Role Of Drstanta Indignagas Logic

Author(s): Shoryu Katsura
Publisher: Shoryu Katsura

Page 12

quantifier'. Generally speaking, Dignaga admits the following two ways in order to express a logical relation or vyapti in Sanskrit:
(1) yad P tad Q/
(2) Q eva P/
&
&
yad -Q tad -P/
-P eva -Q/
Dignaga is very much concerned with the problem of how to formulate a logical proof in a proper way. We can now present his formulation in a formal manner. 'a' stands for a topic of a proposition (pakṣa) or an object of inference (anumeya); P stands for a proving property (sadhana-dharma), a reason (hetu), or an inferential mark (linga); Q stands for a property to be proved (sādhya-dharma); s stands for a similar example (sädharmya-dṛṣṭānta) or a member of a set of similar examples (sapakṣa); and v stands for a dissimiar example (vaidharmyadrştänta) or a member of a set of dissimilar examples (vipakṣa). It is to be noted that in Dignaga's system of logic a, being a topic under examination, is not a part of our Induction Domain which consists of sapakṣa and vipakṣa. Furthermore, the underlying structure of an Indian proof statement is: "A property-possessor (dharmin) a possesses a property (dharma) P"; the notion of 'possession' is expressed by the Genitive or the Locative case ending or by the suffixes of possession, i.e., -mat and -vat, or even by the convention of elision of those suffixes (matup-lopa).
[proposition] "a possesses Q."
[reason] "Because a possesses P."
[similar ex.] "It is observed that whatever possesses P possesses Q as e.g.
S."
[dissimilar ex.] "It is observed that whatever does not possess Q does not possess P as e.g. v."
We can somehow translate the above formulae into the following standard symbolism but it is impossible to convey the sense of 'it is observed that ...' without introducing some device of Modal Logic:
Dignaga on Example - 12