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NYAYA THEORY OF KNOWLEDGE
from the abstract principles of logic and mathematics. While the latter are truths about certain universal concepts, the former are truths about classes of things. When we lay down the proposition' all men are mortal,' or 'all smoky objects are fiery,' what we really want to convey is, not that there is a necessary relation between manhood and mortality, or between smokeness and fireness, but that mortality is true of the class of men, or that all smokes are connected with fire. Such propositions are empirical generalisations in the sense that these are assertions about whole classes of things, which are true, and that these are arrived at from observation of particular instances. But what is the nature of the process of knowledge that is involved when we generalıse from some 'to all'in a logically valid way ? Is it any kind of induction ? If so, it must be either perfect induction or “ Induction by Simple Enumeration." A perfect induction is one in which 'from the consideration of each of the members of a limited class we pass to a generalisation concerning all the members of that class. This is exemplified when on examining every boy of a class one says" all the boys of this class are intelligent." With regard to this Stebbing says: 'Mr. Jobnson has suggested the convenient name summary induction for this mode of inference, and that it is certainly a more appropriate name than “ perfect induction.". It seems to me that both names are equally inappropriate, and that for the same reason. A summary of a number of observed facts is not an induction at all. To call it an induction, be it perfect or summary, is to misjudge its epistemic character as inferential If on examining every patient in a sick-room a physician says “ all the patients in this room have got fever,'' then his judgment is not to be described as an induction or inference in any sense. It
1 Modern Introduction to Logic, p. 244.
