THE INTERPRETER I5I 



found only " cunning phrases for answers," ' his in- 

 terest in metaphysics had been deep and constant. 

 He had only scorn for the logomachies of the 



"pure metaphysicians," who attempt to base the 

 theory of knowing upon supposed necessary and uni- 

 versal truths, and assert that scientific observation is 

 impossible unless such truths are already known and 

 implied, which to those who are not " pure metaphy- 

 sicians " seems very much as if one should say that 

 the fall of a stone cannot be observed unless the law 

 of gravitation is already in the mind of the observer. 2 

 The roots of every system of philosophy lie deep 

 among the facts of physiology. No one can doubt 

 that the organs and the functions of sensation are as 

 much a part of the province of the physiologist as 

 are the organs and functions of motion or those of 

 digestion ; and yet it is impossible to gain an ac- 

 quaintance with even the rudiments of the physiology 

 of sensation without being led straight to one of the 

 most fundamental of all metaphysical problems. In 

 fact, the sensory operations have been, from time im- 

 memorial, the battle-ground of philosophers. 3 



Wherefore, in the preface to the latest edition of 

 Hume, he caustically advises those "who desire to 

 discourse fluently and learnedly about philosophical 

 questions to begin with the Ionians and to work 

 steadily through to the latest speculative treatise ; ' 

 while for those who " are animated by the much rarer 

 desire for real knowledge," and who want to get a 

 clear conception of the " deepest problems set before 



1 Ante, p. 3. 2 Coll. Essays, vi. p. 62. s Coll. Essays, vi. p. 291. 



