Ānvīkṣikī means argument, reason, judgement. Since in Rāmāyaṇa and Mahābhārata, Ānvikṣikī is mentioned in the same breath with hetuvidya, tarkavidya, nāstikata and vedanindā, there is doubt about its real meaning.
In a śloka of Śāntiparva in Mahābhārata, Indra, in the shape of a jackal, relates the reasons for his birth as a jackal, saying that — “I was a scholar, a causalist and a condemner of Veda. Great was my fondness of Ānvikṣikī and argument. As a result, in a whole assembley of scholars, I used to talk like a causalist. At that time I also used to say harsh words to the Brāhmaṇa and pointed out their faults in speech. I raised doubt about everything, and due to that atheism, I have been transformed into a jackal.
The use of Ānvkṣikī along with hetuvidya, tarkavidya, nāstikata and vedanindā in Śāntiparva of Mahābhārata has created a new significnce for the term. In India, those ho have marshalled their arms against āstikatā, are the ones who mostly relied on reasoning and argument. This is further proved in the other mahākāvya Rāmāyaṇa as well. When Bharata came to the forset in order to convince Rāmacandra to return, Rāma asked him several questions about the well-being of Ayodhya. Among these questions, Rāmacandra asked Bharata — You don’t serve the lokāyatika Cārvāka or the dry, argumentative Brahmaṇa, isn’t it so? They are only interested in proving the futilitydisregard the paraloka and the service towards paraloka. Though being immature like boys, they consider themselves to be wise. Moreover, they neglect our chief scripture Veda, and make worthless arguments following the path of Ānvikṣikī.
Scholars have sought to determine the way how Manu has described the term Ānvīkṣikī in noun-adjective relationship with Ātmavidyā or Self knowledge, and how that term came to be used as an analogous term for logic and discourse. They say– in the time of Upaniṣad and Brahmasūtra etc., while discussing Ātmatatva, the term Ānvīkṣikī has been used in the sense of self-knowledge, but afterwards, before the time of Kauṭilya, it has been come to be used as analogous with discourse and logic. Especially it gets corroborated when Vātsayana, sūtra-composer of Nyāyaśāstra, has distinguished between Ātmavidyā and Ānvīkṣikī. Vātsāyāyana has written– the thee treaties composed by Kauṭilya–that is, daṇḍanīti, and ānvikṣikī– these four epistemological paths have been imparted for favouring all the creatures. Among these four paths, ānvīkṣikī is the fourth epistemological path, and this is also ̍Nyāya-vidyā̍. If a separate path for Ānvīkṣikī through argument and discourse did come come into shape, it would have simply meant ̍Ātmavidyā̍ or ̍Adhyātmavidyā̍, as it had been in Upaniṣad(s).
Especially according to the statement of Nyāyabhāṣya, Pandit Satishchandra Vidyabhusan has commented that the the use of the term Ānvīkṣikī came to be used in the sense of logical discourse since the 550 BCE, as Medhātithi Gautama has identified the signoficance of logical argument in Ānvīkṣikī– once, by directly using the term, and another time, saying that logical argumentation is the only way to reach a decicise conclusion. Since Gautama has insisted in this, Satishchandra Vidyabhusan has remarked that, chiefly from this time, Ānvīkṣikī came to be used in the sense of logical argumentation, and at the time of Kauṭilya, in Rāmāyaṇa and Mahābhārata, it came to be considered as a separate philosophical path.
When in the writing of early scholars, when Ānvīkṣikī had been used in the sense of logical discourse, or whenwe see that Kauṭilya using ̍Sāṃkhya̍, ̍Yoga̍, ̍Lokāyata as similar to this term, Sāṃkhya or Yogā, had not been yet considered as separate philosophical paths at that time. These have been understood as analogous terms for logical discourse and research, what we call ̍methodology̍ in English. Some people have called it ̍enumerative principle̍.
In fact, Ānvīkṣikī is not any such general concept that can be used as analogous term for several philosophical paths in the Indian tradition. Ānvīkṣikī can be compared to such an idea, in which there is not only philosophy, but there is search for any thought.
Like a flame, ānvīkṣīkī throw light on all subjects, and acts as a means of any way of karma, and as the shelter or base of any thought–
pradīpaḥ sarvaśāstrānā upāyaḥ sarvakarmaṇām
āśrayaḥ sarvadharmāṇām śaśvad ānvīkṣīkī matā.
When Kauṭilya mentioned Sāṃkhya, Yoga, Lokāyata etc. as examples for ānvīkṣīkī, he wanted to mean that in his time, these ways were mostly used as means or methodology for theoretical searching. This statement of Kauṭilya has been supported by Vātsāyana̍s commentary on Nyāyabhāṣya, while analysing the term ānvīkṣīkī. The commentator of Nyāya has written, The re-examination or proof-oriented examinationof subjects that have already been conceptualised through senses and āgama, is called ānvīkṣīkī.
Exactly at this point, the meaning of the term sankhyā, in the annotation made by Vṛhspati Rāyamukuṭa, the commentator of Amarakoṣa. In the 15th century, in the commentary called Padacandrikā, after analysing terms like ̍carchā̍, ̍sankhyā̍, ̍vicāraṇā, in conclusion writes that these three terms are used in case of determining the meaning with the help of proof. Other scholars, however, use these three terms in the sense of logical discourse or vimarśa.