Page:A History of Indian Philosophy Vol 1.djvu/364

 34 8 The Nyiiya- Vaifeika Philosuphy [CH. infer the particular cause from the effect. N yaya holds how- ever that though different causes are often found to produce the same effect, yet there must be some difference between one effect and another. I f each effect is taken by itself with its other attendant circumstances and peculiarities, it will be found that it may then be possible to distinguish it from similar other effects. Thus a flood in the street may be due either to a heavy downpour of rain immediately before, or to the rise in the water of the river close by, but if observed carefully the flooding of the street due to rain will be found to have such special traits that it could be distinguished from a similar flooding due to the rise of water in the river. Thus from the flooding of the street of a special type, as demonstrated by its other attendant circum- stances, the special manner in which the water flows by small rivulets or in sheets, will enable us to infer that the flood was due to rains and not to the rise of water in the river. Thus we see that N yay a relied on empirical induction based on uniform and uninterrupted agreement in nature, whereas the Buddhists assumed a pri01'i principles of causality or identity of essence. It may not be out of place here to mention that in later Nyaya works great emphasis is laid on the necessity of getting ourselves assured that there was no such upadhi (condition) associated with the hetu on account of which the concomitance happened, but that the hetu was unconditionally associated with the sadhya in a relation of inseparable concomitance. Thus all fire does not pro- duce smoke; fire must be associated with green wood in order to produce smoke. Green wood is thus the necessary condition (uPddhi)" without which no smoke could be produced. It is on account of this condition that fire is associated with smoke; and so we cannot say that there is smoke because there is fire. But in the concomitance of smoke with fire there is no condition, and so in every case of smoke there is fire. In order to be assured of the validity of vyapti, it is necessary that we must be assured that there should be nothing associated with the hetu which con- ditioned the concomitance, and this must be settled by wide experience (bhltyodarlana). Prasastapada in defining inference as the" knowledge of that (e.g. fire) associated with the reason (e.g. smoke) by the sight of the reason" described a valid reason (liilga) as that which is con- nected with the object of inference (allu1llcya) and which exists wherever the object of inference exists and is absent in all cases