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NYAYA THEORY OF KNOWLEDGE
not be the basis of effective actions. The Naiyāyikas, therefore, conclude that the truth of knowledge is not selfevident in it, but is evidenced or known by inference from successful activity. By successful activity, they mean the volitional experiences (arthakriyājñāna) of the expected object (phalajñāna). The perception of water in a certain place is known to be true when by acting on that perception we meet with the expected water. Contrariwise, a knowledge is known to be invalıd, when it is contradicted by subsequent volitional experiences (pravrttuisamvāda). That is, the invalidity of knowledge is mferred from the failure of the practical activities based on it The perception of silver in a shell is known to be illusory because the act of picking up does not give the expected silver. Hence pravșttisāmarthya means that the object as cognised is found present when acted upon by us, 2.e. it is given to volitional experience just as it was given to the corresponding cognitive experience.'
In the case of the knowledge of familiar objects (abhyāsadaśājñāna), we do rot require the test of successful activity or conative satisfaction (pravrttisamarthya). In this case it may seem at first sight that the validity or invalidity of knowledge is self-evident (svatah). A habitual experience is known to be valid or invalid even before we proceed to act upon it and see if it leads to the expected object or not. It would therefore seem that the validity or invalidity of habitual experience need not be known by any inference and, as such, is self-evident. But here the Naiyāyikas point out that it is a contradiction to say that the truth of the familiar is self-evident. The knowledge of the valıdıty of familiar knowledge is conditioned by the conditions of its familiarity. The familiarity of knowledge means its similarity to previous
| NM, pp 171-72.
