃvādana, as pravṛttiviṣayapradarśakatva (the indication of the object of activity), and does not accept arthakriyāsthiti. What is his reason for doing so?
Dharmottara regards arthakriyā as the obtaining or the shunning of objects in the case of inference (Nyāyabinduṭīkā on Nyāyabindu 1.1). He clarifies that pramāṇa allows human beings to understand an external object but cannot force them to take action (Nyāyabinduṭīkā on Nyāyabindu 1.1). As a pramāṇa, inference cannot always lead to arthakriyā as described above, because there is no assurance that one must take action after making an inference. Thus, the concept of arthakriyāshiti formulated by Dharmakīrti will present the problem that inference as such cannot be regarded as pramāṇa. Dharmottara solves this issue by introducing the concept of pravṛttiviṣayapradarśakatva: The status of being pramāṇa is guaranteed to inference as long as it serves to show the object of activity (Nyāyabinduṭīkā on Nyāyabindu 1.1).
