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Jaina seven-valued logic is a system ofargumentation developed byJainaphilosophers and thinkers in ancient India to support and substantiate their theory ofpluralism. This argumentation system has seven distinct semanticpredicates which may be thought of as seven differenttruth values. Traditionally, in the Jaina and other Indian literature dealing with topics inJain philosophy, this system of argumentation is referred to asSaptabhangivada orSyadvada. The earliest reference toSyadvada occurs is the writings ofBhadrabahu (c. 433–357 BCE). There is mention ofSyadvada in theNyayavatara of Siddhasena Divakara (about 480–550 CE). Samantabhadra (about 600 CE) gave a full exposition of the seven parts ofSyadvada orSaptabhanginyaya in hisAptamimamsa. TheSyadvadamanjari of Mallisena (1292 CE) is a separate treatise on the same theory. There are, of course, still later works and a large number of modern commentaries.[1] The interpretation of Saptabhangivada as aseven-valued logic was attempted byHarvard University philosophy professor George Bosworth Burch (1902–1973) in a paper published in International Philosophical Quarterly in the year 1964.[2]P. C. Mahalanobis, an Indian applied statistician, has given aprobabilistic interpretation of theSaptabhangivada.[1][3]
TheSaptabhangivada, the seven predicate theory may be summarized as follows:[4]
The seven predicate theory consists in the use of seven claims about sentences, each preceded by "arguably" or "conditionally" (syat), concerning a single object and its particular properties, composed of assertions and denials, either simultaneously or successively, and without contradiction. These seven claims are the following.
There are three basic truth values, namely, true (t), false (f) and unassertible (u). These are combined to produce four more truth values, namely, tf, tu, fu, and tfu (Three-valued logic). Though, superficially, it appears that there are only three distinct truth values a deeper analysis of the Jaina system reveals that the seven truth values are indeed distinct. This is a consequence of the conditionalising operator "arguably" denoted in Sanskrit by the wordsyat. This Sanskrit word has the literal meaning of "perhaps it is", and it is used to mean "from a certain standpoint" or "within a particular philosophical perspective".
In this discussion the term "standpoint" has been used in a technical sense. Consider a situation in which a globally inconsistent set of propositions, the totality of philosophical discourse, is divided into sub-sets, each of which is internally consistent. Any proposition might be supported by others from within the same sub-set. At the same time, the negation of that proposition might occur in a distinct, though possibly overlapping subset, and be supported by other propositions within it. Each such consistent sub-set of a globally inconsistent discourse, is what the Jainas call a "standpoint" (naya). A standpoint corresponds to a particular philosophical perspective.[4]
In this terminology, it can be seen that the seven predicates get translated to the following seven possibilities. Each propositionp has the following seven states:[4]
In common propositional logic, a contradiction and the rejection of the Excluded Middle statement can both be rejected, i.e. provenFalse, and they are there thus formally equivalent. Indeed, this already holds inminimal logic, for example.The situation is more refined in the other logics discussed:
| Saptabhangi Logic | Catuṣkoṭi Logic | Aristotelian logic |
|---|---|---|
| It is | It is | It is |
| It is not | It is not | It is not |
| It is and it is not | It is and it is not | |
| It is unassertible | It is neither | |
| It is and it is unassertible | ||
| It is not and it is unassertible | ||
| It is and it is not and it is unassertible |
| True | False |
| Unassertible | Unassertible |
| False | True |