Pasteboard Masks

Here's the passage from Moby Dick I'm reading in the video if you need it:

Hark ye yet again--the little lower layer.  All visible objects, man, are but as pasteboard masks.  But in each event--in the living act, the undoubted deed--there, some unknown but still reasoning thing puts for the mouldings of its features from behind the unreasoning mask.  If man will strike, strike through the mask!  How can the prisoner reach outside except by thrusting through the wall?  To me, the white whale is that wall, shoved near to me.  Sometimes I think there's naught beyond.  But tis enough.  He tasks me;  He heaps me; I see in him outrageous strength, with an inscrutable malice sinewing it.  That inscrutable thing is chiefly what I hate; and be the white whale agent, or be the white whale principal, I will wreak that hate upon him.  Talk not to me of blasphemy, man; I'd strike the sun if it insulted me.  For if the sun could do that, then I could do the other; since there is ever a sort of fair play herein, jealousy presiding over all creations.  But not my master, man, is even that fair play.  Who's over me?  Truth hath no confines.