Prajñākaragupta on the Two Truths and Argumentation

How is it possible to say that truth can be of one kind at the conventional level and totally different in the ultimate plane? As Matilal ( 1971 , p. 154) points out, Kumārila (ca. 600–650), a Mīmāṃsaka philosopher, claims that the Buddhist doctrine of two truths is “a kind of philosophical ‘double-talk’.” It is Prajñākaragupta (ca. 750–810), a Buddhist logician, who tries to give a direct answer to this question posed by Kumārila from the Buddhist side. He argues that even a Mīmāṃsaka cannot demonstrate the validity ( prāmāṇya ) of the Veda without accepting two truth levels. His point is this. Consider the proposition to be proved: the Veda is valid. If the Veda is already known as valid, then it is useless to prove this proposition. But if it is already known as invalid, then it is impossible to prove this proposition. Therefore in the argument to prove the proposition, the Veda is not to be regarded either as valid or as invalid. This means that at the first stage of the argument one has the concept of the Veda as neutral in validity. However, as soon as one acquires the knowledge of the Veda as valid through the argument, one has to repudiate such a conception of the Veda. The acceptance of the Veda as neutral in validity is to the acceptance of the Veda as valid as the conventional truth is to the ultimate truth