How does Harry win over Dorian? What are his arguments? Which one is most effective?

Lord Henry invites Dorian into Basil's garden as he delivers his lecture on youth, beauty, and the value of immorality. This Eden-like setting emphasizes the fact that Dorian's response to Henry's words represents the boy's fall from grace; it is Dorian's original sin.

Dorian's initial response to the portrait recalls the statement made in the preface that "Those who find ugly meanings in beautiful things are corrupt without being charming." The painting is a masterpiece, certainly a "beautiful thing," but the image sparks jealousy and hatred in Dorian because it reminds him of the fleeting nature of his own youth. He is already "corrupt without being charming," but this marks the starting point of his steady fall from grace.