Atideshavakya is a statement of analogy by an authority. The Nyayayikas accept upamana (comparison) as an independent and irreducible Pramana (source of valid knowledge). Upamana, according to the Naiyayikas, involves atidesavakya, sadrishyadhi and vakyarthasmriti. Atideshavakya means an authoritative statement of analogy. We acquire the knowledge of an object previously not known on the basis of atideshavakya.
Atideshavakya is an authoritative statement showing the
relation between a word and the object it denotes. According to early
Naiyayikas, the description of an unfamiliar object is suggested in terms of
its similarity with some familiar object of experience.
To illustrate, when we are informed by an authoritative
source that ‘gavaya’ or ‘wild ox’ is an animal resembling the ‘cow’, we come to
know the denotation of the world gavaya, though we have not yet seen the animal
before.
Upamana thus consists in relating the object, not known
before, with the word denoting it, on the basis of atideshavakya, which shows
the resemblance between the unfamiliar and the familiar object.
For later Naiyayikas, however, the description of the
unknown object denoted by a word may also be suggested in terms of its
dissimilarity to certain well known objects or in terms of its peculiar
property. For instance, when we are informed by an authoritative source that ‘like
the cow, horses have no cloven hoofs’ or the ‘giraffe is a long-necked animal
feeding on branches’, we come to know the animal denoted by the word even if we
have not seen the animal earlier.