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LATER BUDDHISTIC SCHOOLS
201 that does so. He would not believe for instance in the proposition 'All animals with cloven hoofs have horns,' although the concomitance of the two, so far as our knowledge goes, is invariable; for its truth cannot, as in the cases mentioned, be referred back to any general principle whose validity is unquestioned. There is no clinching argument to meet the question 'Why should the cloven hoof be associated with horns?' and any doubt that may be entertained about the matter will, therefore, remain unremoved. In other words, the Buddhist admits the principle of the uniformity of nature only in the two spheres of causal sequence and necessary co-existence. By thus restricting the scope of vyāpti, he insists not only on the condition of invariable concomitance, but also on that of an inner necessity connecting the two terms of the relation. We shall see later that some Indian logicians were content with the first only of these two conditions.
It may be assumed that there is practical agreement in regard to this point among the several Buddhistic schools. but no express statement to that effect can be quoted. That inference is a pramāņa, however, is admitted by all the Buddhists, though, as we shall see, it can have only a provisional value according to them. But they differ sharply from one another in respect of the view they hold of perception. In fact, according to Hindu writers, the division of Buddhistic thought into the four schools which alone they seem to recognize and with which we are concerned here is based chiefly upon the difference in this respect. To explain that difference, we may divide the four schools first into two classes-realistic and idealistic. The former which are Hinayāna believe in the existence of objects outside and independently of knowledge, though the objects according to the general postulate of Buddhism are conceived as momentary. The latter, on the other hand, which are Mahāyāna deny such objects altogether. Of the former, the Vaibhāşikast hold that objects are directly · Vibhāşă is the commentary on the Abhidharma books; and the Vaibhāşikas were so called because they accepted this commentary as finally authoritative. The Sauträntikas on the other hand were of