12 Animal Intelligence 
servers to be required to identify the fact he is thinking 
of, it is sure that there might be an enormous variability in 
their guesses as to what the fact was and that his testimony 
might be worth far more than that of all the other nineteen 
without his testimony. His observation is influenced by 
the action of the neurones in his central nervous system as 
theirs is not, and, in the case of the thought ‘g x 7 equals. 
63,’ the action of these neurones is of special importance. | 
Our examination of the way science treats these six facts | 
shows no impassable cleft between knowledge of a man’s. 
body and knowledge of his mind. _| Scientific statements 
about the toothache, anxiety and numerical judgment are 
in general more variable than statements about length, 
hair-color and _ body-tem| erature, but there is here no 
difference save of degree! Some physical facts, such as 
hair-color, eye-color or health, are, in fact, judged more 
variably than some mental facts, such as rate of adding, 
accuracy of perception of a certain sort and the like. So: 
far as the lack of agreement amongst impartial observers 
goes,’ there is continuity from the identification of a length: 
to that of an ideal. 
“ Scientific judgments about the facts of John’s mind 
‘also depend, in general, more upon his verbal reports than 
do judgments about his body. But here also the difference 
is only of degree. The physician studying wounds, ulcers, 
tumors, infections and other facts of a man’s body may 
depend more upon his verbal reports than does the moral- 
ist who is studying. the man’s character. Verbal reports 
too are themselves a gradual and continuous extension of 
coarser forms of behavior. They signify consciousness. 
no more truly than do signs, gestures, facial expressiot 
and the general bodily motions of pursuit, retreat, avrid- 
ance or seizure. sl 
