234 ON THOUGHT IN MEDICINE. 



sight into the action of his optical instrument, in like 

 manner every scientific enquirer must study minutely 

 the chief instrument of his research as to its capabili- 

 ties. The groping of the medical schools for the last 

 two thousand years is, among other things, an illus- 

 tration of the harm of erroneous views in this respect. 

 And the physician, the statesman, the jurist, the 

 clergyman, and the teacher, ought to be able to build 

 upon a knowledge of physical processes if they wish 

 to acquire a true scientific basis for their practical ac- 

 tivity. But the true science of philosophy has had, 

 perhaps, to suffer more from the evil mental habits and 

 the false ideals of metaphysics than even medicine 

 itself. 



One word of warning. I should not like you to 

 think that my statements are influenced by personal 

 irritation. I need not explain that one who has such 

 opinions as I have laid before you, who impresses on 

 his pupils, whenever he can, the principle that ' a 

 metaphysical conclusion is either a false conclusion or 

 a concealed experimental conclusion,' that he is not 

 exactly beloved by the votaries of metaphysics or of 

 intuitive conceptions. Metaphysicians, like all those 

 who cannot give any decisive reasons to their oppo- 

 nents, are usually not very polite in their controversy ; 

 one's own success may approximately be estimated 

 from the increasing want of politeness in the replies. 



