Darkness and death
Villanelle describes the unusual Venetian life, the "city of uncertainty". She talks about how she thought that darkness and death were the same thing. That death was nothing more than a shadow of the world where people went on as usual. But, darkness or night is uncertain and temporary while death isn't.
Love/passion is a demon
In one out of, not so rare, contemplations by the character of Villanelle, through which we get to hear the author's tone, she describes the meaning of love-they say that love enslaves and passion is a demon, that love destroyed many. But love is paradoxical, as it allows a person to see the sun and themselves truthfully.
Like God, she was neglected
Henri recalls a man from his home village, a cheery man whom they called an inventor. He had a wife who took care of their land and their children. When she suddenly died, he changed, he was no longer the man they used to know and the land and the children became neglected. The wife made him possible, in that sense she is compared to a god, and just like god she was neglected. The author quite often raises a subject of religion in the novel, more in the negative sense than a positive one.
Freedom like Holy Grail
Towards the end Henri talks about the meaning of freedom and compares it to the Holy Grail-everyone knows it exists and everyone has their own idea of where to find it. He talks about what freedom meant to his friends, his friend priest found it in God, Patrick found it thinking about home, Bonaparte thought freedom lies in fighting, but no one won the Holy Grail by force. Henri sees freedom in love, love that makes a person forget about themselves.