________________
GROUNDS OF INFERENCE
271 vyâpti or unconditional concomitance. If even after repeated observation we have any doubt as to there being vyāpti or a universal relation between the middle and major terms, we are to have recourse to tarka or indirect proof to end such doubt. Thus the universal proposition, all cases of smoke are cases of fire,' may be proved indirectly by disproving its contradictory If this universal proposition be false, then its contradictory, 'some cases of smoke are not cases of fire,' must be true. This means that there may be smoke without fire. But the supposition of smoke without fire is contradicted by the known relation of causality between fire and smoke. To say that there may be smoke without fire is to say that there may be an effect without its cause, which is absurd. If any one has the cbstinacy to say that sometimes there may be effects without causes, he must be silenced by the practical contradictions (vyághāta) involved in the supposition If there can be an effect without a cause, why should be constantly seek for fire to produce smoke or for food to alleviate his hunger ? Thus its contradictory being proved to be false, the universal proposition all cases of smoke are cases of fire' comes out as true, 1.e. there is vyāptı or a universal relation between smoke and fire. 2
So far the Naiyāyikas try to establish vyāpti or a universal proposition by the method of simple enumeration supported by tarka or a hypothetical reasoning wbich indirectly proves its validity By examining a number of positive and negative instances of agreement in presence and absence between two things, they conclude that there is a universal relation between them. This conclusion is then indirectly confirmed by showing that a denial of the universal relation between these two things leads to contradictions. But as we have already seen in connection
1 3
Vide, TB, pp. 7-8 Vide SM., 187 : TC, II, pp 210-12,
