by Babu C. D | 2018 | 44,340 words
This thesis is called: The validity of Anumana (inference) in Nyaya system. It tries to establish the validity of Anumana through citing its application either consciously or unconsciously in every sphere of human life. Anumana in Nyaya system is the knowledge of any object not by direct observation but by means of the knowledge of a liṅga or sign ...
The Carvakas accept Perception as the only means of valid knowledge. The validity of other means of knowledge like Anumana, Shabda etc., is rejected by them. In the case of Perception they speak about two types of it (i) external and (ii) internal. External perception arises due to the contact of the five sense organs with their concerned objects. Internal perception depends upon the external existence of objects and organs. It will not keep off the external sense organs. According to them the perceptible world is the only reality.
The validity of Inference is accepted by all the Indian philosophers except Carvakas. To understand the character of Inference one has to consider the object to be really inferred; the real cause of inferential knowledge;classification of Inference; the number of inferential components and the like. There may be great divergence of opinion but almost all philosophers unanimously accept that the inference (Anumana) is an independent pramana.
Buddhists have admitted and taken effort to prove the validity of inference when questioned. Their attitude towards Inference as a source of valid knowledge is significantly different from that of other schools subscribing to the same position.
As against the Nyaya tenet of pramana samplava, more than one pramana may reveal the same object. The Buddhists uphold the tenet of pramana vyavastha, which states that each of the two sources of valid knowledge reveals the quite specific type of object. An object of knowledge, according to them, must be either a svalakshana or a samanyalakshana but none other than these two. If it is a svalakshana, it would be an object of Perception and if it is a samanyalakshana, it would be an object of Inference. Just as Perception cannot cognize a samanyalakshana, an Inference cannot cognize a svalakshana 
Most of the modern scholars who appreciate the representation of the Carvaka view point do not find any ground for examining critically the tenability of such a position. Hiranya comments that it is commonly assumed by the critics that the Carvakas denounced reasoning totally as a pramana; but to judge from the reference to it in one Nyaya treatise, they seem to have rejected only such reasoning as was ordinarily thought sufficient by others for establishing the existence of god, of a future life etc. Such discrimination in using reason alters the whole complexions of the Carvakas view. But this is only a stray hint of truth. What is needed generally is a caricature. 
Chattopadhayaya criticized the classification of the Carvaka school into two; (i) the susiksitas and (ii) the dhurtas, which got a revelation from a sarcastic remark of Jayanta Bhatta. The distinction between the two as alleged is that the former believed in the validity of Inference while the latter did not.
Arthashastra classifies various branches of vidhya (learning). Kautlya says that the branch of learning known as Anvisiki comprises Sankhya yoga and Lokayata. In the descriptive passage following the classification, which seeks to establish logically the usefulness of Anvisiki, Kautilya has given a hint, though very implicitly, about the special characteristic of Anvishiki. For a clear definition of Anvishiki based upon the etymology of the word, Vatsyayana, the author of Nyayabhashya should be referred to. In the commentary on the first sutra he remarks that an Inference which is not contradicted by perception and scripture is called anviksha, that is the knowing over again of that which is already known (ikshita) by perception and scripture. This branch of knowledge is called Anvikshiki or Nyayavidya or Nyayashastra because it developed on the basis of that. 
Vatsyayana recognizes the essential characteristics of Anvikshiki that depend upon Inference or reasoning. But the Sankhya has no hesitation to admit the validity of Inference as proved by the system. The major principles of Sankhya as priakriti and purusha cannot be brought to the notice of the world unless they seek the aid of the Inference.
Considering all these facts, Kautilya tends to open a new school of study called lokayata as a branch of anvisiki not forsaking Inference. Udayana argues that if the Carvaka do not admit Inference, they cannot admit perception either, for in that case the existence of the sense organs would remain unproved due to their invisibility. Further, if a Carvaka leaves the house for market he will begin to lament for his wife, children and others as for him those who are not seen do not exist. He denies the validity of Inference which would have come into help otherwise.
Bhartrihari, in his Vakyapadiya, through many a number of examples try to prove the compatibility of Inference to yield true knowledge about the nature of an object. In his remarks, ‘one who tries to arm himself to fight with others on the basis of inference will resemble a blind man who with the help of the tactual sense alone tries to proceed in an uneven path and stumbles constantly is a notable one.’ Some of these verses have been quoted along with others, so as to show how the Carvaka efforts go in vain while they oppose Inference without proper reasoning and leaving many of the authors like Jayanta Bhatta, Santa Rakshita and Vadidevasuri without any reference.
“Bhatrihari recognizes the usefulness of inference and reasoning in everyday life. He points out that even perception would be incomplete without the help of inference. Though the whole of a thing is not visible one can infer the rest with the available parts.”
In ordinary life, the validity of Inference cannot be estimated so easily. Vriitti, the commentary of Rishabhadeva, also depicts the above view purely through common instances which occur in day to day life. Bhartrihari’s attack against Inference shows how deeply he is abided to its manifold encumbrances by which many a type of their already perceived turn to be untrue owing to its hair splitting analysis. Therefore, Bhartrihari ultimately recognizes the utility of such reasoning ‘as is not in contradiction with implication of the scripture, a position subscribed to it by Nyaya also. At the same time, he was alert in keeping his ideas free from any type of deformation, since he moulded them on the basis of the sacred scriptures. He could not tolerate any of it being uprooted owing to its incapability to withstand the long way proclamation of a new trend that overshadowed any minute type of logical affirmation that came on its way through the label of a source of knowledge.
Footnotes and references:
Hiranya, Outlines of Indian Philosophy, p.188
Vatsyayana Nyayabindu, 1.1.1
Vakyapatiya, chapter 1, verse 30-42
Indian logic in its sources validity of Pramana, p.31
Bhatrihari, A study of the vakyapatiya in the light of ancient commentaries, p.84
Vakyapatiya, Chapter 1, verse 127