APPRECIATION OF INTELLIGENCE 23 



on this point can be other than ' relatively as well as abso- 

 lutely valueless', and finally suggests that the memoir will 

 act ' as a warning that in future surveys, intelligence will be 

 a very difficult character to deal with — if indeed it should 

 be included at all '. 



Now Mr. Yule has devoted an immense amount of time 

 and trouble to the analysis of Dr. Warner's data, but 

 nowhere has he a word of criticism for the estimates of 

 intelligence used. Will it be believed that in Dr. Warner's 

 investigation not only was the estimate of intelligence made 

 by the school teachers,^ but also that while in the L.C.C. 

 investigation five categories of intelligence were used : 

 ' brilliant ', ' above the average ', ' average ', ' under the 

 average', 'very dull and backward', in Dr. Warner's in- 

 vestigation the children were divided into two groups only, 

 those ' under the average ', and those not so classed ? ^ 



^ Mr. Yule further assumes throughout his investigation that mental defect is 

 only the extreme grade of poor intelligence, the possibility of its being a patho- 

 logical entity is never even referred to. The world is no doubt a mad world, 

 and it may be impossible in many cases to draw the line between eccentricity and 

 madness ; yet that many cases of insanity are pathological would be accepted 

 by most investigators. Medical opinion at the present time is certainly in 

 favour of some cases of mental defect being also pathological in character. 

 We may be unable to define the limit at which normal stature and ateleiotic 

 dwarfism meet, but few would be found to deny the pathological character of 

 the latter. It is precisely so with mental defect and dullness. One of the 

 points at present of essential importance is the discovery of an adequate 

 definition of mental defect, which will suffice to differentiate two categories, 

 the distinction of which is felt rather than formulated by both medical officer 

 and teacher. The removal of this pathological element from our data should 

 in itself have been sufficient to invalidate any comparison of the correlations 

 founded on the L.C.C. records and Dr. Warner's data. 



2 This type of criticism of Galton Laboratory Memoirs is becoming in- 

 creasingly frequent. All investigations of social problems are declared invalid 

 unless they conform to certain laws laid down by the critics, and it might be 

 supposed that these laws are to be applied to all investigations of the same 

 problem, but that is not so ; these laws are merely formulated for the purpose 

 of ruling out of court any investigation with the results of which the critic does 

 not happen to agree, and are quietly dropped when the results are, from the 

 critic's point of view, satisfactory. 



