232 Induction. [CHAP. IX. 



for the most part of the empirical kind, than to meet with 

 suggestions which point more or less directly in contrary 

 directions. Whenever some new substance is discovered or 

 brought into more general use, those who have to deal with 

 it must be familiar with such a state of things. The medical 

 man who has to employ a new drug may often find him 

 self confronted by the two distinct recommendations, that on 

 the one hand it should be employed for certain diseases, and 

 that on the other hand it should not be tried on certain con 

 stitutions. A man with such a constitution, but suffering 

 from such a disease, presents himself; which recommenda 

 tion is the doctor to follow ? He feels at once obliged to 

 set to work to collect narrower and more special statistics, 

 in order to escape from such an ambiguity. 



31. In this and a multitude of analogous cases 

 afforded by the more practical arts it is not of course neces 

 sary that numerical data should be quoted and appealed 

 to ; it is sufficient that the judgment is more or less con 

 sciously determined by them. All that is necessary to make 

 the examples appropriate is that we should admit that in 

 their case statistical data are our ultimate appeal in the 

 present state of knowledge. Of course if the empirical 

 laws can be resolved into their component causes we may 

 appeal to direct deduction, and in this case the employ 

 ment of statistics, and consequently the use of the theory of 

 Probability, may be superseded. 



In this direction therefore, as time proceeds, the advance 

 of statistical refinement by the incessant subdivision of classes 

 to meet the developing wants of man is plain enough. But 

 if we glance backwards to a more primitive stage, we shall 

 soon see in what a very imperfect state the operation com 

 mences. At this early stage, however, Probability and In 

 duction are so closely connected together as to be very apt to 



