264 SENSATION AND THE SENSIFEROUS ORGANS. [LECT. 



into reading thus far by the hope of getting positive 

 solid information about sensation, giving way to not 

 unnatural irritation, may here interpellate : " The 

 upshot of all this long disquisition is that we are 

 profoundly ignorant. We knew that to begin with, 

 and you have merely furnished another example of 

 the emptiness and uselessness of metaphysics." But 

 I venture to reply, Pardon me, you were ignorant, but 

 you did not know it. On the contrary, you thought 

 you knew a great deal, and were quite satisfied with 

 the particularly absurd metaphysical notions which 

 you were pleased to call the teachings of common 

 sense. You thought that your sensations were pro- 

 perties of external things, and had an existence 

 outside of yourself. You thought that you knew 

 more about material than you do about immaterial 

 existences. And if, as a wise man has assured us, 

 the knowledge of what we don't know is the next 

 best thing to the knowledge of what we do know, 

 this brief excursion into the province of philosophy 

 has been highly profitable. 



Of all the dangerous mental habits, that which 

 schoolboys call " cocksureness " is probably the most 

 perilous ; and the inestimable value of metaphysical 

 discipline is that it furnishes an effectual counterpoise 

 to this evil proclivity. Whoso has mastered the 

 elements of philosophy knows that the attribute of 

 unquestionable certainty appertains only to the ex- 

 istence of a state of consciousness so long as it exists ; 

 all other beliefs are mere probabilities of a higher 

 or lower order. Sound metaphysic is an amulet 



