SENSATION AND THE SENSIFEROUS ORGANS. 271 



solid information about sensation, giving way to not un- 

 natural 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 properties 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 ex- 

 cursion 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 dis- 

 cipline 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 existence 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 which renders its possessor proof 



