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TESTIMONY AND AUTHOEITY. 65 testimony as sufficiently dealt with in the discussion of Observation. In Venn's Empirical Logic, 1 for example, & passing allusion is made to testimony under the head of Observation. This is to look upon the acceptance of testi- mony as observation or experiment by deputy ; but it clearly results in an incomplete treatment, in so far as it supposes us already furnished with some means of distinguishing the deputies that are trustworthy from those that are not. Still, since the acceptance or rejection of testimony is a process of selection of the material of knowledge, it would seem that even though credence in testimony does not fall wholly under Observation, yet it ranges alongside it. But while Observation and Experiment are directed towards phenomena, the selection now in question is from among statements or assertions. There is no ground for denying ' credence ' if we may use this term to denote critical acceptance of testimony or authority a position co-ordinate with Observation in the supposition that it must necessarily be less certain than first-hand observation, or as it might be put less ' logical'. That testimony may, in certain cases, give even greater certainty than personal observation must be familiar to every one who recognises the great inequalities existing between different individuals in their respective powers. A person may well derive, perhaps in some unfamiliar de- partment of knowledge, a degree of certainty from the affirmation of the qualified expert far surpassing anything he could reasonably derive from his own imperfect or un- trained observation. But Testimony is involved in Inductive Logic in a far more intimate manner than this. It might almost be said that Testimony is necessary not only to the establishment of the universality of the principle of the Uniformity of Nature, but even to the perception of any uniformity in the bulk of Nature's activities. Along with clearly exhibited uniformity in cer- tain respects, Nature presents infinite variety. Some uni- formities only are patent, most are disguised. We see that heavy bodies fall when free, but a balloon rises. The same piece of wood, however often we try it, will always float ; but that a friend on one occasion, say, took wine is no guarantee that he will accept the same thing on another occasion. In such instances it is easy to specify the uni- formities underlying the apparent irregularities ; and in doing so we clearly see that in these as in other cases the 1 Empirical Logic, p. 111. 5