If, however, for this paradoxical prude's comfort, an editor attempted to dilute or omit scenes that a certain type of mind might call "aphrodisiac" […], one would have to forego the publication of "Lolita" altogether, since those very scenes that one might ineptly accuse of a sensuous existence of their own, are the most strictly functional ones in the development of a tragic tale tending unswervingly to nothing less than a moral apotheosis. (Fore.4)
The person introducing Lolita to us has certain ideas he wants to express. He wants to prepare the reader for what we would call "adult content." Don't be aroused by the material or assume that it is there for gratuitous reasons: they had to include it for moral reasons.
No doubt ["H.H."] is horrible, he is abject, he is a shining example of moral leprosy, a mixture of ferocity and jocularity that betrays supreme misery perhaps, but is not conducive to attractiveness. (Fore.5)
The author in the introduction is really into the whole moral lesson of the novel. He also misreads Humbert in many ways. Reread this Foreword when you finish the novel.
Book 1, Chapter 4
When I try to analyze my own cravings, motives, actions and so forth, I surrender to a sport of retrospective imagination which feeds the analytic faculty with boundless alternatives and causes each visualized route to fork and re-fork without end in the maddeningly complex project of my past. (1.4.1)
OK, a lot of big words in here. Humbert really wants to turn the novel into an exercise of reflection, but it isn't easy.
Book 1, Chapter 5
One moment I was ashamed and frightened, another recklessly optimistic. Taboos strangled me. (1.5.9)
Even in his early days as a predator, Humbert is torn between desire and law. His emotions are all over the map.
Book 1, Chapter 14
I felt proud of myself. I had stolen the honey of a spasm without impairing the morals of a minor. Absolutely no harm done. (1.14.2)
Humbert comes up with ways to be an undetected pervert. He is not as covert as he thinks.
Book 1, Chapter 20
Simple, was it not? But what d'ye know, folks—I just could not make myself do it! (1.20.32)
Even wicked ol' Humbert couldn't kill Charlotte off to get at Lolita. But we already know he is a murderer…
Book 1, Chapter 25
Instead of basking in the beams of smiling Chance, I was obsessed with all sorts of purely ethical doubts and fears. (1.25.1)
In spite of the impression he makes of a self-indulgent pervert, Humbert does actually have a moral compass, so to speak. He makes it very challenging to establish a complete and clear portrait of his character.
Book 2, Chapter 31
A couple of years before, under the guidance of an intelligent French-speaking confessor, to whom, in a moment of metaphysical curiosity, I had turned over a Protestant's drab atheism for an old-fashioned popish cure, I had hoped to deduce from my sense of sin the existence of a Supreme Being. (2.31.1)
Humbert has considered his place in a world in which God exists. Whether he actually believes in God is not clear.
The moral sense in mortals is the duty / We have to pay on mortal sense of beauty. (2.31.2)
In a typical poetic flourish, Humbert tries to act as though it is his moral obligation to appreciate beauty. What does this little verse suggest about his willingness to be accountable for his behavior?
Book 2, Chapter 35
"We are men of the world, in everything—sex, free verse, marksmanship. If you bear me a grudge, I am ready to make unusual amends […] but really, my dear Mr. Humbert, you were not an ideal stepfather." (2.35.77)
Even though Quilty is a pervert, he does have a good point. Quilty is perhaps more honest about his flaws.