While investigating the nature of inference, Buddhist logicians hit upon the problem of analytic-synthetic judgements. That inferential judgements, grounded in experience or on the law of causation, are synthetic, has never been doubted. Neither has it been disputed that there are other judgements in which the predicate is a part of the subject, wherein the mere existence of the subject is sufficient to deduce the predicate.
A synthetic judgement is always experimental; an analytic judgement is always ratiocinative.
The use of the understanding is double; it either is purely logical and consists in bringing order and system into our concepts, or it is experimental and consists in establishing causal relations by observation and experiment.
Dharmottara says causality is a conception familiar in common life. It is known to be derived from experience of the cause wherever the effect is present, and from the negative experience of the absence of the effect when its cause is absent. The identity upon which the analytic judgement is based is not a familiar concept. Its definition is therefore given by Dharmakirti.
"Identity is a reason for deducing a predicate when the subject alone is by itself sufficient for that deduction" i.e., when the predicate is part of the subject. It is therefore not absolute Identity. It is a partial identity.
Dharmottara explains, "what kind of logical reason consists in its merely being contained in its own predicate ? This predicate possesses the characteristic of existing wherever the mere existence of the reason/hetu is ascertained. (A predicate whose presence is dependent on the mere existence of the reason, and is dependent on no other condition beside the mere
existence of the fact constituting the reason, such is the predicate which is inseparable from the reason and can be analytically deduced from it.)
Table of Categories : according to the Indian method of counting the ultimate items in a classification, there are only 3 categories of Relation between two concepts , viz., Negation, Identity and Causality. Subordinate and derivative kinds are not counted. Identity and Causality are affirmations of necessary dependence.
Dharmottara asks with respect to the three ultimate items of this classification : ' There are different varieties of those relations upon which inference is founded. Why do we reckon only 3 items ? The varieties may be innumerable. '
Dharmakirti answers : Inferential cognition is either Affirmation or Negation, and
Affirmation is double; it is either founded on Identity or on Causality. This means that since the division is made according to the principle of dichotomy , the parts are exclusive of each other ; there can be nothing between them. The Law of Excluded Middle precludes any such thing.
The affirmative judgement can either be analytic or synthetic, i.e. either based on Identity or non-identity/ causality : the interdependence or synthesis of non- identical facts. The division of all judgements into analytic-synthetic, into Identity and Causality must be deemed
logically correct in accordance with the law of excluded middle.
What is here called identity is an identity or union of two different concepts which may be identical in extension but both refer to the same objective reality, e.g., the concepts of 'tree'
and 'simsapa' are different yet the particular thing to which they refer is identical; it is just the same.
On the other hand, a concept may be the same or the difference between them undiscernable yet the real thing to which they refer will be different ,e.g., this same simsapa at two different moments of its existence. Two moments of the simsapa are two different things, causally related.
Thus the term 'synthetic' refers to a synthesis of two different things, the term analytic to a synthesis of two different concepts. The fact that all judgements are divided into affirmation and negation is firmly established in logic since the time of Aristotle who even introduced this division into his definition of inferential judgement.
It is therefore wrong to coordinate the parts of this division with other items belonging to other divisions because the parts will then necessarily be overlapping. Is the Buddhist table of relations exhaustive ? Are there no other relations representing valid reasons ? Why should only these three relations viz., Negation of an assumed presence ( anupalabdhi ), Identity ( tadatmya = non-causality) and Causality ( tadutpatti = non-identity of the underlying reality ), represent valid reasons ? Dharmakirti says that 'relations' here means 'dependence'.
A thing can convey the existence of another thing only when it is essentially dependent on it.
Such relations which are reasons/ hetu are relations of necessary dependence.
When the cause of something is to be synthetically deduced, or an essential quality is to be deduced analytically, the effect is essentially dependent on its cause, and the analytically deduced quality is by its essence dependent upon the conception from which it is deduced.
Both these connections are essential dependence. Identity is the logical interdependence of two conceptions having one and the same objective reference. And causality is an
interdependence of two real facts , of which one is the effect of the other..
The Nyaya school refutes both these Buddhist contentions, i.e, they reject the view that there are analytical judgements which are founded on Identity and that all synthetic judgements are founded on causality. An analytic judgement based on Identity does not exist at all. When two conceptions are identical, one of them cannot be the reason for deducing the other, the deduction will be meaningless. If it be objected that reality is the same but superimposed conceptions alone are different, the Realist answers that if the conceptions are different, the corresponding realities also are different.
If concepts were not real, they would not be concepts. The terms 'taru' and 'vrksa' mean a tree.
The judgement 'taru is vrksa' would be founded on Identity but not the judgement 'simsapa'is a tree', because for the realists, simsapa and tree are two different realities; we experience their invariable concomitance ; they are two entities.
Nor are all real relations traceable to causality. There are a great number of invariable concomitances, known by uncontradicted experience, which are not reducible to Identity or Causality ,e.g., the rising of the sun is invariably connected with its rising the day before; the rising of the moon is concomitant with high tide in the sea. When we taste the flavor of some food stuff, we can infer the presence of colour because we know from experience that this kind of flavor is invariably connected with a definite color. This invariable connection cannot
be treated as a case of causality because both phenomena are simultaneous whereas causality is a relation of necessary sequence.
To this the Buddhist replies that all these relations are traceable to causality. The color which exists simultaneously with flavor is related to it only through the medium of the preceding moment in which visual, tactile and the other sense-data represent that complex of causes,in functional dependence on which the next moment of color can arise. What the Nyaya realist calls a stuff is for the Buddhist a complex of momentary sense data. Thus the Inference of color through flavor is founded on simultaneous production by a common cause. Every succeeding instant arises in necessary dependence upon a complex of preceding moments.
