________________
TEST OF TRUTH AND ERROR
95 knowledge be self-evident, there is nothing to prevent the prinary knowledge from having self-evident validity. Further, it will involve a surrender of the Naiyāyıka posltion that the validity of all knowledge is constituted and ascertained by external conditions. Hence it seems that on the Nyāya theory of validity, the process of the verification of knowledge will go on as an infinite chain of arguments, in which every link will hang on the next, but the last link is never to be found (anūdiparamparā).'
To this the Naiyāyıkas reply that the validit of a knowledge must be known hy extrinsic conditions wherever it is necessary to know it at all But it is not always necessary to ascertain the validity of a knowledge. It becomes necessary wben any doubt as to its validity actually arises. Thus when we have the visual perception of water and have any doubt about its validity, we do of course ascertain it by inference from some successful activity, 1. e. by touching or drinking the water. But the validity of the verilying experience requires no further examination or proof. There being no doubt about its validity we do not feel any necessity to prove or ascertain it. Hence the tactual perception of water validates the visual perception of it even when there is no ascertainment of its own validity. When however we have any doubt about the validity of the tactual perception, we must establish it by other external conditions, such as the corroborating testimony of different persons. Thus it follows that to know the validity of a knowledge by external grounds, it is not necessary to know the validity of those grounds so long as they stand undoubted and uncontradicted (samśayābhāva) If any one still doubts that the validating ground may itself be valid or not, then we have an unmeaning motiveless doubt which has no place in logic.?
1 TC, I, pp 276-77, NM, pp. 162 f. 2 NM, p 173, TC, 1, pp 277-79, 282f
