The whole world of manners and morals is in a state of perpetual ferment and consequent change,—­equally restless and mutable is the world of Nature, for at any moment mountains may become plains, and plains mountains,—­the dry land may be converted into oceans, and oceans into dry land, and so on forever.  In this incessant shifting of the various particles that make up the Universe, how can you expect a man to hold fast to so unstable a thing as an idea!  And, respecting the testimony offered by sight and sense, can you rely upon such slippery evidence?”

Theos moved uneasily,—­a slight shiver ran through his veins, and a momentary dizziness seized him, as of one who gazing down from some lofty mountain-peak sees naught below but the white, deceptive blankness of a mist that veils the deeper deathful chasms from his eyes.  Could he rely on sight and sense...Dared he take oath that these frail guides of his intelligence could never be deceived? ...  Doubtfully he mused on this, while his companion continued: 

“For example, I look an arm’s length into space, . . my eyes assure me that I behold nothing save empty air,—­my touch corroborates the assertion of my eyes,—­and yet, . .  Science proves to me that every inch of that arm’s length of supposed blank space is filled with thousands of minute living organisms that no human vision shall ever be able to note or examine!  Wonder not, therefore, that I decline to express absolute confidence in any fact, however seemingly obvious, such as that two and two are four, and that I prefer to say the blood-red color of this river may be caused by an earth-tremor or a land-slip, rather than positively assert that it must be so; though I confess that, as far as my knowledge guides me, I incline to the belief that ‘must be’ is in this instance the correct term.”

He sighed again, and rubbed his nose perplexedly.  Theos glanced at him curiously, uncertain whether to laugh at or pity him.

“Then the upshot of all your learning, sir, . .” he said, . . “is that one can never be quite certain of anything?”

“Exactly so!”—­replied the pensive sage with a grave shake of his head,—­“Judged by the very finest lines of metaphysical argument, you cannot really be sure whether you behold in me a Person or a Phantasm!  You think you see me,—­I think I see you,—­but after all it is only an impression mutually shared,—­an impression which like many another, less distinct, may be entirely erroneous!  Ah, my dear young sir!—­education is advancing at a very rapid rate, and the art of close analysis is reaching such a pitch of perfection that I believe we shall soon be able logically to prove, not only that we do not actually exist, but moreover that we never have existed! ...  And herein, as I consider, will be the final triumph of philosophy!”

“A poor triumph!”—­murmured Theos wearily.  “What, in such a case, would become of all the nobler sentiments and passions of man,—­ love, hope, gratitude, duty, ambition?”