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Speculations in the Medical Schools
[CH.
siderations detailed in the preceding footnote it may well be assumed that Akṣapada's contribution to the definition of inference consists in his giving names to the types of floating inference described in Caraka-samhita. It is not improbable that the Nyaya-sūtra derived its theory of five propositions, and in fact most of the other logical doctrines, from Caraka, as there are no earlier works to which these can be traced1. Caraka's definition of perception as the knowledge
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different times. But he also gives another meaning of these three terms purvavat, seṣavat and sāmānyato-dṛṣṭa. He interprets purvavat here as the inference of fire from smoke "on the analogy of past behaviour of co-presence," seṣavat as the inference of the fact that sound is quality because it is neither substance nor action, by the method of residues (sesa), and samanyato-drsta as the inference of the existence of soul from the existence of desire, which is a quality and as such requires a substance in which it would inhere. This is not an inference from similarity of behaviour, but from the similarity of one thing to another (e.g. that of desire to other qualities), to extend the associations of the latter (inherence in a substance) to the former (desire), i.e. the inference that desire must also inhere in a substance.
In the case of the terms purvavat and seṣavat, as these two terms could be grammatically interpreted in two different ways (with matup suffix in the sense of possession and vati suffix in the sense of sirnilarity of behaviour), and as the words pūrva and seșa may also be used in two different ways, Vātsyāyana interprets them in two different ways and tries to show that in both these senses they can be justified as modes of inference. It seems obvious that the names purvavat, seṣavat and sāmānyato-drsta were given for the first time to the threefold inference described by Caraka, as this explains the difficulty felt by Vatsyāyana in giving a definite meaning to these terms, as they had no currency either in traditional or in the contemporaneous literature of Vatsyayana. Uddyotakara, in his commentary on Vätsyāyana, contributes entirely original views on the subject. He takes Akṣapada's sūtra, atha tat-pūrvakam tri-vidham anumānam pūrvavac cheṣavat samanyato-dṛṣṭam ca, and splits it up into atha tat-pūrvakam tri-vidham anumanam and purvavac cheṣavat samanyato-dṛṣṭam ca; by the first tri-vidha he means inference from positive instances (anvayi), from negative instances (vyatireki) and from both together (anvaya-vyatireki). He gives two possible interpretations of the terms pūrvavat, seṣavat and sāmānyato-dṛṣṭa, one of which is that purvavat means argument from cause to effect, sesavat that from effect to cause and sāmānyato-dṛṣṭa is the inference on the basis of relations other than causal. The Samkhya-karikā also mentions these kinds of inference. The Mathara-vṛtti again interprets the threefold character of inferences (tri-vidha anumāna) in two ways; it says, firstly, that tri-vidha means that an inference has three propositions, and, secondly, that it is of three kinds, viz. pūrvavat (from the effect, e.g. flooding of the river, to the inference of the cause, e.g. showers in the upper region), śeşavat (from part to whole, e.g. tasting a drop of sea-water to be saline, one infers that the whole sea is saline), and sāmānyato-drşta (inference from general association, e.g. by seeing flowering mangoes in one place one infers that mangoes may have flourished in other places as well). Curiously enough, the Mathara-vṛtti gives another example of samanyato-dṛṣṭa which is very different from the examples of samanyato-dṛṣṭa hitherto considered. Thus it says that, when one says, "It is illuminated outside," another replies, "The moon must have risen."
1 For more or less fanciful reasons Mr Dhruva suggests that the terms purvavat and seṣavat were borrowed in the Nyaya-sutra from the Mimämsä-sutra and that this sūtra must therefore be very old (Proceedings and Transactions of the First Oriental Conference, Poona, 1922). This argument is invalid for more
