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NYAYA THEORY OF KNOWLEDGE
and non-syllogistic, pure and mixed. Having regard to their purposes, or the nature of vyāpti, or the nature of the induction on which it is based, inferences are classified into svārtha and parārtha, or into pūrvavat, sesavat and sāmânyatodȚşta, or into kevalānvayi, kevala-vyatireki and anvaya-vyatireki. The fallacies of inference are all material fallacies which affect the truth of the propositions involved in inference. They ultimately arise out of a fallacious reason or middle term. There are six kinds of fallacious middle terms which violate one or other of the conditions of a valid middle term. A logically valid inference must be free from all kinds of fallacies.
Comparison is the source of our knowledge of the denotation of a word on the basis of a given description of the objects denoted by it. Thus & man may be told : “A gavaya is an animal resembling the cow" If, on subyequently seeing a gavaya, he is able to give its name, we are to say that he understands the denotation of the word through comparison. Comparison is of different kinds, according to tbe different terms in which the description may be given. It is true that comparison involves an element of perception and of testimony. The description comes to us as the statement of some authority and, as such, is a kind of verbal testimony. So also, we know by perception that certain objects possess the characters mentioned in the given description. Sull comparison cannot be reduced to perception and testimony, because these will not explain the application of the name to the relevant objects, which is the essence of comparison. Nor can we explam it by inference, for when we know the denotation of a word from a given description, we do not reason syllogistically, but simply compare certain objects with a given description. To understand the denotation of a word in this way requires a selective activity of the mind, which is different from perception, inference and testimony.
