He refuses to accept that mountains on the Moon cause shadows, or that reflected light from the Earth is responsible for the faint outline in a crescent moon.

Sagredo holds that he considers the Earth noble because of the changes in it whereas Simplicio says that change in the Moon or stars would be useless because they do not benefit man. Salviati points out that days on the Moon are a month long and despite the varied terrain that the telescope has disclosed, it would not sustain life. Humans acquire mathematical truths slowly and hesitantly,