Quote 1
"Vengeance on a dumb brute!" cried Starbuck, "that simply smote thee from blindest instinct! Madness! To be enraged with a dumb thing, Captain Ahab, seems blasphemous."
"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 forth 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." (36.38-39)
Both parts of this dialogue contain some of the most important keys to unlocking the theme of revenge in Moby-Dick. Starbuck claim that trying to take revenge on a simple animal, which isn’t capable of hatred or cruelty, is not just stupid—it’s sinful.
In response, Ahab claims that the entire world has an allegorical or neo-Platonic aspect: all things represent other things and everything happens for a purpose. Much of the tension in the novel relates to this fundamental difference in interpretation: Starbuck sees the natural world as simply there, doing its thing, and Ahab sees it as the tangible representation of "some unknown but still reasoning thing." At bottom, the issue is whether or not Moby Dick attacked Ahab with "malice aforethought," as those legal types say.
Quote 2
My soul is more than matched; she’s overmanned; and by a madman! Insufferable sting, that sanity should ground arms on such a field! But he drilled deep down, and blasted all my reason out of me! I think I see his impious end; but feel that I must help him to it. Will I, nill I, the ineffable thing has tied me to him; tows me with a cable I have no knife to cut. Horrible old man! Who’s over him, he cries; – aye, he would be a democrat to all above; look, how he lords it over all below! Oh! I plainly see my miserable office, – to obey, rebelling; and worse yet, to hate with touch of pity! For in his eyes I read some lurid woe would shrivel me up, had I it. Yet is there hope. Time and tide flow wide. The hated whale has the round watery world to swim in, as the small gold-fish has its glassy globe. His heaven-insulting purpose, God may wedge aside. (38.1)
Very early in the novel, Starbuck realizes—or decides—that it will be his fate to help Ahab with his sacrilegious revenge quest, even though he knows it’s wrong. It’s possible that he has a flash vision of his future, in which he discovers what his role in this story is going to be. But it’s also possible that, at this moment, he abdicates all responsibility for his actions and hides behind "Destiny."