Finch knows that Violet is made of the exact same stuff as everyone else, but she seems to be made of something more. He makes himself concentrate on Violet instead of his racing thoughts and song ideas. After they have sex, Finch drives Violet home. He takes a detour, though. At the bottom of the Purina Tower, he says he wants to tell Violet a story up there. At the top, wrapped in a blanket, Finch tells her about Sir Patrick Moore, who used to host a nighttime BBC program called Sky. On April 1, 1976, Sir Patrick Moore told viewers that Pluto, Jupiter, and Earth would align—and gravity would temporarily lessen on Earth. He called this phenomenon the Jovian-Plutonian gravitational effect.
The novel implies that, for the most part, Finch is successful in suppressing his thoughts to focus on Violet. This shows how beneficial it can be to connect with another person: Finch now has more impetus and more tools to control his inner monologue. Returning to the Purina Tower afterwards suggests that Finch wants to revisit the idea that the little things matter most (which is what he proposed to her the last time they visited the tower).
Sir Patrick Moore told people they could jump in the air and experience the effect. Sure enough, hundreds of people called into the show. Violet asks if this is real, and Finch reveals that it was just an April Fool’s joke. Violet scolds Finch for telling her something that sounded real, but Finch says he mentions it because he feels like he’s floating now.
The fact that Finch feels like he’s floating now, even though he’s not, recalls his earlier assertion that lies aren’t really lies if they feel true. It doesn’t matter, in other words, what’s actually true. A person’s lived experience is, much of the time, going to be more important to them—even if their perceptions aren’t technically correct.